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  • May garden tips & tasks

    GARDEN EVENTS IN MIDDLE TENNESSEE

    May 20: Master Gardeners of Davidson County Urban Gardening Festival, 9 a.m. - 4 p.m., Ellington Agricultural Center Demonstration Garden. Free admission. www.mgofdc.org; on Facebook at www.facebook.com/mgofdc.

    June 10: Middle Tennessee Daylily Society show and sale, Ellington Agricultural Center’s Ed Jones Auditorium, 440 Hogan Rd. in Nashville. Sale open at 10 a.m.; show opens to the public at 1 p.m. To learn more about the Middle Tennessee Daylily Society, visit www.middletndaylilysociety.org.

    It’s time to plant those tender herbs and vegetable transplants, such as basil, dill, tomatoes, green peppers, hot peppers, eggplant.

    If tomato transplants are already too tall and leggy, you can plant them on their sides and cover the long stems with soil. The stem tips will turn upward, and the buried stems will sprout roots.

    Sow seeds of bush beans and pole beans, cucumbers, sweet corn, melons, okra, field peas, pumpkin, squash and zucchini. Follow the directions on the seed package for planting depth and spacing. Vegetables grow best in full sun.

    Cut the faded blossoms of peonies. Fertilize the plants lightly in late spring or early summer.

    Remember the basics of watering: morning is best, so plants’ leaves have time to dry before evening. Lawns, perennial borders and annuals like to have 1 – 1½ inches of water per week.

    Many indoor plants enjoy a summer vacation outdoors. Give them a cool, shady spot in the yard, and don’t forget to water them.

    Prune thyme frequently so it will stay full and green in the center.

    Weeding is easiest after a rain. If the ground is too dry and you need to weed, soak the bed first with a hose or sprinkler.

    Whether they’re growing in the ground or in pots on the porch, pinch the tips of geraniums from time to time to encourage them to branch out and to produce more flowers. Geraniums in pots benefit from regular feeding with a water-soluble fertilizer.

    Remember that mulch can be a gardener’s best friend. Pine straw or composted leaves are good alternatives to hardwood mulch.

    Harvest herbs as they reach their peak. Dry small leaves on a screen, hang small bunches of long-stemmed herbs in a warm, dry room out of the sunlight.

    Plants growing outdoors in containers dry out quickly when it’s hot. Check them daily, and water as needed.

    Don’t go near hydrangeas with the pruning shears unless all you’re cutting is dead branches. If the bigleaf hydrangeas look like they’re not going to bloom, it could be that the buds were nipped in a late cold snap, or the plant was pruned too late last year.

    As the flowers of Shasta daisies begin to open and then to fade, keep them clipped off. This prolongs the blooming season of daisies (and most other annuals and perennials), and keeps the plants looking better, as well.

    Watch for aphids on shrubs and perennials. A strong blast of water from a hose will remove many of them, or spray with insecticidal soap.

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Japanese maples stand out in winter

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‘Japanese Sunrise’ is a favorite cultivar for many home gardens because of its multi-colored winter bark. Photo by S. Hamilton, courtesy UTIA.

On a snowy, gray day, what plant can add a bit of cheer in the landscape? Japanese maples, says Sue Hamilton, director of UT Gardens. Each month, the University of Tennessee Institute of Agriculture highlights a “Plant of the Month,” and Japanese maples get the honor for January 2017. Several selections exhibit brilliant bark color when the temperature falls – bright red or orange or yellow or coral pink, “They make quite a show in the winter landscape,” she says.

Sue says they’re also easy trees to maintain. Depending on the cultivar, the size can range from 6 feet to 25 feet tall, but many are in the 10 – 15-foot range, which makes them a good addition to almost any landscape.

“Foliage is a lime green in spring, darkening in color as summer approaches,” she says. “Fall foliage is either a bright, showy shade of yellow or a fusion of red, orange and yellow.” They do best in moist, well-drained soil that is slightly acidic. The grow in partial shade but bark coloration will be best when the tree grows in full sun, and young twigs and branches will be more color intensive that the tree trunk itself, she explains. Continue reading

Remove English ivy from trees

The large trees around our home are covered with English ivy. Is there a way to keep it from growing up into the limbs of the trees?

P1040778 (2)English ivy growing up into trees (and another invasive creeping vine, wintercreeper euonymous) are most evident now, when the trees are bare. It’s this time of year when you can see just how quickly and how thickly those vines – which are evergreen — can climb into the tree canopy. Left to grow, English ivy vines can engulf the tree within a few years.

