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Archive for the Ask MG department

Can Easter lilies be planted outside in southern Michigan?

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The heady fragrance of traditional Easter lilies (Lilium longiflorum) or Madonna lily (Lilium candidum) is never forgotten once experienced. Both are true members of the lily family. They grow about 1-1/2 to 3-1/2 feet tall in full sun in rich, evenly moist but well-drained soil. Because you are asking about planting outside in zones 5 and 6, you’ve probably heard numerous stories of how people have a whole garden full of “Easter lilies” that they’ve planted every year and successfully had them grow and bloom repeatedly.

That being said, a few words of caution and qualification go with those success stories. The lily hybrids of Lilium longiflorum are not usually considered a garden plant, being normally hardy to only zones 7 to 9. Consequently they are grown primarily in pots here, and nurseries force them in bloom so their buds burst forth in time for the Easter celebration. Remember this observance moves on the calendar annually, from as early as mid-March to as late as mid-April. The bulb is not mysteriously intelligent; it has just been manipulated by greenhouses to bloom at the desired time.

That being said, there is a cultivar called ‘Mount Everest’ that bears fragrant white trumpets and can be grown in the ground in zones 5 to 8. If you were fortunate enough to receive or purchase a lily with an identification tag, you may know if you have that plant or another named cultivar. Or, if you in fact have a Madonna lily, it will tolerate temperatures down to 25 degrees. Unfortunately most Easter lilies rarely get tagged because they are either forced in a greenhouse or shipped in from warmer regions and are not hardy to our zones that deal with frozen soil in winter.

However, if you would like to attempt to save it in the ground, choose a sheltered, sunny spot that is well-drained. Many times we have microclimates around our homes, especially near the house foundation, that mimic a zone or two warmer than our overall region. If that warm, dry place is close to an often-used walkway, all the better to enjoy the fragrance.

Plant the bulb about 6 to 8 inches down, as you would any of the hardy summer-blooming Asiatic or Oriental lilies. Add about a tablespoon of granular bulb fertilizer to the planting hole. Evenly moist but well-drained soil at the site, especially in winter, cannot be stressed enough. You can leave the foliage intact to help feed the bulb naturally until the leaves completely brown out. Apply a heavy blanket of shredded leaf mulch to the planting area to minimize winter temperature fluctuations.

If there isn’t a place in your yard that suits these special conditions, try letting the foliage die back with the bulb in the pot. Let the soil dry out, and then lift the bulb, checking for soft spots. Make sure it is dry and soil-free. Store the bulb wrapped in a paper bag in a cool dry place until the following February. You are mimicking the winter dormancy of its native habitat. Then you can pot it up with a well-draining soil mixture, keeping the soil moist but not soggy. Put it in a warm, sunny window away from drying heat vents and watch the bulb come to life.

Selecting plants for the evening garden

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I work all day and I am home only in the evenings. What flowers can I plant that will bloom at night and maybe even have fragrance?

An evening garden relies heavily on flowers that are white or light-colored so they will be visible even on a moonless night. Moonlight really illuminates the flowers and foliage, making the garden at night a different, magical experience. Nighttime flowers are exactly that—they bloom in the evening and remain closed during the daytime. These flowers often give off beautiful, fragrant scents, and the evening dew helps intensify those scents. Even if some of the flowers do bloom during the day, it is in the evening when they give off their headiest fragrance. Scent in the evening somehow carries farther than in the daytime, and it is this scent that attracts the nighttime moth pollinators.

There are quite a few plants that are suitable for evening gardens. Dusty miller’s leaves range from gray-green to silvery white. Trumpet and oriental lilies give off a heady smell. Heliotrope, which also comes in a creamy white that will shine at night, gives off a sweet vanilla scent. Alyssum has tiny white flowers and a honey-like scent, making it good for pots and the front of borders. Impatiens also comes in white, and when planted in a pot or on a deck, it can reflect light from the moon to create a beautiful effect. Peonies, roses and hydrangeas also come in bright whites and yellows and will add much beauty to the evening garden.

