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    Save the Date: Perennial Plant Society’s 30th Plant Sale is April 4, 2020, 9 a.m. – 1 p.m. at the new Expo 3 Building at The Fairgrounds Nashville. Here’s where you can find the newest varieties of perennials, shrubs, vines and annuals from local growers, along with long-time, never-fail favorites, ready for spring planting. Learn more at the PPS website.

     

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Roses may be at risk for fungal disease

My rose bush is developing little black spots on some of the leaves. What’s causing this, and what can I do about it?

Yellow rose

Roses may develop diseases that affect the foliage.

For questions on roses, I always go to the helpful experts at the Nashville Rose Society, and their Web site. It looks like there are at least two fungal diseases that cause black spots on the leaves of roses: one appropriately called black spot, and the other, anthracnose. You can tell the difference by looking at the edges of the spots. Black spot has the feathery margins, which give rise to some of its other names: leaf blotch or star sooty mold.

Both make a rose look really bad for awhile, which is why people who are serious about growing fancy, beautiful roses stick to a rigid schedule of spraying. Fungicides are to ward off the ugly fungal diseases, pesticides to keep away chewing and sucking bugs.

Both blackspot and anthracnose overwinter on the plant and develop during a cool, moist spring. The best way to minimize the risk of developing diseases is with preventive maintenance: Clean up dead leaves and decaying matter around rose bushes, prune out diseased canes, make sure the rose bush is in a place that has good air circulation, and water in the morning, to give the foliage plenty of time to dry during the day. Fungicides, applied on a regular schedule in early spring, can help prevent infection.

Prune to preserve the sweet scent of mock orange

Our two mock orange shrubs are full of blooms right now, but they haven’t been pruned in many years and they are very tall and lanky with a lot of dead wood, and look terrible the rest of the time. When can they be shaped up or pruned?

Philadelphus - mock orange

Mock Orange

The flowers of the mock orange shrub last only a week or two in late spring in USDA Hardiness Zone 7a (where The Garden Bench calls home), but they can provide a stunning show, and the fragrance, which is said to resemble orange blossoms, is delicate and sweet.

Those flowers bloom on the previous year’s growth, so you should prune the shrubs right after they finish blooming this year, which allows time for new growth to mature and bloom next spring.

If the shrub is in really bad shape but still vigorous, you can actually do a rejuvenation pruning, removing the oldest stems at ground level to encourage vigorous new growth. Information from the National Gardening Association suggests cutting out about a third of the stems. Pruning the shrub every year encourages it to grow more densely.

In general, mock orange (Philadelphus is the botanical name) grows best in full sun but can tolerate a little shade. It does well in most types of soil, as long as it has good drainage. Mock orange is good to use as a background shrub or a specimen plant in the landscape. If you’re considering a new shrub, be sure to plant it where you can enjoy that sweet, though fleeting, fragrance.

Book giveaway – winners!

southern gardeners handbookLast week we announced a book giveaway – two copies of Southern Gardener’s Handbook by Middle Tennessee author Troy B. Marden. Commenters Rhonda and Amanda were picked in random drawings, and they’ll receive copies of the book from the publisher, Cool Springs Press. Thanks for your comments!

Zinnias for summer – and a Book Giveaway!

I love seeing zinnias in a summer garden, and want to plant them in my yard this year. Is it too late to grow them from seeds?

ZinniasYou’d get that great summer zinnia look a little sooner by planting bedding plants, if you can find them, but early May is not too late to plant zinnia seeds. In fact, they get off to a better start if you sow seeds after the soil has warmed, as they sprout and grow quickly.

Sow the seeds in a prepared garden bed (good garden soil in full sun) about ¼-inch deep. Keep the bed moist, and once they’re up, thin the plants to at least six inches apart. This is important to provide good air circulation around the plants; a bed planted too thickly may be more susceptible to powdery mildew when summer’s humidity sets in.

Then, just wait a few weeks for them to start blooming. Butterflies will love them, and you’ll be able to cut flowers for summer bouquets from the time they start blooming until frost knocks them down. The more you cut, the better and bushier the plants will be.

There are dozens of zinnia varieties, tall and short, and a range of colors. Most of the familiar forms are common zinnia, Zinnia elegans, but gardeners who wish to avoid the powdery mildew problem may want to try Z. angustifolia, or narrow-leaf zinnia, which grows in a mounded form. The flowers resemble miniature daisies, and the plant blooms from early summer to frost.

A fun fact that I found at the Rodale’s Organic Life website: when zinnias, which are native to Mexico, were introduced in Europe, the flowers were referred to as “everybody’s flower” because they were so common and easy to grow.

Book Giveaway! Southern Gardener’s Handbook by Troy Marden

©Troy B. Marden

©Troy B. Marden

If you ask Troy Marden about the best plants for a garden, he’ll most likely talk about soil.