Once the vines have grown up into the limbs, there is no quick and easy way to get them down. The vines will have grown stout trunks that continue to reach up and branch out as they cling to the bark. The National Park Service, which has an interest in keeping English ivy from displacing native flora on public lands, suggests several methods for controlling the vine. It likely will require a combination of manual, mechanical and chemical methods. Continue reading

Replace landscape plants in fall and winter

We have lost many of the shrubs around our home. How late can we replant all of the landscaping around our residence? Is November too late?

ball burlap treesIf you are planting shrubs and trees, November is actually a good time to replant. Trees and shrubs planted when they are dormant have an easier time establishing good root systems before they begin actively growing again next spring. They will need to be watered at planting time and throughout the season, but not as often as you would have to provide water in spring or summer.

Here are general guidelines from UT/TSU Extension for planting balled-and-burlapped and container-grown trees and shrubs:

-Choose your location and begin by digging a wide hole, two or three times the width, but no deeper than the height of the root ball.

-Handle the trees carefully before you plant. Never pick up or carry a tree by its trunk, especially a balled-and-burlapped tree, due to the weight of the root ball. If they can’t be planted right away, water the trees well and place them in an area away from direct sun.

-Water a plant in a container before you take it out of the pot. After you remove the plant, cut any roots that circle the ball of soil (if the roots and soil don’t come out easily, cut the plastic away from the root ball. Don’t pull the plant out by its trunk). Use a sharp knife to make two or three vertical cuts, and gently loosen the ball to expose more roots to the soil.

-Place the plant in the hole so that the top of the root ball is an inch or two above the soil line. Remove any nails or rope lacing and cut away the burlap, leaving the burlap at the bottom of the root ball. If there is a wire basket, cut as much of it away as you can without disturbing the root ball.

– Backfill the hole with the soil that was removed from the hole, watering when the hole is about half full and again after you finish backfilling. Rake over the soil to even it out with the ground, and cover the area with 2 or 3 inches of mulch (keeping the mulch away from the shrub’s trunk.

-Don’t forget to provide water to newly planted shrubs and trees if the weather is dry.

Prune crape myrtle without committing ‘crape murder’

I have developed my crape myrtles into tree forms. Every year I have to cut back the suckers that grow from the base of the trees at ground level. Is there anything I can do to eliminate the suckers?

Crape myrtleThe suckers that grow from the ground around crape myrtles can be the result of improper pruning. If you top the plants every year (and garden experts sometimes refer to this as “crape murder”) they respond by sending up shoots from the base.

There are many sources for information on pruning crape myrtles, but one good one comes from the Virginia Cooperative Extension of Virginia Tech and Virginia State University. Their suggestion:

Prune crape myrtles as you would any other tree or shrub – by cutting back to a bud, a side branch or a main stem, giving consideration to the ultimate shape of the plant. If you need to cut off only part of a branch, cut above an outward facing bud or side branch. If you need to remove an entire branch, cut just outside the branch collar on the stem, where the branch is attached.

Don’t make random cuts in the middle of a branch or stem. Topping a crape myrtle – or any tree, for that matter – can lead to stem decay and more dead branches. It also encourages the growth of weak shoots at the top of cut stems, which can become top-heavy with flowers and break in a strong wind.

The Virginia Cooperative Extension notes that re-suckering can sometimes by suppressed by applying naphthalene acetic acid after the suckers are pruned. Crape myrtles that are given too much fertilizer may also produce suckers, and have fewer flowers. They advise not to fertilize unless a soil test indicates the need to do so.

The best time to prune crape myrtles has passed for this year. Do the job in late winter or early spring, before new growth begins.

 

This weekend: Beautiful bonsai

bonsai2Bonsai expert Owen Reich invites garden enthusiasts to the Nashville Bonsai Society’s Regional Bonsai Expo July 11 – 13 at Cheekwood Botanical Garden. Reich, Jim Doyle and Young Choe are guest artists, and there will be more than 50 bonsai displays, along with workshops, exhibits and vendors.

The photo above is of a Swamp Rose (Rosa palustris) that Reich collected in Tennessee and trained as a bonsai. “There will be a number of bonsai on display this year created from trees and shrubs native to the United States, as well as high-end bonsai imported from Japan,” he says. The stand in the display was made in Chattanooga by Tom Scott, and the container is a 250 – 300 year-old Chinese container called a Kowatari Shirogochi Pot.

The picture is just a sample of the unique and unusual bonsai on display this weekend. Complete details here.

A sticky hackberry situation

QUESTION: We have a question regarding one of our large hackberry trees. It’s covered with little white flying bugs and the leaves have a sticky residue. What causes this and is there something that we can do about it?

Asian wooly hackberry aphids are a nuisance, but won't harm the trees.

Asian wooly hackberry aphids are a nuisance, but won’t harm the trees.