A favorite flower for an evening garden would be moonflower. These are annual vines that thrive in hot weather. It is similar to the morning glory except it blooms at night. Plant it close to your seating area so you can watch its large, white blossoms unfold in minutes in the early evening—spectacular! The almost pure white blossoms are fragrant all evening and just illuminate the garden.

Pink evening primrose is another good choice. It has four satiny, heart-shaped petals that form open cups with long stamens. When they open, the blossoms are a soft, clear white that fade into pink as the flowers mature. Their scent is reminiscent of a blend of honeysuckle and lemon custard. Nicotiana is another sweet-scented flower whose blossoms close in the daytime but open in the late afternoon and fill the air with jasmine-like aroma. Make sure to include fragrant hostas like H. plantaginea, ‘Royal Standard,’ ‘Honey Bells,’ ‘Tokudama Aureonebulosa,’ ‘Sweet Standard,’ and ‘Fragrant Bouquet.’

Bright foliage is another way to create evening beauty in the garden. Lamium is a beautiful groundcover with two-toned, white-centered leaves. Lamb’s ears are another good plant for evening foliage. Other plants worth considering are white-flowering shrubs, and annuals like dame’s rocket, tuberose, petunia and dianthus.

To give your evening garden an extra dimension, add some solar or candle lights here and there, plus try a water feature. Even if it is a small fountain, the sound of water really makes the evening even more magical. The visual impact of bright whites, the scents of flowers and the sound of the evening all combine to make the evening garden a place that will calm and sooth the spirit.

Groundcover that handles foot traffic

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I would like to grow a fast-growing groundcover that is very short and can withstand being walked upon often and still look good. Are there any out there that survive in zone 4 and thrive in part sun to full shade?

First, you need to determine what “walked upon often” means in terms of frequency. Is it “light” (once or twice per day), “moderate” (about 6 times a day), or “heavy” (dozens of times per day)? The frequency of the daily traffic narrows the choices to those that can survive that impact. Second, you are limited in the number of hours of sun, and you want a fast grower. You may have to combine two or three species to satisfy all your criteria. Also remember that even though they are groundcovers, they will have tiny flowers that will call out to various insects and pollinators. An unwary bare foot could come away with an unpleasant sting.

Light traffic. Tiny creeping sedums make great groundcovers. They need little water and attention. They do grow moderately quickly if given the sunny section of your path. Sedum requieni will take the heaviest foot traffic in this group. Bugleweed (Ajuga) varieties do well in sun or shade. Ajuga “Chocolate Chip” is a small, tight groundcover whose leaves are a bronzy chocolate color. 

Moderate traffic. Try creeping Jenny (Lysimachia) varieties. They prefer moist areas with partial shade. Their leaves are the size of dimes and they spread by runners. Wherever a leaf node lands, it will root. So it can rapidly fill in any given area. It can be considered invasive if not judiciously checked. L. nummularia ‘Aurea’ has chartreuse gold foliage and is often sold as a trailing plant for containers. L. japonica ‘Minutissima’ has super tight evergreen foliage. However, it is a slow grower. So combining two varieties of Lysimachia would give visual interest as well as quick coverage. Also take a look at Kew wintercreeper (Euonymus fortunei ‘Kewensis’). It is evergreen all year, tolerates shade, harsh soil conditions, and averages 2 inches in height. This is a very durable groundcover, but coarser in texture than the lysimachias.

Heavy traffic. Thymes and Irish moss are the most durable choices. Thyme is a great survivor, tolerating being walked on many times a day. Look for creeping thyme (Thymus serpyllum) or woolly thyme (Thymus pseudolanuginosus). Both will tolerate dry soil, are present spring through summer, and can handle zone 4 conditions. They tend to do better with more sun, but will tolerate partial shade. Irish moss (Sagina subulata) will form a very dense mat and is especially effective when combined with stepping stones. It likes moisture, prefers soil low in fertility, and enjoys dense shade. Homeowners often find it in their lawns when turf becomes thin and compacted.

