Photos by Wayside Gardens / www.waysidegardens.com
Amsonia hubrechtiiAmsonia hubrechtiiby George Papadelis

September is too often considered a challenging month for perennial gardeners. Many of us believe mums are the only annual or perennial that provides interest in the fall. Nothing could be further from the truth. In sunny areas, try perennials like Sedum ‘Autumn Joy,’ hardy plumbago (Ceratostigma), boltonia, asters, blue mist spirea (Caryopteris), and ornamental grasses, just to name a few. In shady spots, try anemones, toad lilies (Tricyrtis), yellow wax bells (Kirengeshoma), hosta plantaginea, and fall-blooming crocus. And don’t forget about pansies. They are getting easier to find in the fall, and if planted then, they can bloom until Christmas or longer. Amsonia is yet another one of these late season performers whose color and durability make it a must for the fall garden.

Amsonia is rarely referred to by its common name “blue star.” Unlike most perennials, this one exhibits striking fall color that is more typical of many trees and shrubs. By late September, amsonia’s tight mound of olive-green, willow-like foliage takes on a brilliant yellow-gold color. This blends beautifully with other fall color, whether from mums or shrubs. Even before the fall show develops, these rounded mounds of fine foliage provide handsome forms and textures in the summer garden. Flowers too? Yes! In the spring, amsonia is covered with small, pale blue, star-shaped flowers, from which the common name is derived. Like many perennials, these only last a few weeks. It is the foliage of this plant which deserves recognition and more frequent use in the garden.

Amsonia tabernaemontanaAmsonia has one other rare quality. This eastern U.S. native thrives in heavy, moist soil. “Heavy, moist” means clay and many of us have plenty of it. Use organic soil amendments like compost and peat moss when planting, but some clay will make amsonia feel right at home. Blue star is also long-lived, so dividing or replacing it will rarely be necessary. Position the plant in sun or partial sun and let time do the rest. After one year in the garden, you have plants large enough to draw attention. Keep in mind amsonia’s broken stems release a milky sap that may cause skin irritation.

Two types of amsonia are readily available and vary only in leaf form. Willow leaf amsonia or blue star (Amsonia tabernaemontana) has wider leaves resembling those of a willow tree, while Arkansas blue star (Amsonia hubrichtii) has very narrow leaves. Naturally, the latter species produces foliage effects that are finer and lighter in texture. Both types grow 2 to 3 feet tall and have great fall color.

If big, bright flowers are all you need in your fall garden, mums are probably your best bet. On the other hand, amsonia provides tidy mounds of beautifully textured foliage followed by outstanding fall color for years and years. Try it with some of the previously mentioned fall performers for a late season show you’re sure to enjoy.

George Papadelis is the owner of Telly’s Greenhouse in Troy.

At a glance: Amsonia

Pronunciation: am-SO-nee-ah

Common name: Blue star

Plant type: Perennial

Plant size: 24-36” tall, 36” wide

Flower color: Pale blue, star-shaped

Flower size: 1” across

Bloom period: Late spring to early summer

Leaves: Green; 2-6” long; 1/2-1” wide or very fine, depending on variety

Light: Full to part sun

Soil: Only moderately fertile, moist soil; prefers some clay content; if soil is too fertile, plant may tend to flop 

Uses: Perennial border; use for its foliage texture, especially in the fall.

Companion plants: Sedum ‘Autumn Joy,’ ornamental grasses, boltonia, Russian sage, asters, blue mist spirea

Remarks: Fantastic golden yellow fall color. Long-lived perennial; frequent division is not necessary.

W. Atlee Burpee & Co. / 800-888-1447
Chelone lyonii ‘Hot Lips’by George Papadelis

Garden centers fill their benches in the fall with thousands of mums. But what else is blooming? With a little effort, dozens of great perennials that bloom during early fall can be found. Chelone, or turtlehead, is a North American native perennial whose peak flowering period lasts about four weeks from August to September.

Chelone has the common name turtlehead because its individual florets resemble the head of a turtle. The individual flowers are about 1 inch long and are borne on short, pointed spikes that rest above glossy green foliage. Plants grow 2 to 3 feet tall and about 1-1/2 to 2 feet wide. Turtlehead prefers moist, rich soil and partial sun but can tolerate full sun if provided adequate moisture. It grows in and close to woodlands all over the eastern half of the U.S. and Canada. Like many native plants, it is well adapted to our climate and soils and is also more insect- and disease-resistant. Turtlehead will last for many years with little or no care at all. When plants grow beyond their allocated space, they can be easily divided in spring.

K. Van Bourgondien & Sons / 800-622-9997
Chelone obliquaThree species of Chelone are readily available and each offers some traits that may be beneficial in your garden. Chelone glabra is often called white turtlehead (or swamp turtlehead) because its flowers are usually white tinged with a hint of pink. It blooms a bit earlier than the other two species, starting in late July and continuing through August. Of the three species, this one is the most sun-tolerant.

Chelone lyonii is the most popular turtlehead. It is usually pink, prefers partial sun and blooms about the same time as Chelone glabra. The variety ‘Hot Lips’ has rich pink flowers and reddish stems.

Chelone obliqua has flowers of the deepest pink that are sometimes even described as purple. It also comes in an all white form called Chelone obliqua ‘Alba.’ Chelone obliqua does offer one unique advantage over the other turtleheads: it is the latest blooming species. This one won’t start flowering until late August and continues for about four weeks into September. This later bloom time is especially valuable since the more popular summer bloomers like black-eyed Susan (Rudbeckia) and phlox are probably done.