The bugs you are seeing are called Asian wooly hackberry aphids, and they seem to make an appearance about this time every year. They feed exclusively on hackberry trees, and like all aphids, they feed by piercing the leaves and extracting the juice. The sticky residue is what they excrete after feeding on the leaves, a substance called honeydew. Another byproduct you may notice is a black mold that grows on the honeydew, which is called sooty mold.The aphids apparently do not do enough damage to harm the tree, they are just a nuisance, mostly in late summer and early fall when their population grows due to the many generations that have been produced. If it’s a nuisance you can’t tolerate for some reason, there is a systemic insecticide product that is said to be effective in controlling aphids, but it would not do anything to solve this year’s population. There are several brands available, but the main ingredient is a chemical called imidacloprid, and it should be applied to the ground around the tree in early spring, where it will be taken up via the tree’s vascular system into the leaves.

Not much, then, can be done about this year’s population of hackberry aphids. Hose off the cars, the deck, the lawn furniture and anything under the trees that are sticky from the honeydew, and take comfort in the knowledge that they are a temporary annoyance, and will be gone in a few weeks.

For trees and shrubs, prime planting time

QUESTION: I have a hydrangea that I bought at a nursery last spring, and it’s still in the pot it came in. Is it too late to plant it?

Fall is a good time to plant hydrangeas and other woody ornamentals.

Fall is a good time to plant hydrangeas and other woody ornamentals.

I’m sure every gardener has, at some point, bought sturdy plants in the spring, but somehow never got around to putting them in the ground (I know I have!). You can be sure that your hydrangea will be happier in the ground than it will be if it has to struggle through the winter in a plastic pot.

In fact, fall and winter are good times to plant woody ornamentals, when they are dormant and have fewer energy requirements. They still need water, but require less than they would in spring going into the hot summer. In fall, new trees and shrubs can begin to establish a strong root system and be ready to begin new growth next spring.

Here are general guidelines from UT/TSU Extension for planting container-grown trees and shrubs:

-Choose your location and begin by digging a wide hole, two or three times the width, but no deeper than the height of the root ball in the container.

-Water the plant before you take it out of the pot. After you remove the plant, cut any roots that circle the ball of soil (if the roots and soil don’t come out easily, cut the plastic away from the root ball. Don’t pull the plant out by its trunk). Use a sharp knife to make two or three vertical cuts, and gently loosen the ball to expose more roots to the soil.

-Place the plant in the hole to that the top of the root ball is even with the soil line or an inch or two above it, and backfill the hole with soil and water again. Rake over the soil to even it out with the ground, and cover the area with 2 or 3 inches of mulch (keeping the mulch away from the shrub’s trunk.

-Don’t forget to provide water to newly planted shrubs and trees if the weather is dry.
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Evergreens turning ever-brown

QUESTION: We are seeing many evergreen trees — Leyland cypress and others — with big sections of brown limbs. Is that due to the drought? Or is there some other problem affecting the trees?

The drought this summer plays a big part in the browning of Leyland cypress, but it’s not the whole story. Alan Windham, at UT Extension’s Soil, Pest and Plant Center says the branch dieback is the result of a one-two punch: drought and seirdium canker, a fungus that appears on branches or stems and in branch axils and causes the branch to die. “I’ve seen more damage this month than I can remember in several years,” Windham says.

I found a good description of seirdium canker at the Web site of North Carolina State University’s Plant Pathology Extension: The cankers are brown or purple sunken patches on the bark, and may be accompanied by a flow of resin. Affected branches may be scattered randomly throughout the tree; they turn a reddish-brown color, in striking contrast to the green, healthy foliage. The fungus can be spread by splashes of rainwater or water from sprinklers, or it can travel from branch to branch on unclean pruning tools.

There are no chemicals recommended to control the canker. Brown branches should be pruned and destroyed as soon as possible. Prune at least an inch below the canker, and sterilize the pruning tools between cuts by dipping them in rubbing alcohol or a solution of 1 part chlorine bleach to 9 parts water. Plants that are severely affected should be removed and destroyed. Watering by drip irrigation during drought can help prevent problems, Windham says.

Upright arborvitae are also having trouble due to the drought. Windham explains: Plants have different strategies to survive: some plants sacrifice older leaves to protect new shoots; some have waxy leaves, some plants roll their leaves or close up to prevent water vapor from escaping.

“Then you have plants like arborvitae, where it’s all or nothing. It’s as if the plant is saying, ‘We’re going for broke. Everything survives or nothing survives.’ Well, this strategy didn’t work out too well for many arborvitae I have seen.”

In this case, the only solution is to remove the dead trees and start again.