Ask MG: How do I grow Cleome from seeds?

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I saved the seed from my cleome plants last year. When I put the seed out this year, it grew a lot of giant weeds. What happened?

Cleome vary in height from 2 to 5 feet; some are bushy, others are stalky. The cleome you see most is spider flower (Cleome spinosa or hassleriana), or hybrids or cultivars that have the Cleome spinosa in their parentage. This plant can look beautiful in the back of the border, especially in a cottage style garden. In a more formal garden it can look out of place or weedy. Some people find the scent offensive, which is skunk-like. It produces many seeds and can spread like wildfire. To prevent this, remove flowers as soon as they have formed seed pods. The plant will make new flowers and usually keeps blooming all summer.

If your cleome from last year was not a true species but a hybrid—which are labeled with a “cross” symbol (X) in the name—the seeds will either be sterile or the plants that grow from them won’t “come true.” Instead the plants will resemble one or more of its ancestors. The only way to make sure your cleome will be the color and size that you want is to buy seed from a specific species, hybrid, or cultivar.

Ask MG: What are some suggestions for deer-resistant plants?

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My subdivision has been taken over by deer. As I plan next year’s garden, please suggest some perennial flowers or shrubs that deer will not eat.

If deer are hungry enough, they eat just about anything. This answer will include deer-resistant or rarely-damaged varieties and resources to check out more. You might first consider deterring deer from entering your garden. One suggestion is a motion-sensitive sprinkler, called the ScareCrow, which is available at many garden centers. It sprays a shocking blast of water about twenty feet, scaring away deer. Move it periodically or the deer “learn” the pattern, but it is harmless and waters your plants. Be sure to turn it off if you have guests! Also, deer do not like prickly items, many fragrant plants, and footing areas that make noise or feel unstable.

Here are some plants that deer tend to avoid. Bulbs: allium, daffodil and autumn crocus. Herbs: dill, purple coneflower, lavender, sage, tansy, thyme. Shrubs: boxwood (Buxus sempervirens), American holly (Ilex opaca), and Japanese pieris (Pieris japonica). Trees: paper birch (Betula papyrifera) and Colorado blue spruce (Picea pungens). Perennials: yarrow, columbine, bergenia, bleeding heart, oriental poppy, Russian sage, coneflower (Rudbeckia), lambs’ ears (Stachys byzantina), and yucca. Groundcovers: sweet woodruff, dead nettle (Lamium maculatum), plumbago (Ceratostigma plumbaginoides), and pachysandra.

Deer-Resistant Plants for Homeowners is a 2008 publication by Michigan State University, Bulletin E-3042. Contact your county extension office for a copy (www.msue.msu.edu). Also try the book Deerproofing Your Yard & Garden by Rhonda Massingham Hart (Storey Publishing).

What is the difference between own-root and grafted roses?

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What is the difference between own-root and grafted roses? Is one better than the other?

Own-root roses are produced by rooting and growing the cuttings of desired varieties. The types produced by this method often include Antiques, Flower Carpet, Meidiland and many Shrub varieties. Most own-root roses do not need ground level protection in winter once they are established.

Budded (or grafted) roses are produced by inserting a bud of a desired variety onto a vigorous rootstock. The types produced by budding include Hybrid Teas, Grandifloras, Floribundas, Climbing and English varieties, as well as a few from the Antique and Shrub groups. Budded roses should be planted with their swollen bud union 1 to 2 inches below the surface, plus have winter protection each year to help them survive our cold Michigan climate.

Few rose varieties are produced using both methods, so the question of one method being “better” than the other really does not apply. Since the propagation method relates to the type of rose, your choice is really determined by the rose producers and their experience of which one works best for that particular variety.