So you might be thinking turtlehead would look great with some mums, right? Sure it would, but also consider some of the other late bloomers that would look beautiful next to the leaves and flowers of pink turtlehead. The blue or purple flowers of fall asters would make an excellent partner that grows from 1 to 3 feet tall. For a shorter blue bloomer, try the spreading plumbago (Ceratostigma plumbaginoides) whose electric-blue flowers are complimented by beautiful reddish-bronze fall foliage. The later-blooming monkshood (Aconitum napellus) has dark blue flowers on 4-foot spikes that resemble delphiniums from a distance. Check out other late bloomers like Joe pye weed (Eupatorium), hardy hibiscus, anemones, ornamental grasses, and fall-blooming crocus, to name a few. Keep in mind that turtlehead does produce a column of green leaves that is very visible when the plant is in bloom so you may want to soften it with a shorter flower or some complimentary beautiful leaves.

The cooler fall temperatures give us the perfect opportunity to spruce up our flower beds and begin planning for next year’s garden. Plants are less prone to transplant shock and will require less watering if cultivated in the fall. Plant some spring-blooming bulbs, think about trying some pansies, and don’t forget those mums. With these and the myriad of fall bloomers like turtlehead, all of us should have a spectacular September garden.

George Papadelis is the owner of Telly’s Greenhouse in Troy, MI.

At a glance: Turtlehead

Botanical name: Chelone (keh-LOW-nee)

Plant type: Perennial

Plant size: 2-3 feet tall; 1-1/2-2 feet wide

Habit: Upright

Hardiness: Zone 3 (zone 5 for Chelone obliqua)

Flower color: Pink, white

Flower size: 1-inch long

Bloom period: August-September

Leaf color: Green, dark green

Leaf size: 2-8 inches long

Light: Partial shade to full sun

Soil: Rich, moist soil

Uses: Areas in the garden that are continually moist or wet; bog garden; stream or pond bank

Companion plants: Asters, Joe pye weed, hardy hibiscus, anemones, ornamental grasses, plumbago

Remarks: Native plant. Provide adequate moisture if positioned in full sun.

Jonathon Hofley / Michigan Gardener
‘Rostrahlbusch’ switch grass in the summer.by George Papadelis

Ornamental grasses are an enormous group of plants whose popularity has altered our perception of perennial gardening. Before ornamental grasses, perennial purists struggled to find plants that provided winter interest and yet died down to the ground like the rest of the garden. Some gardeners rebelled and began using smaller evergreen shrubs. Others found solace with upright sedums like Sedum ‘Autumn Joy.’ Now, we have ornamental grasses.

Besides providing winter interest, grasses have fall color, move beautifully in the wind, and most have flowers that last long into the winter. They are extremely diverse too. Some grow in sun, others in shade. They may be as little as 1 inch tall or towering to 20 feet. It is more and more difficult to find an American garden without an ornamental grass.

Jonathon Hofley / Michigan Gardener
‘Heavy Metal’One of the most valuable ornamental grasses is switch grass (Panicum virgatum). This North American native has many of the attributes that make ornamental grasses popular. All switch grasses are clumpers. In other words, none of them are runners, which can quickly outgrow their allotted space and become a nuisance. Clumps of switch grass expand so slowly that they may not require dividing for 10 years or longer. When your clump eventually does grow too wide for your garden, you’ll need to dig up the entire crown to divide it. I have often equated dividing ornamental grasses to dividing the trunk of a tree. It’s easier with a chain saw, but an axe or hacksaw will do the trick. Basketball-size clumps will make great specimens within a year. The only maintenance your switch grass will require is a trim to about 6 inches in late March or early April. This allows the new growth to begin unencumbered by last year’s old growth.

All switch grasses have gray-green to blue-green leaves that turn gold to orange-red in fall and then fade to a wintertime shade of tan. The fall flowers emerge pinkish, reddish, or silvery and mature to a grayish white or brown. They will tolerate almost any kind of soil from wet to dry and from sand to clay. They prefer full sun but will tolerate light shade. Height can range from 3 feet to as tall as 7 feet. Needless to say, switch grasses are very versatile plants.

My favorite switch grass is ‘Heavy Metal.’ I first saw this plant from a tour bus at Longwood Gardens in 1992. I could not believe how stiff and upright this tight clump grew. It has metallic gray-blue leaves on a 3- to 4-foot tall plant. The purple flower sprays that emerge in late summer are followed by its bright yellow fall color. It’s spectacular. This one looks great in rows to form a short hedge or alone among perennials in any border.

Jonathon Hofley / Michigan Gardener
‘Dallas Blues’The largest switch grass you will find is ‘Cloud Nine.’ It can grow from 5 to 7 feet tall and has a more vase-shaped habit. Its light blue leaves hold up great in strong winds. It produces yellowish flowers in late fall that blush to tan for a winter show. The larger size of this switch grass makes it ideal as a visual barrier or background plant.

Panicum ‘Prairie Skies’ is a more upright grower like ‘Heavy Metal,’ only larger, to 5 or 6 feet tall. This exceptional, strong grower will usually produce substantial plants faster than other varieties. The powdery-blue foliage yields soft blue-gray flowers in fall.

‘Shenandoah’ is a shorter variety, only growing to 3 feet tall. Its other distinction is its deep red leaf color that starts in June and intensifies as the season progresses. In late summer, red flowers emerge that mimic the red leaf color. 

‘Dallas Blues’ bears very wide leaf blades of powdery blue. These unusual leaves grow on a 6-foot tall plant that develops 2-foot long, football-shaped flower heads of purple-blue that turn to a rich orange-tan by fall. The huge flowers are the most wind responsive of any of the switch grasses; the slightest breeze will send your garden into a long mesmerizing dance.

If you are using your switch grass in a perennial border, there are many late-blooming perennials that make fine companions. The showy stonecrop sedums (Sedum spectabile) include several varieties like ‘Autumn Fire,’ ‘Neon,’ and ‘Pink Chablis.’ These offer some interesting flowers as well as foliage for the autumn garden. Russian sage (Perovskia) offers lavender flowers above silvery foliage that grows 3 to 4 feet tall. Fall-blooming asters and boltonia are available in several colors and provide masses of late season flowers. 

