Archive for the spring tag

Plant Focus: Viola

March 3, 2020 • Leave a Comment

*Viola cornuta* (Photo: Jonathon Hofley / Michigan Gardener)

by George Papadelis

In the spring, the earliest bedding plants to appear at your local garden center are violas and pansies. These are usually available in flats and look similar except violas have smaller flowers than pansies. So, what is the real difference between violas and pansies and is this the same “violet” that has spread all over my friend’s yard? As a matter of fact, the plants referred to as “violas,” “pansies,” and “sweet violets” are all in the same group of plants, namely the genus Viola.

*Viola cornuta* ‘Jersey Gem’ (Photo: White Flower Farm)

Pansies are the result of crossing different species of violas. These “hybrids” (called Viola x wittrockiana) have flowers 2 to 4 inches across and include an incredible range of colors including white, black and practically every color in the rainbow. These plants will tolerate freezes and frosts, so gardeners can plant them as early as April 1 here in Michigan. They will flower profusely all spring and if old flowers are removed, they will most likely continue through the summer. The cool fall will encourage more flowering, which often lasts until the winter holidays. In our climate, pansies planted in a protected area usually return one more season for another performance, although somewhat less spectacular. Protected areas include the south side of the house and the cooler east side.

The smaller-flowering viola (Viola cornuta), sold in flats every spring, has evolved greatly. Several series such as the “Princess” series and the “Sorbets” have introduced new colors and color combinations that rival the closely related Johnny jump-up (Viola tricolor). Violas planted in our climate last one or two seasons. Just like pansies, spent flowers must be removed to encourage flowering through the hot summer.

Viola

Botanical Name: Viola cornuta (vy-OH-lah kor-NEW-tah)
Common Name: Violet, horned violet
Plant Type: Hardy annual/tender perennial
Plant Size: 5-10 inches tall
Flower Color: White, purple, violet, yellow, maroon
Flower Size: 1-1/2 inches wide
Bloom Period: Spring to fall
Light: Partial sun to sun
Soil: Well-drained, moist
Hardiness: Zone 5
Uses: Areas that are partially sunny, yet moist
Remarks: Remove spent flowers to encourage blooms through the summer

The dangerous member of this group is Viola odorata or “sweet violets” which are often just referred to as “violets.” These are very perennial, produce fragrant, small flowers in the spring, and may spread everywhere if you let them. Like violas and pansies, sweet violets produce seeds which may germinate and produce more plants. However, sweet violets also send underground stems called stolons in all directions, which may be difficult to find and remove. This invasive nature makes it an excellent groundcover or a wildflower in a naturalized site. Sweet violets have also been planted for as long as gardens have existed. The flower market in Athens, Greece sold sweet violets as early as 400 B.C. Its fragrance has been used by the perfume industry for centuries and is still being used by some today.

All members of the genus Viola produce edible flowers. Chefs all over the world use these showy blossoms as an attractive garnish, especially on salads. The blossoms also make great cut flowers and are among the most popular flowers for pressing. Members of the Viola family grow best in partial sun but full sun can be tolerated. High temperatures and drying out will cause stress, so keep the soil moist and cool if possible.

*Viola cornuta* ‘Cuty’ (Photo: White Flower Farm/Michael Dodge)

Gardeners looking for something different may want to try the purple-leafed viola (Viola labridorica) for its attractive foliage and fluorescent purple flowers. Other violas such as Viola koreana even have attractive silver patterned leaves. The bird’s foot violet (Viola pedata) is easy to identify because the leaves look just like a bird’s foot.

From a naturalizing habit to being self-contained, the genus Viola is so diverse that every gardener is sure to have a spot for at least one variety!

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

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

March 10, 2018 • 7 Comments

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.

What is the best time of year to reseed bare patches in the lawn?

July 8, 2011 •

What is the best time of year to reseed bare patches in the lawn? Can it be done in the spring? If so, please provide tips.

In Michigan, late August to mid-September is the ideal time to seed all grass types. The soil is warm yet the air has cooled down from summer temperatures.

However, most homeowners don’t want to go through the summer with a spotty lawn. Mid to late spring can be a suitable time to reseed bare patches in the lawn, after frost warnings are lifted. The soil temperature needs to be at least 50 degrees for grass to germinate at a normal rate. Waiting longer gives the soil more time to warm up to about 60 degrees and improves your success rate. Given sufficient moisture, the seed will germinate quicker with the added warmth, depending on the seed type.

Do not apply any spring lawn weed killers or crabgrass preventers. If you do, grass seed will not sprout or the seedlings will be killed along with the weeds and crabgrass.

Prepare the patches by removing any weeds. Scratch up the soil with a heavy dirt rake or cultivator. Mix up 1/3 sphagnum peat moss with 2/3 good garden soil to get a light, spongy texture. Add 1-1/2 cups of balanced organic fertilizer per bushel of soil making sure the fertilizer has a high phosphorous (P) content to stimulate root growth. Most “starter fertilizers” are high in phosphorous. Spread this mixture over the bare spot until it is slightly higher than the surrounding soil level. Gently work it into the scratched-up soil originally there.

Use a seed type similar to the existing grass unless it was the wrong kind to start with. Buy new seed. The percentage of seed that will germinate from old seed drops drastically with each year. Also avoid bargain seed. They generally contain the largest amount of annual or rough-bladed grasses.

Hand cast your seed and don’t be stingy. About 15 to 20 seeds per square inch is good. Bury the seed 1/8 to 1/4 inch into the soil by dragging a spring rake over the area with the tines inverted. Do not tamp so hard that you compact the soil. You want water to soak in easily. It is also helpful to cast some of the new seed to the outside of the repaired spot. This helps the new grass blend into the neighborhood!

Grass seed needs both moisture and warmth in order to sprout. Cooler temps will make it germinate slowly. But if there is a lack of moisture it won’t do a thing. Once the seed has germinated, avoid walking on the repaired spots to give the new plant roots time to dig in and acclimate. If you seed with a blended mix, the different types will germinate at different rates. So when you see green sprouts, continue to provide water for the later varieties to germinate.

Related: Keeping your lawn green

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Viola