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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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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

Prune clematis for a better show of blooms

Question: Our spring-blooming clematis vine has grown tall and seems very healthy, but it blooms mainly at the top. The bottom six feet has very few blooms and not much foliage this spring. Can you tell me why?

clematis 2Clematis flowers clambering over a sturdy trellis or other support are a lovely sight each spring. When this woody flowering vine gets too top-heavy, with all the flowers at the top and bare stems at the bottom, the problem has to do with pruning – or lack of it. Early-flowering clematis blooms in spring from buds formed last season. Plant experts recommend pruning it each year to help the plant produce the maximum number of flowers. The time to do that is as soon as you can after it finishes blooming to allow time for new growth to produce flower buds for next year.

Horticulturists writing for a fact sheet from Ohio StateUniversity say that sometimes you can cut back into older wood of old, neglected plants to encourage new buds to break. The vines are most likely tangled, so when you prune, make cuts carefully, and train the stems to cover the maximum are on their support.

Note also that there are other varieties of clematis that bloom a bit later, on new growth, and those varieties should be pruned in the winter.

In general, here is what clematis needs to thrive: Loose, fast-draining soil that is high in organic matter, and regular water. Gardeners like to say that clematis prefers to have its head in the sun and its feet in the shade, so provide a thick layer of mulch to keep the roots cool. You can also plant a ground cover such as mondo grass around the base of the clematis vine.

Don’t let English ivy ‘leap’

English ivy has covered a chain link fence along our property line, but it’s also getting into a garden bed a climbing up a tree. How can I control it?

English ivy is good for covering ugly fences; not so great when it climbs up into trees.

English ivy is good for covering ugly fences; not so great when it climbs up into trees.

Gardeners have a saying about English ivy: “The first year it sleeps, the second year it creeps, the third year it leaps.” It can be slow to get started, but once it gets going, it quickly leaps out of bounds.

If you are using English ivy to cover an otherwise unsightly feature or to control erosion on a slope, the Southern Living Garden Book suggests trimming the edges back with hedge shears or a rugged mower two or three times a year. Ivy growing up a fence or wall can also be sheared with a hedge trimmer to look neat.

Early winter is a good time to remove ivy that is growing up into trees. Garden expert Judy Lowe (who has penned several garden how-to books for our region) suggests cutting the vine at the base with loppers or a pruning saw. In the spring, the dead vine may fall out of the tree, or you may need to cut and pull down the dead portions.

 

Periwinkle: Bigleaf can be a big problem

QUESTION: This vine (in the photo) is growing behind the boxwoods in front of our house. I’ve never seen it before. Is this something I should keep or get rid of?

Variegated Vinca major (bigleaf periwinkle) is a major pest plant.

Get rid of it, if you can. It looks like variegated bigleaf periwinkle (Vinca major), and left to grow on its on, will scramble and snake its way across everything in its path. This plant, considered an ornamental groundcover by some, was brought here from Europe more than three centuries ago.

It has pretty little blue or lavender pinwheel flowers in spring, but that’s not enough reason to keep it around. According to the Tennessee Exotic Pest Plant Council, the vine has crept in to open and dense canopied forest, forming mats and “extensive infestations” by vines that root at the nodes. They consider it a “significant threat” in the state, and note that it’s also considered invasive in several other southern states, and in California and the Pacific Northwest.

If your “infestation” is still fairly small, I suggest pulling it up, roots and all, if you can. You’ll probably have to pull it several times before it’s all gone. I never recommend chemical controls, but you can read what TNEPPC suggests here.

One of the nice features about the Tennessee Exotic Pest Plant Council’s web site is that they suggest alternatives for the invasive plants you might be considering for your landscape. So, instead of periwinkle, TNEPPC recommends using these natives:

Wild Blue Phlox (Phlox divaricata) and Creeping Phlox (Phlox stolonifera). Both attract bees and butterflies. Creeping phlox does best in the more acidic mountains of East Tennessee.

Several grass-like sedges make good groundcovers for shady places: Seersucker sedge (Carex plantaginea) has puckered light green leaves. Silver sedge (Carex platyphylla) has slightly puckered, light blue-green foliage. Blue wood sedge (Carex flaccosperma) has silvery blue foliage and can do well in wetter sites.