Hines Horticulture
‘Shenandoah’Fall is a wonderful season to garden. Plants can be transplanted or divided with less stress and with less water. This is a perfect time to reevaluate your gardens and determine what changes should be made. Also, imagine your garden at wintertime to see if your landscape lacks winter interest.

Switch grass is a versatile plant that provides year-round interest with minimal care. With the companions mentioned above, ornamental grasses can be used to ensure a stunning display that lasts well into winter. Get to know this valuable group of plants; every American garden should have some.

George Papadelis is the owner of Telly’s Greenhouse in Troy, MI.

At a glance: Switch grass

Botanical name: Panicum virgatum (PA-ni-kum vir-GAH-tum)

Plant type: Perennial ornamental grass

Plant size: 3-7 feet tall

Habit: Upright or vase-shaped

Hardiness: Zone 5

Flower color: Soft purple, yellowish, gray-blue, pinkish red

Flowers: Airy clusters

Bloom period: Fall

Leaf color: Various shades of blue-green or gray-green

Light: Full sun to light shade; flowering and fall color are best in full sun

Soil: Tolerant of most types; from dry to wet, sandy to clay

Uses: Perennial bed, mixed border, hedge, specimen plant

Companion plants: Tall sedums, Russian sage, boltonia,  asters, mums

Remarks: Great year-round interest; fantastic fall color, from yellows to orange-reds, changing to tan in winter; easy to grow

www.monrovia.com
Bronzy fall color of northern sea oats.by George Papadelis

Ornamental grasses are one group of plants that draws a great deal of attention each fall when most of them produce their inflorescence. Consequently, gardeners re-evaluate the possibility of adding a grass or two to the landscape and more are planted in fall than any other time of year.

Ornamental grasses are an enormous group of plants that are usually perennial and typically provide attractive foliage in summer as well as winter. The four popular genera for sun are maiden grass (Miscanthus), switch grass (Panicum), fountain grass (Pennisetum), and feather reed grass (Calamagrostis). Some, like Carex (technically a sedge, not a grass) and forest grass (Hakonechloa), will tolerate shade. Northern sea oats produces beautiful seedpods and boasts tolerance of both full sun and part shade.

Eric Hofley / Michigan Gardener
The “flowers” are just emerging in this early July photograph.Park Seed
Tan winter color.Northern sea oats (Chasmanthium) is native to south, central, and eastern North America and is very hardy (zone 4). Like many other ornamental grasses, the dead foliage from the previous season should be trimmed in April to just a few inches above the ground. Spring weather will encourage the growth of bright green, grass-like leaves that are about an inch wide and 7 to 8 inches long. They develop on bamboo-like stems that typically grow from 2 to 4 feet tall. Northern sea oats’ crown is comprised of slow-spreading rhizomes that will only increase the plant’s size by a few inches per year. Plants that are well-established can be divided in spring.

Flat, green “flowers” develop on the arching stem tips from July through September. In fall, these become tan well before the foliage turns to copper in early winter. The flower heads are beautiful and the slightest breeze will send them dancing on the delicate stems from which they gracefully cascade. Snow and ice will add to their magnificence while they gradually shatter until spring.

The flowers do produce viable seed that can produce seedlings in spring. These are usually most prevalent when the soil is well-cultivated and kept quite wet. These volunteers are rarely a nuisance, but I do know of at least one gardener that has banned northern sea oats from her plant list. On the other hand, the northern sea oats in my garden has rarely produced seedlings.

Eric Hofley / Michigan Gardener
Sea green flowers shimmer in the breeze.www.monrovia.com
The summer to fall color change.Northern sea oats will thrive in full sun but will also tolerate almost total shade. In full sun, plants will grow slightly shorter and should not be allowed to dry out. Plants grown in shade or part shade are drought-tolerant once established. Try planting northern sea oats under larger trees where competition from tree roots may present a problem for other perennials.

The versatility of this plant makes it a welcome addition to almost any border planting. The bright green, narrow leaves are an excellent foil to contrast with broader foliage such as hostas, rodgersias, or perennial forget-me-nots (Brunnera). They may also be positioned near the finer foliage of astilbes or ferns. Almost any flower would be complimented by a backdrop of northern sea oats foliage. Each winter, when other perennials die back to the soil, northern sea oats stays up to provide the winter interest for which ornamental grasses are best known.

Great foliage, fascinating flowers, and almost a full year of interest make northern sea oats worth considering in your landscape. Best of all, its tolerance of sun or shade makes it suitable for use almost anywhere.

George Papadelis is the owner of Telly’s Greenhouse in Troy, MI.

At a glance: Northern sea oats

Botanical name: Chasmanthium latifolium (chaz-MAN-thee-um la-ti-FOH-lee-um)

Plant type: Perennial

Plant size: 24-48 inches tall and wide

Habit: Upright and clumping

Hardiness: Zone 4

Flower color: Sea green, maturing to bronze, then tan

Bloom period: July to September

Leaf color: Bright green, maturing to coppery gold

Leaf size: 1 inch wide, 7-8 inches long

Light: Sun to shade

Soil: Adapts to a wide range from moist to dry

Uses: Excellent backdrop for other plants and their flowers. Great 4-season interest: crisp green in the spring, dangling flowers in the summer, bronzy flower and foliage color in the fall, and tan tones in the winter.

Companion plants: Bold foliage like hostas, rodgersias, and perennial forget-me-nots (Brunnera). Fine foliage like astilbes and ferns. 

Remarks: Dangling, oat-like “flowers” shimmer in the slightest breeze. Very versatile, since it can adapt to both sun and shade, and moist to dry soils.