“That may not be the answer you expected and it’s usually not the answer most people want to hear,” he says. “People want to plant pretty flowers, trees and shrubs.

“But if you don’t start with your soil – amend it, feed it, nurture it – the results will be lackluster.” That’s especially true here in the south, where we often try to coax a garden out of heavy, wet clay.

Troy is one of the Mid-state’s favorite go-to garden experts, so we listen to what he says. He’s passing along more of his garden knowledge in a new book, Southern Gardener’s Handbook, published this spring. Besides his thorough lesson on soil and how to make it better, he offers his ideas for best practices on watering, fertilizing, understanding microclimates, sun and shade, compost and “greener ways to garden.” This is followed by three hundred full-color plant profiles, organized under ten plant categories from annuals to vines.

“I wrote this guide as comprehensive, but approachable,” Troy says. “Interesting enough for the more seasoned gardener, but easy enough to understand for those who might be getting their hands dirty for the first time.”

southern gardeners handbookThe Giveaway: Here at The Garden Bench, we are giving away two copies of Southern Gardener’s Handbook from the publisher, Cool Springs Press.

Leave a comment at the end of this post about your favorite May blooms – or just say “Count me in!” Respond by 6 p.m. Friday, May 15, 2015, and your name will go into a drawing to win one of two copies of Troy Marden’s Southern Gardener’s Handbook.

Small space, big returns: It’s possible to grow edibles and ornamentals even if you don’t have a plot of soil that you can call a garden. In Saturday’s Tennessean, master gardener Mary Boyd discusses several ways to garden in small spaces. Master Gardeners of Davidson County is getting ready for its annual Urban Garden Festival on May 16.

May garden tips & tasks

May is a busy and beautiful time in the garden. Here are tasks and tips to keep you busy this month.

Week 1

Azalea The Garden Bench

Prune azaleas shortly after they bloom.

Plant your summer kitchen garden with warm-season vegetables: tomatoes, peppers, squash, okra, beans. Water newly planted garden beds well, and keep them moist as seeds sprout.

Foliage left from spring-flowering bulbs – daffodils, tulips and so forth – can be cut down if it has turned brown.

If you need to prune azaleas, do it now; don’t wait any longer, or you risk cutting off next year’s flowers, which will begin to form soon.

Set out bedding plants of favorite summer annuals: petunias, begonias, annual salvia, cleome, cosmos, celosia, snapdragon, zinnia.

Find a comfortable spot for houseplants that will spend summer outdoors, protected from too-harsh sun and strong wind and rain.

Week 2

Hellebores The Garden Bench

Dig and divide hellebores

Use mulch in perennial and annual beds and borders to keep weeds in check, and to retain moisture in the soil.

A cluster of aphids on tender new growth of plants can be washed away with a strong spray of water from the hose.

Container gardens dry out quickly in hot weather, so if your “garden” is a collection of pots on the deck or balcony, they need to be watered frequently.

Divide hellebores. Dig up as much of the root ball as possible and gently separate the roots. Replant right away, or share with friends (reminding them to plant as soon as possible).

When you mow, set the mower to cut high, removing only about a third of the height of the grass to keep it healthy. Don’t shear the lawn.

Week 3

Cut flowers The Garden Bench

Cut spring flowers to enjoy indoors.

There will always be unwanted plants (sometimes known as weeds). Pull or dig them out of garden beds when they are small, but especially before they form seeds. Weeds are easier to root out after watering or after a rain, when the soil is moist. Annual weeds that haven’t gone to seed can be tossed into the compost.

As summer approaches, make sure spring-planted trees and shrubs continue to get enough moisture. Provide about an inch of water a week — by hose or sprinkler if it doesn’t rain.

Enjoy the late spring bounty of flowers indoors. To help them last longer, cut flowers and foliage early in the morning and place them in water right away.

Grass clippings make good mulch, but allow them to decay before you use them on beds and borders.

Watch for spider mites on roses and other shrubs if the weather turns hot and dry. A strong spray of water on the undersides of leaves every few days can keep them under control.

Week 4

Thyme The Garden Bench

Thyme and other herbs are at their peak just before they bloom.

Many herbs are at their peak just before they bloom. Harvest them to use fresh, or preserve them by drying or freezing to use later.

As perennials flower and fade, cut the dying blooms. This will encourage the plant to bloom longer.

Divide irises after they finish blooming. Cut the leaves to about five inches, then lift the tubers with a spading fork. Separate the rhizomes and cut off damaged portions, then replant the rhizomes close to the soil surface.

Hummingbirds are welcome summer guests in the garden, visiting flowers and nectar feeders. If you provide feeders, change the nectar every day or two and clean the feeder thoroughly. Standard nectar recipe: 1 part sugar to 4 parts water; boil for five minutes, and allow it to cool before filling the feeder. No red food coloring needed.