Ask MG: Why is my Purple smoke tree not smoking?

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I have a purple smoke tree that is about 9 years old. It is a large, healthy tree, but it has never “smoked.” Every spring it is full of blossoms, then when other smoke trees are beginning to smoke, the blossoms on this tree shrivel and die. I have tried watering it more, I have tried watering it less. Any ideas? J.W., Ann Arbor

Although smoke tree or smoke bush (Cotinus coggygria) requires well-drained soil and full sun, it is quite adaptable to different soil conditions. A large shrub or small multi-stemmed tree that can grow to 15 feet tall, it can work as a background plant for the mixed border or as a single specimen plant. Its claim to fame is the cloud of pinkish gray “smoke” that covers the plant in the summer. The effect is the result not of flowers, but of tiny pinkish hairs on the small fruits that occur in large clusters. There are some popular cultivars with purple leaves and darker flower clusters, such as ‘Royal Purple,’ ‘Velvet Cloak,’ and ‘Nordine Red.’

While smoke bush is relatively easy to grow, it can use some help in the early stages of development. For a new plant, avoid planting in waterlogged or poorly draining soil. For an existing plant, dig a dozen holes with a crowbar at the drip line that are a foot deep. Fill these holes with 5-10-10 fertilizer. This should be a one-time application. Early spring is best but it can be any time. It isn’t necessary to repeat this unless the smoke bush is not thriving in later years. Woody plants are going to be happier if you don’t overdo it. Annuals, tropicals and turf are heavy feeders, but over-fertilizing perennials and woody plants can force them to produce more stems and leaves than they want to, which can lead to unnecessary stress. Once established in the landscape, shrubs and trees adjust to the nutrients in the soil and often don’t want too much extra pampering. Avoid fertilizing (directly or indirectly) with high nitrogen (lawn) fertilizer; nitrogen promotes stem and leaf growth at the expense of flower production.

If your tree is planted in the lawn, remove the grass in at least a 6-foot diameter area around your tree. Mulch the area (do not pile mulch up against the trunk) and water infrequently: a good soaking once per week is much better than multiple small waterings. Smoke bush is drought-resistant and overwatering can result in few or no blooms, and makes it more susceptible to disease. Woody plants need watering less frequently than tender annuals, lawn, or herbaceous plants. Most established trees and shrubs can go weeks without supplemental watering except in very hot or windy weather.

Ask MG: Growing apples in Michigan

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What are the causes of apples dropping from trees prematurely while still very small? Is malathion a safe, readily available treatment for apple trees after the petals fall? Can you recommend a book for growing apples in Michigan? D.E.

Premature fruit drop can be natural, environmental, or pest-related and it takes some careful observation to determine which category yours falls into. An early apple drop before the fruit has matured may be the result of an overproduction of fruit by the tree. The plant simply cannot support the continued nourishment for such a vast number. Profuse flowering and extensive pollination can cause this overproduction beyond what the tree can sustain. Subsequently, it “sheds” a few pounds of excess fruit to conserve energy in a natural thinning process. Some fruit tree growers will even manually thin a tree to increase the quality and size of the final product, beating the tree to the punch.

Premature fruit drop can be environmentally stimulated by unfavorable conditions like frost, excessive heat or cold, or drastic changes in humidity. Living in Michigan, any of those conditions are quite possible in the flower to fruit cycle. Since symptoms can also be soil-related, it is important to check your regularity of watering and that the proper nutrition is offered the tree at the root zone. A soil test geared toward fruit tree production would zero in on those nutrients and their correct proportions. You can obtain a soil test kit from your county’s MSU Extension.

Another environmental occurrence is herbicide drift. Never apply herbicides in windy or dead calm conditions. Dead calm is often associated with a phenomenon known as temperature inversion. Contrary to popular belief, spraying under such conditions can actually increase drift distance. The culprit spray may be several yards away, making it difficult to pinpoint the source.