Jonathon Hofley / Michigan Gardener
‘QIS Lilac’by George Papadelis

The dog days of summer can certainly take a toll on the garden. Many plants are well-suited for intense heat while others struggle to maintain a flower for more than a few hours. One of the most heat-tolerant, and underused, annuals is Gomphrena. Its common name is globe amaranth and it is native to Central America. Once established in the garden, globe amaranth will tolerate temperatures in the hundreds about as well as any annual. It comes in several colors and plant height can vary from just 9 inches tall to over two feet. In my opinion, the best thing about globe amaranth is that it is relatively uncommon; plants will usually draw enough attention to conjure the occasional, “What is that?” I love hearing those words of wonderment from gardeners.

Gomphrena develops clover-like, round flower spikes that are almost 1 inch across. They make a great cut flower, and when dried, they will retain their shape and color indefinitely. They will thrive in any sunny position and will tolerate a broad range of soil as long as it is well-drained. Rain can make some annuals, like petunias, droop and flop. Gomphrena, however, stands strong and erect despite high winds or rain.

Sakata Seed America
‘Gnome White’The most popular series of gomphrena is the Gnome series. It is a dwarf variety that comes in about four colors including purple, pink, and white. It only grows about 9 inches tall and wide, and makes a great edging plant. In the annual border, this is a more interesting alternative to the common marigold or ageratum. It can also be a valuable addition to containers—especially those exposed to intense sun. Its compact size makes it suitable for sale in small packs just like other, more common bedding plants. It is also one of the more inexpensive annuals you can buy.

The taller gomphrenas are the ones that I find most interesting. They can be used as a unique addition to the perennial border since they are unfamiliar to many gardeners. One of my most pleasant memories of gomphrena came to me at Longwood Gardens. The variety ‘Bicolor Rose’ was planted in a vibrant mass along with several other unique annuals. It stands about two feet tall and the rose-colored flowers sport a spot of white at the tip. This is by far one of the most vividly-colored gomphrenas available. Try this variety in small groups in the perennial garden.

Julia Hofley
‘Strawberry Fields’Sakata Seed America
‘Gnome Pink’Other tall varieties include ‘Strawberry Fields,’ with strawberry-red flowers on strong upright stems to about 24 inches. ‘Lavender Lady’ has lavender flowers on 24-inch stems. Both of these varieties are getting harder and harder to find. The ‘Woodcreek’ series (also known as the QIS series) grows 24 to 30 inches tall and comes in seven colors including lavender, pink, orange, red, purple, rose, and white. Seeds for these are somewhat more available, especially amongst the cut and dried flower circles. Plants are sometimes sold in larger packs or small pots.

Whether you garden with perennials or annuals, gomphrena provides an interesting, easy to grow, heat-tolerant choice. Gardeners often overlook gomphrena in early spring when garden center plants can appear somewhat unimpressive. But once summer comes along, few annuals can provide such a unique flower and exceptional weather tolerance.

George Papadelis is the owner of Telly’s Greenhouse in Troy, MI.

At a glance: Globe amaranth

Botanical name: Gomphrena (gom-FREE-nuh)

Plant type: Annual

Plant size: 9 to 24 inches tall and wide

Habit: Upright clump

Flower color: Lavender, rose, red, pink, orange, purple, white

Flower size: 1 inch across

Bloom period: Summer

Light: Sun

Soil: Well-drained

Uses: Shorter varieties can be used as edging plants. Taller varieties can be used both in mass annual plantings or in perennial borders.

Remarks: Exceptional heat tolerance. Stands up to wind and rain also. Excellent cut flower; when dried, retains shape and color indefinitely.

by George Papadelis

In our quest for beautiful shade gardens, we often separate foliage plants from flowering plants. The attractive foliage of plants like hosta and ferns is used to provide season-long interest. This, along with an occasional shade-loving evergreen like boxwood or holly, make up the foundation of the garden. The list of flowering plants for shade is much longer than most people think. It includes, but is not limited to, primrose, monkshood, anemone, goatsbeard, plumbago, bleeding heart, turtlehead, foam flower, true forget-me-not, globeflower, perennial lobelia, waxbells, and many, many more. These should be sprinkled throughout the garden to provide occasional splashes of color from spring to fall. Some perennials, however, may have both beautiful leaves and beautiful flowers. This list includes lenten rose, lungworts, coral bells, bugbane, astilbe, barrenwort, bergenia and many, many more. These plants are very useful, especially where space is limited and a huge variety of plants is not practical.

Walters GardensAlchemilla mollis or lady’s mantle is another plant with a dose of both great leaves and great flowers. Its silky, olive green leaves are up to 4 inches across. This leaf color is unique and valuable for the shade but my favorite feature goes beyond their color. Lady’s mantle sparkles whenever water is on the leaf surface. With rain, morning dew, or the last watering, droplets of water bead like diamonds glowing in the shade. One definition of the word “mantle” describes a cloak-like garment. The plant’s common name is derived from its resemblance to the sparkling jewels of a “lady’s mantle.”

George PapadelisAs gardeners strive to combine leaves of different textures, lady’s mantle is especially valuable. The leaves have a rare color and feel that is perfect alongside contrasting plants. In the shade, the bold foliage of almost any blue, green, or bi-colored hosta looks perfect with the light green leaves of lady’s mantle. Ferns offer fine-textured leaves to contrast. In light shade, the sword-like, deep green leaves of Siberian iris look stunning near lady’s mantle. This is a particularly effective combination since the purple flowers of a Siberian iris like ‘Caesar’s Brother’ appear while lady’s mantle has begun bearing its chartreuse flowers in June.

Speaking of flowers, lady’s mantle also produces billowing sprays of small chartreuse flowers from June to July. Chartreuse has been and continues to be a very popular color in and out of the garden. Light colored flowers like these are especially bright in shady gardens. There are several other late spring and early summer bloomers available for creating a riot of early season color. Besides the Siberian iris mentioned above, many astilbes, perennial geraniums, campanulas, and coral bells would make great flowering companions. That said, companions are not mandatory; lady’s mantle has the merits to exist all by itself as a border around shrubs or a perennial garden. It may also be planted more densely and used as a groundcover.