Partridgeberry (Mitchella repens) is a small creeping vine with tiny, glossy, deep green leaves, pairs of white fuzzy flowers in early June, and bright red berries. It grows in shade, and needs acid soil. Birds like it.

Golden Ragwort (Packera aurea [ Senecio aureus ]) has dark, evergreen foliage that colonizes as a groundcover and yellow flowers in early spring. Attracts bees and butterflies.

Marginal Woodfern (Dryopteris marginalis) is an evergreen fern that likes shade and moist soil.

 

The trouble with winter creeper

QUESTION: A vine with dark green, oval leaves and thick woody stems is growing up through the middle of my shrubs. It seems to grow all year. What a nuisance! How can I get rid of it?

Winter creeper euonymus grows in sun or shade, can cover slopes, fences, trees, and is hard to get rid of once it's established.

It sounds like you are describing winter creeper euonymus, an evergreen that can sprawl along the ground (or on slopes, where it can help control erosion) or it can climb and attach itself to trees, walls and other surfaces with aerial roots.

You may see it described as “tough” or “aggressive,” and come to understand that to mean you’ll have a hard time getting rid of it. Indeed, it’s a non-native invasive plant, brought here from  the other side of the world in the early part of the last century. The Tennessee Exotic Pest Plant Council lists it as a “lesser threat,” but a threat nonetheless.

Cutting it down, pulling it out and digging it up are the best ways to begin the attack on winter creeper. Where digging doesn’t work, try cutting it back and applying glyphosate herbicide (such as Roundup) as a 2-percent solution (8 ounces per 3-gallon mix) in water to the stump that’s left. You’ll have to keep doing this, and you’ll have to be careful not to get the herbicide on the surrounding plants.

After the vine has been removed, the best way to keep it from returning is to keep an eye on the area and pull up individual seedlings as soon as you see them.

Small space, big harvests

Is that really possible? Maybe, and there’s a new book in the Complete Idiot’s Guide series that’s here to help. The book is The Complete Idiot’s Guide to Small-Space Gardening, and the author, Chris McLaughlin, provides quite a bit of good information on how to make the most of whatever plots or pots you have available. It’s published by Alpha Books; the price printed on the book is $19.95; at the Web site idiotsguides.com it’s listed as now $12.97.

Cover the ground, not the daffodils

QUESTION: What groundcovers can be used that will allow daffodils to come up in the spring?

Spring bulbs will grow through English ivy, but there are better groundcover choices to use.

Several plants used as groundcover permit spring-flower bulbs to grow through. Nashville-area garden specialists offer a few recommendations:

Ajuga, or bugleweed (Ajuga reptans). To some people this is a nice groundcover, to others it’s a weedy nuisance. It can be aggressive, but in the right spot it might be just what you need.

Periwinkle (Vinca minor), grows in shade, is green all year, and has pretty blue or white flowers in spring. Please note: Vinca minor is listed among the invasive exotic plants in Tennessee. Please use responsibly.

Daffodils will also push up through English ivy (Hedera helix), but because it, too, is an invasive exotic that can climb trees and displace more desired species, I would never suggest planting it in the landscape.

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Sweet surprise: sweet potato vines

QUESTION: The ornamental sweet potato vines I grew in large pots last summer produced potatoes – to my surprise! Can they be replanted to produce vines next year?

Sweet potato vine (Ipomoea batatas) ‘Blackie’

Yes! The sweet potatoes that are grown for their ornamental vines don’t have much taste, but U.T. Extension agent David Cook says you can save the tubers to produce the same foliage next year. Here’s how to do it:

If the potatoes haven’t already frozen (and by now, you may find that they have, unfortunately), dig them up and store them packed in straw in a dry, cool place. When the weather begins to get warm again, the tubers may begin to sprout. Cut them into sections just as you would cut a seed potato, with at last one “eye” per section. Allow them to dry for a few days, and plant them in the ground after the frost date has passed (mid-April here in Middle Tennessee).

Ornamental sweet potato vines come in a variety of fancy-leafed “flavors.” ‘Blackie’ is an easy-to-find favorite, with purplish-black, deeply lobed leaves. ‘Ace of spades’ has heart-shaped leaves. ‘Tri-color’ is variegated with green, white and pink foliage, and the variety called ‘Marguerite’ has golden-green leaves.