Pest-related fruit drop occurs much later in the season, when the fruit is very near maturity. So insect pests are probably not the reason for your premature drop.

As for the application of malathion, a readily available insecticide for homeowner use, proceed with caution. Make certain you correctly identify the pest, that the insect pest exists on your apple trees and that it is doing damage before arbitrarily applying any insecticide. Malathion is particularly effective against leafrollers and codling moths, which can damage apples, and must be applied at specific intervals. All label instructions and cautions should be followed to the letter if applying it yourself. A better choice would be to contact a certified arborist for an accurate diagnosis and treatment. Oftentimes beneficial insects can be eliminated from nature’s cycle in the homeowner’s fury to protect their plants.

For Michigan apple growing information, contact the your county’s MSU Extension and obtain how-to bulletins on tree fruit. For a nominal cost, you will get targeted, science-based information on Michigan climate, the best apple varieties, and proper techniques to successfully grow apples in Michigan.

Ask MG: Does fertilizer have the potential to repel deer?

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I am looking for a deer repellent and found out some people have used Milorganite fertilizer to repel deer. Have you heard of that, and what would be the advantages and disadvantages?

According to Milorganite, “There is information in the common press and on web sites that state Milorganite is a deer repellent. Milorganite is not registered with the EPA as a deer repellent yet.” Additionally, a customer service representative for Milorganite said, “We do not use this statement in our marketing, since it has not yet been proven scientifically.”

Milorganite received its name in a contest in 1925, derived from MIL-waukee ORGA-nic NIT-rogen, named by McIver and Son of Charleston, South Carolina. It is the solid microbes produced from a water treatment facility in Milwaukee, Wisconsin. It is described by Cornell Waste Management Institute (Fact Sheet 2006, by Ellen Z. Harrison, Director) as “treated sewage sludge or biosolids.” They claim it ends up as a heat-dried pellet (thus killing viral and bacterial pathogens) and not compost. Milorganite literature assures it is tested daily and is safe for use as a fertilizer around children and pets. They also claim it is organic, however according to Cornell Waste Management Institute, “Sewage sludge products are not allowed for use in certified organic agricultural production according to the U.S. Department of Agriculture regulations.”

Cornell also conducted testing for the product as a deer repellent. Their 2005 preliminary findings indicated it reduced deer damage in summer when alternate foods were available, but not in winter or spring.

The benefit of Milorganite is its use as a slow-release nitrogen fertilizer containing 6 percent nitrogen, 2 percent phosphorus and 4 percent iron. It won’t burn plants if too much is applied because it has virtually no salt content like other fertilizers. It is recommended you keep the product away from children and pets and to wash hands immediately after handling.

Transplanting hydrangeas

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I realized that my 3-year-old ‘Nikko Blue’ hydrangeas are planted in full sun and need to be moved. Can I transplant them to another location and, if so, when should that be done? J.K., Canton

Don’t panic and brandish a shovel at your ‘Nikko Blues’ just yet! Your “full sun” could have some ameliorating conditions that dilute the intensity of the light. Although hydrangeas are natural woodland plants, they can handle full sun if moisture is consistent and they are protected from midday sun, the real scorcher of the day. That said, their preference is dappled shade. That can be achieved even with a high tree canopy. Greater consideration should be given to desiccating wind patterns and protection from those.

If you still feel you need to transplant your shrubs, fear not. A hydrangea’s root ball in most cases is quite compact and generally comes out of the ground with a good quantity of soil adhering to its roots. This enables transplanting with a minimum slow down in growth. At three years old, yours should still be a size that you can handle easily. Late spring is the best time to plant or transplant your hydrangeas. Keep as much soil around the root balls as possible. The top of the root ball should be just below ground level in its new home. Make sure you put a little leaf compost in the bottom of the hole and spread out the roots into the new space.

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