Walters GardensLady’s mantle is versatile and easy to grow, preferring moist soil. This is often created when amending clay soils with organic soil amendments such as sphagnum peat moss, aged pine bark, or compost. It prefers part sun or part shade, but will also grow well in full shade and even full sun if it is not allowed to dry out. This plant can grow almost anywhere! Plants typically form mounds 12 to 18 inches tall which should be spaced about 18 to 24 inches apart. If plants are allowed to dry out or if growth becomes too leggy, the leaves may be cut back a few inches above the soil. New leaves will emerge, and in two to three weeks, a beautiful mass of lush foliage will reappear.

The flowers of lady’s mantle make great cut flowers that may also be dried for floral arrangements. Just like the garden, the chartreuse blossoms are stunning when combined with colors such as blue, violet, or rose.

I have always felt that this plant is terribly underused in American gardens. Its combination of beautiful foliage and flowers are often overlooked. In the gardens of England, where plants bearing mediocre foliage are rarely tolerated, this plant is quite popular. Try one in the sun or the shade. Plant it in combinations or as a border. Just add water and enjoy the sparkling and shimmering of your lady’s mantle.

George Papadelis is the owner of Telly’s Greenhouse in Troy, MI.

At a glance: Lady’s mantle

Botanical name: Alchemilla mollis (al-keh-MILL-uh MOLL-is)

Plant type: Perennial

Plant size: 12-24 inches tall, 18-24 inches wide

Habit: Mounding

Hardiness: Zone 4

Flower color: Chartreuse

Flower size: Clusters of tiny flowers

Bloom period: June-July

Leaf color: Olive green

Leaf size: 4 inches wide

Light: Shade to sun; provide plenty of moisture if in sun

Soil: Well-drained, prefers moist soil

Uses: Specimen perennial; shade plant combinations; edging plant

Companion plants: Hostas, ferns, iris, coral bells, astilbe, many other shade plants

Remarks: Water beads on the leaves for an amazing sparkle effect; leaves have a silky texture; beautiful foliage and flowers; can self-seed in the garden

Jonathon Hofley / Michigan Gardener
Clusters of blooms on long stalks add a delicate touch of color.

by George Papadelis

Tall verbena or Verbena bonariensis is one of those plants that no garden should be without. In a sunny location, its lavender purple flowers will sway in the wind atop 3 to 4 foot tall, wiry stems. It will bloom from spring until late fall since its excellent heat tolerance is followed by equally superb frost tolerance. It doesn’t require staking or deadheading and once established, it will rarely (if ever) require watering. And we’ve really only just begun to describe the merits of this terrific plant, which is treated as an annual in areas zone 6 or colder.

The flowers of tall verbena even drop seeds that will germinate the following spring and could be transplanted to create a repeat performance. It reseeds so prolifically that many gardeners treat this species as a “perennial.” I have had an infinite supply of Verbena bonariensis seedlings in between the pavers of my patio for seven years.

In our quest to create perennial gardens that bloom from spring to fall, we are typically burdened with examining the bloom times of countless perennial varieties. One convenient solution is to incorporate annuals with a “perennial look” that will bloom all season. Tall verbena is the perfect choice. And since it is grown from seed, it is usually available in economical flats as opposed to more expensive individual pots. Planting them in clumps of 6 or more gives the best effect. Space plants about 12 inches apart.

In summer annual beds, tall verbena is equally valuable. Annuals growing over three feet tall in shades of bluish purple are rare; only the tall annual aster (‘Matsumoto Blue’) and blue glory bush (Tibouchina) come to mind, and both of these can be hard to find. The small airy flowers of tall verbena are especially effective when contrasted with composite (daisy-type) flowers. Annual black-eyed Susan varieties (Rudbeckia hirta) offer several great choices in shades of yellow, gold, and orange. The electric orange flowers of the dwarf Mexican sunflower (Tithonia ‘Fiesta del Sol’) would also make a perfect companion. Even the red flowers of the common annual geranium (Pelargonium) look fantastic with tall verbena planted behind them.

Eric Hofley / Michigan Gardener
Verbena bonariensis is most dramatic when planted in drifts.

It wouldn’t be fair to not tell you about a Verbena bonariensis relative that I am sure you will also love. Many of you are probably familiar with the creeping or trailing verbenas that are usually hybrids of Verbena canadensis. These are usually grown from cuttings and perform beautifully in pots and beds. But there is another garden worthy species called Verbena rigida or rigid verbena. These also produce purplish-blue flowers, but the plants are only about a foot tall. Cultivars from cuttings have been available, but now there is a seed-grown variety called ‘Santos Purple.’ It has vibrant purple flowers on 10- to 12-inch tall plants. Its vibrant flowers can be seen from low-flying aircraft and my favorite part is that almost nobody can identify it. Even the most plant-savvy gardeners will ask, “What is it?”, “Is it a perennial?”, “Is it an annual?”. If you appreciate plants that are outstanding performers and that may potentially stump onlookers, then you must have Verbena rigida ‘Santos Purple.’

Both of these verbenas may be tricky to locate but they certainly offer traits that make them well worth the hunt. Try them in your garden and you too will soon be saying, “This is one of those plants no garden should be without.”

George Papadelis is the owner of Telly’s Greenhouse in Troy, MI.

At a glance: Tall verbena

Botanical name: Verbena bonariensis (ver-BEE-nuh bo-nar-ee-EN-sis)

Plant type: Treated as an annual (tender perennial; hardy to zone 7)

Plant size: 3-4 feet tall, 3 feet wide

Habit: Wiry and open

Flower color: Lavender purple

Flower size: Clusters 1 to 1–1/2 inches across

Bloom period: Summer to fall

Light: Sun

Soil: Well-drained

Uses: Annual bed, perennial border

Companion plants: Annual black-eyed Susans, tall cosmos, Mexican sunflower, tall dahlias, daylilies, and many more annuals and perennials.