The vines grow fast, and are a striking addition as a “spiller” in a container, draping elegantly over the sides. I learned last summer that rabbits find the leaves tasty. If your garden has a resident rabbit (as mine does), you’ll find the vines will start to disappear, so be warned.

Clearing up clematis confusion

QUESTION: I am looking for a white, late-blooming clematis. What can you tell me about it? – Franny

Sweet autumn clematis.

You are probably describing the late-summer-blooming vine that is either sweet autumn clematis or the vine commonly called virgin’s bower. They are both deciduous vines, look similar, and bloom about the same time, but there’s a difference.

Clematis terniflora, the sweet autumn clematis, is a vine that is native to Japan. Here’s what the Southern Living Garden Book says about it: “Tall and vigorous (some would say rampant)…Self-sows readily; can become a pest.” They admit it makes a good privacy screen with its “billowy masses of 1-inch wide, fragrant, creamy white flowers in late summer, fall.”

Digging deeper, I found it listed as a “lesser threat” (as opposed to a “severe” or “significant threat”) by the Tennessee Exotic Pest Plant Council, which lists invasive plants. Not long ago, a friend who has it in her garden told me it is covering up other shrubs in the garden, and she will have to pull it up. Consider yourself warned.

© 2002 Steve Baskauf http://bioimages.vanderbilt.edu

Virgin's bower

The vine called virgin’s bower is C. virginiana, and it’s native to the eastern U.S. It’s described as having “bright green foliage; profuse show of sweetly fragrant, 1¼ inch white blossoms in 3 to 6-inch long clusters in late summer, fall.” It also goes by the common name “devil’s darning needles.” It may also self-seed and could get out of hand if you don’t pay attention, but at least it’s not labeled an invasive pest.

The sweet autumn clematis is likely the most readily available in nurseries and garden centers; to find virgin’s bower, you may have to look for nurseries that specialize in native species. Here are three in theNashville area:

Growild, a wholesale nursery in Fairview that welcomes retail customers by appointment (http://www.growildinc.com/); Nashville Natives, which provides plants for sale at Whole Foods and Gardens of Babylon (http://www.nashvillenatives.com/); and Moore & Moore Garden Center, a retail nursery at 8216 Highway 100 (http://www.mooreandmoore.com/)

Banishing ‘leaflets three’

QUESTION: What’s the best way to get rid of poison ivy?

Growing up where pavement and neatly trimmed lawn were the modern idea of landscaping, I didn’t encounter poison ivy until I became a real gardener. But by the time  I did learn the mantra (Leaflets three – let it be!) I knew to keep well away from it. Unfortunately, it seems to show up everywhere these days.

The best way to deal with poison ivy is, of course, to treat it very carefully. Fitzroy Bullock, a professor at Tennessee State University’s Cooperative Extension Program, has written a fact sheet on identifying the vine and dealing with it in the landscape.

When you find the sweet little seedlings in garden beds (often at the edges of the lawn, along fence lines, places that don’t get regular mowing), you can dig them out, roots and all, and dispose of them. Wear long sleeves and gloves to do the job. If you use disposable gloves, you can throw them away when you’re done, and avoid the possibility of accidentally getting the plant’s irritating oil on your skin. Some have suggested using a plastic newspaper bag as a glove, of sorts. Put your hand in the bag, use it to pull the vine out of the ground, then peel the bag off, inside out, with the vine inside.

If it’s a big vine with a well-established root system, it’s a bit harder to get rid of. Cut it as close to the ground as possible, and to keep it from growing back, immediately treat the stem with a garden herbicide that contains glyphosate (such as Roundup). Don’t spray the vine itself, and be careful not to let the spray get onto other plants, because glyphosate – or even a drift from the poison – will kill or damage most every green thing it touches.

Even after it’s dead, a large vine can be a problem. The toxic leaves dry up and fall on the ground, and later, after the aerial roots that have held it up begin to die, the whole vine could fall. Dispose of dead leaves and vines carefully, because the toxin is still present.

You may need to apply a second helping of herbicide if the vine begins to grow again from the stump. Apply herbicide again when the new, young leaves have opened fully.

If you are sensitive to the plant and accidentally make contact, expect intense itching, rash and blisters – not a serious situation, but certainly bothersome for a few days. It’s a good idea at any rate to wash your skin with soap and water after a day in the garden.