Remarks:  Will reseed readily. Unwanted seedlings are easy to pull out. Although it is tall, can be used in the middle or even front of beds due to its open growth habit. Blooms appear to float in the breeze. Tolerates some frost.

Jonathon Hofley / Michigan Gardener
‘Alba’by George Papadelis

Heliotrope continues to be one of the most sought after annual plants every spring. Some varieties have intoxicating, vanilla-scented flowers that are irresistible, while others have beautiful blue, white, or lavender flowers. Its potent fragrance earned it the common name “cherry pie,” however, I have never heard anyone suggest that the scent even remotely conjures hints of any kind of pie. Heliotrope “flowers” are actually clusters of 1/4-inch blooms that develop in masses to form 4- to 8-inch heads. Among gardeners, the purple-blue varieties are the most desirable for their flowers, which combine so well with shades of pink, silver, or gold.

The rich, velvety flowers have become more and more popular in container gardens. Even the gardeners of the Victorian period recognized its value in potted combinations. Now that the huge, trailing leaves of golden sweet potato vine have made it into the container plant spotlight, heliotrope has been revealed as one of its perfect partners. Deep green heliotrope leaves and rich blue flowers above the golden leaves of sweet potato vine—wow! Add a trailing pink verbena or ivy geranium and you have a truly vibrant display.

Heliotrope is also a wonderful plant for bedding. One of my fondest heliotrope memories is a stunning combination I saw at the beautiful Butchart gardens in British Columbia about 10 years ago. Heliotrope was alternated in a mass planting with the variegated leaf geranium ‘Mrs. Parker.’ The cream and green leaves of the geranium shined beautifully below the bright pink geranium blooms and deep blue heliotrope flowers; it was breathtaking! In this example, even heliotrope’s dark green leaves were used to contrast with other foliage.

Johnny’s Selected Seeds
‘Marine’The most popular heliotrope is a readily available, seed-grown variety called ‘Marine.’ It is only slightly fragrant but has the navy blue flowers for which heliotrope is so commonly praised. It grows 15 to 18 inches tall. Because it is seed grown, it is usually the easiest for growers to produce and therefore the most inexpensive heliotrope to buy.

A cutting-grown variety called ‘Atlantis’ is rapidly becoming more popular. The flowers are about the same as ‘Marine’ but the plant seems to be more resistant to stretching. This makes it more desirable in situations where crowding (and thus stretching) might occur.

EuroAmerican Propagators
‘Azure Skies’The variety ‘Nagano’ is arguably the most fragrant blue heliotrope. The flowers emit a baby-powder scent that is strongest in the evening. It has the more compact growth habit of ‘Atlantis’ but sports deep violet-blue flowers.

In my opinion, the most fragrant variety is the white cultivar called ‘Alba.’ I know very little about aromatherapy, but I can’t imagine life without experiencing nature’s most pleasant scents. To remove a flower and enjoy its fragrance for even a few minutes is well worth the space required to grow this plant. White heliotrope’s vanilla scent is rivaled by few flowers; jasmine and English roses come to mind. This is an attractive plant but it is rarely grown for its beauty alone.

One of the newest varieties is a unique trailing version called ‘Azure Skies.’ Oddly, this one has no fragrance and grows more horizontally rather than upright. Its lavender flowers can be used to trail over the edge of a pot or it may be used for bedding as a low spreading mound about 8 inches tall.

Jonathon Hofley / Michigan Gardener
‘Azure Skies’All heliotrope prefer full or partial sun and all thrive in well-drained soils. Plants grown too cold or too wet can develop root rots. That being said, don’t allow plants to dry out. They are occasionally attacked by aphids but insecticidal soap can solve that problem.

Heliotrope can offer beautiful flowers as well as incredible fragrance. Once you have decided how you are going to use it, all you have to do is choose the appropriate variety. If you have never planted heliotrope and you don’t intend to have it in your garden, hopefully you will encounter it some day and experience its remarkable fragrance.

George Papadelis is the owner of Telly’s Greenhouse in Troy, MI.

At a glance: Heliotrope

Sunny Border Nurseries
Coreopsis ‘Heaven’s Gate’ by George Papadelis

Many gardeners covet long-blooming perennials. Perennials that bloom for more than six weeks are particularly valuable in gardens with limited space. Fewer varieties can be used to provide the garden with color from early spring until late fall. Within a given genus of perennials such as Salvia, Veronica, or Geranium, there may be various varieties with a broad range of flowering periods. Similarly, tickseed or Coreopsis is a genus that contains some of the most popular long-blooming perennial varieties. All Coreopsis attract butterflies and are easy-to-grow plants derived from American native species.

The most popular species is Coreopsis verticillata or thread-leaf coreopsis. This species contains several varieties, all of which have fine, “thread-like” foliage. The variety “Moonbeam” was chosen by the Perennial Plant Association as the Perennial Plant of the Year in 1992. It grows 12 to 18 inches tall, 24 inches wide, and produces a myriad of pale yellow, daisy-like flowers. It begins blooming in early June and will continue to flower for about 10 to 12 weeks. Removing the spent flowers can further prolong flowering. This practice, however, is seldom considered worthwhile due to the profuse flowering of the typical ‘Moonbeam.’

Eric Hofley / Michigan Gardener
The pale yellow flowers of Coreopsis ‘Moonbeam’ echo the leaves of this variegated iris.The variety ‘Crème Brulee’ has much larger and brighter pale yellow flowers than ‘Moonbeam.’ It grows slightly taller at about 18 to 24 inches tall. It has a thread-leaf that is more coarse than ‘Moonbeam,’ so it can be more prone to floppiness. Plant ‘Moonbeam’ and ‘Crème Brulee’ with summer-blooming blue perennials such as veronica and salvia.

Two other thread-leaf coreopsis are relatively easy to find. ‘Golden Showers’ produces golden yellow flowers shaped like those of ‘Moonbeam,’ but is a much more upright grower. It grows about 24 inches tall and 18 inches wide. Flowering begins in June and persists well into fall. The variety ‘Zagreb’ is bushy and shorter, with bright yellow flowers on 12- to 18-inch plants.

Jonathon Hofley / Michigan Gardener
Coreopsis grandiflora ‘Sunray’ The shortest species is Coreopsis auriculata, growing only 6 to 10 inches tall. The variety ‘Nana’ is long-lived and begins to bloom earlier than other coreopsis. Flowering begins in May and continues until July. The single orange-yellow flowers develop over a low carpet of rounded leaves. This one is especially well-suited for use as edging or a rock garden plant.

The tallest species is Coreopsis grandiflora. These produce the largest flowers within the genus. They grow from 1 to 3 feet tall and are some of the longest-blooming perennials available. Flowering usually begins in June and continues until September, especially if spent flowers are removed. The drawback is that they are likely to bloom themselves to death; the Coreopsis grandiflora varieties (except for ‘Flying Saucers’) can put so much energy into fall flower and seed production that the weakened plant may not overwinter. The removal of flower stems and seed pods beginning in early September will encourage the development of a strong crown that is more capable of winter survival.

Jonathon Hofley / Michigan Gardener
Coreopsis ‘Limerock Ruby’ Several varieties of Coreopsis grandiflora exist but these are some of the most noteworthy. ‘Goldfink’ is the shortest Coreopsis grandiflora at only 8 to 10 inches tall. It produces several 1-1/2-inch, single gold flowers. ‘Baby Sun’ (aka ‘Sonnenkind’) is another short variety at 12 to 20 inches tall. It forms a mound of single golden-yellow flowers about 2 inches across. ‘Early Sunrise’ is a former All-America Selections winner and one of the few perennials to receive this distinction. It produces semi-double golden flowers on plants that are 18 to 24 inches tall. ‘Sunburst’ is the tallest Coreopsis grandiflora available at 30 to 36 inches tall. It has larger gold flowers on longer stems and is the best cultivar for cutting.

‘Sterntaler’ offers a unique 2-inch gold flower with a mahogany-brown circle around the center. It grows 16 to 18 inches tall. The variety ‘Tequila Sunrise’ is the only Coreopsis available with interesting green and cream variegated foliage. It produces single gold flowers over plants growing 16 to 18 inches tall. This relatively new cultivar has proven to be somewhat less hardy than others so take precautions such as improving drainage and providing additional winter protection.

Perhaps the most effortless and dependable Coreopsis grandiflora is “Flying Saucers.” This one has sterile flowers that cannot waste energy on seed production. That means it can spend more energy on flower production and gathering strength for overwintering. Golden yellow flowers are produced well into fall and deadheading is far less necessary. Its profuse flowering makes it suitable for use in containers too.

Pink varieties of coreopsis come from the species Coreopsis rosea. The best variety with all pink petals is Coreopsis rosea ‘American Dream.’ Ironically, this plant was the Perennial Plant of the Year in Europe several years ago. It yields several 1-inch, rose-pink daisies with a tiny yellow eye. It grows 8 to 16 inches tall and will bloom until fall if deadheaded. ‘Sweet Dreams’ has large, distinctly bi-colored flowers that combine soft pink petals with a large raspberry pink center. It can grow floppy in more fertile soil, but pruning away the top half will make plants more compact and bushy.

Heritage Perennials
Coreopsis grandiflora ‘Flying Saucers’ A while ago, an exciting new ruby-red coreopsis called ‘Limerock Ruby’ was introduced. Millions were sold all over the world and unfortunately, it became evident that ‘Limerock Ruby’ was not hardy in the colder zones (it is only hardy to about zone 7). Since then, ‘Limerock Ruby’ has tragically become almost impossible to find in most garden centers. It blooms all summer and produces hundreds of flowers. This color is very rare in the flower color palette; only a few plants such as chocolate cosmos and Scabiosa ‘Ace of Spades’ offer blossoms of a similar hue. This plant is certainly worth the effort to track down and perhaps an increase in consumer demand will keep this great annual from disappearing.

Since the demise of ‘Limerock Ruby,’ another selection at least partially fills the void: ‘Heaven’s Gate’ is the deepest pink coreopsis available. It is truly hardy to zone 5 and flowers all summer long.

Coreopsis offers a huge range of different flowers and foliage on plants that display exceptionally long bloom times. In large, English style borders that abound with daisies, lilies, gayfeather, bee balm, and daylilies, coreopsis is a wonderful addition. In smaller gardens, where only a few plants can get squeezed in, high performance perennials like coreopsis are a must.

George Papadelis is the owner of Telly’s Greenhouse in Troy, MI.

At a glance: Coreopsis

Botanical name: Coreopsis (kor-ee-OP-sis)

Common name: Tickseed

Plant type: Perennial

Plant size: 8-36 inches tall, 8-24 inches wide

Habit: Clumping

Hardiness: Zone 4 or 5

Flower color: Pale yellow, golden yellow, pink, deep pink

Flower size: 3/4 to 2-1/2 inches across

Bloom period: Summer to early fall

Light: Sun

Soil: Well-drained

Uses: Perennial border

Companion plants: Blue-flowering perennials like salvia and veronica; daisies, lilies, gayfeather, coneflowers and daylilies.

Remarks: Can be short-lived (a few years). Deadhead spent blooms to prevent seed production, which prolongs the life of the plant.

Jonathon Hofley / Michigan Gardener
Plectranthus argentatusby George Papadelis

Gardeners continue to covet beautiful foliage in every aspect of their landscapes. More than ever, we are likely to look beyond the flowers and learn to appreciate the foliage; flowers come and go, but foliage endures. In perennial gardens, for example, fancy-leaved versions of old favorites are very popular. Trendy perennials like the Jacob’s ladder (Polemonium) ‘Stairway to Heaven,’ phlox ‘Becky Towe,’ and bugbane (Cimicifuga or Actaea) ‘Hillside Black Beauty’ are adorned with much more decorative foliage than their green-leaved relatives. Some popular annuals like coleus and sweet potato vine are used purely for their gorgeous leaves. Plectranthus is also grown primarily for its gorgeous leaves, like its relative coleus. This enormous genus is also blessed with fragrant leaves and a huge range of uses.

Most of the ornamental plectranthus have the unique ability to tolerate either sun or shade. The durable leaves rarely shed and will withstand strong winds. Plectranthus is also very drought tolerant and even quite tolerant of rough handling.

Jonathon Hofley / Michigan Gardener
Plectranthus fosteri ‘Marginatus’The genus is most easily divided into three distinct groups: 1) upright foliage, 2) trailing foliage, and 3) attractive flowers. Among the upright forms, we have the silver-leaved Plectranthus argentatus. Silver foliage is almost always desirable amongst other foliage and flowers. These prefer sun and produce large silver leaves with a felt-like texture and slightly serrated edges. They may grow up to two or three feet tall, making them ideal for larger plantings or containers. Pinching may be necessary to control height and encourage branching. I have seen Plectranthus argentatus used in the center of a large container in combination with the upright blue angelonia, pink trailing petunias, and white trailing Nierembergia—a beautiful and durable combination.

It should be noted that almost every plectranthus is grown from cuttings. That means you will typically pay a bit more for a single plant (compared to seed-produced plants). In 2005, however, there was a breakthrough in plectranthus. Some seed companies began offering a new Plectranthus argentatus grown from seed called ‘Silver Shield.’ It branches better than the one grown from cuttings and the height and spread are about 24 inches. Seed-grown plants are typically a bit more affordable since they are often available in flats.

Jonathon Hofley / Michigan Gardener
Plectranthus fosteri ‘Green on Green’The other upright forms are Plectranthus fosteri ‘Marginatus’ and Plectranthus fosteri ‘Green on Green.’ The former has green and white variegated foliage and the latter has green and gold variegated foliage. The leaves are similar to Plectranthus argentatus, but are sometimes much larger. The thick, scented leaves on upright stems weave beautifully amongst the flowers and leaves of other annuals or perennials. Both of these can be very quickly grown into standards: stake the stalk to the desired height, then repeatedly pinch to create a terminal poodle or globe shape. These prefer sun or part sun.

The trailing varieties will thrive in sun or shade. They can be used for bedding or simply used as a more interesting vinca vine replacement. For trailing silver leaves, try Plectranthus x ‘Silver Foil.’ Plectranthus madagascariensis ‘Variegatus’ has bright green and white variegated leaves that will trail down and continue to maintain a nice mounded habit. It is striking next to bright colors like petunias or with the white flowers of Bacopa.

Jonathon Hofley / Michigan Gardener
Plectranthus oertendahlii ‘Uvongo’One of the most interesting trailing forms is Plectranthus oertendahlii ‘Uvongo.’ It hugs the ground and produces beautiful silver and green patterned leaves. The best part is the showy purple-pink undersides that reveal themselves just enough to give ‘Uvongo’ delicate rose accents. In more sun, the stems turn purple and so does the new growth. Try this one in a container interplanted with euphorbia ‘Diamond Frost’ (tiny upright flowers) and the blue trailing flowers of lobelia ‘Big Blue.’

Another beautiful trailing plectranthus is ‘Troy’s Gold.’ This one is also quite short, only growing to about five inches tall. Leaves are brightly variegated green and gold with some deep purple veins. The stems and leaf undersides on ‘Troy’s Gold’ are also purple. Plant this one with any purple or gold flowers for optimum impact.

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Plectranthus ‘Zulu Wonder’The common Swedish ivy (Plectranthus australis) is another trailing plectranthus. Its glossy, dark green leaves can cascade as far down as 3 to 4 feet. Plants persist effortlessly in hanging baskets and can thrive in either sun or shade. Interiorscapers test this plant’s durability again and again in thousands of restaurants, offices, and mall plantings.

Among the flowering varieties, there are a few that are somewhat available. ‘Zulu Wonder’ has lavender-blue flowers, while ‘Lois Woodhull’ bears beautiful flower spikes of bluish-rose and white from summer until fall. It only grows about 10 to 12 inches tall and has thick, green leaves. For a unique, late-blooming annual, look for ‘Mona Lavender.’ Its stunning late summer display consists of large, lavender-flecked blossoms on contrasting dark stems. The leaves are a glossy dark green on top and burgundy underneath. It can exceed 18 inches in height when provided with ample space.

Consider trying the beautiful foliage or flowers of a plectranthus—they offer a delightful alternative to mainstream annual bedding plants.

George Papadelis is the owner of Telly’s Greenhouse in Troy, MI.

At a glance: Plectranthus

Common name: Swedish ivy

Plant type: Annual (tender perennial)

Habit: Upright and trailing varieties

Plant size: Upright varieties: up to 3 feet tall and wide; Trailing varieties: up to 12 inches tall

Leaf color: Silver, gray-green, green and white variegated, green and gold variegated, green

Leaf size: Rounded, 1 to 4 inches long and wide, depending on variety

Light: Sun to shade

Soil: Well-drained

 Uses: Upright varieties: large containers, annual and perennial borders; Trailing varieties: front of containers, hanging baskets, wall plantings

Companion plants: The many foliage colors compliment a wide array of annuals and perennials.

Remarks: Grown for its foliage, like coleus. Foliage weaves nicely amongst other plants. Upright forms can be easily trained into standards. Size of upright varieties can be controlled with pinching. Silver-leaved varieties prefer more sun.