Extension Master GardenerSM Volunteers of Buncombe County

IPM

Acronym for Integrated Pest Management: A strategy for keeping plant damage within bounds by carefully monitoring crops, predicting trouble before it happens and then selecting the appropriate controls — biological, cultural, or chemical as necessary.

Teaching Moments in the Garden

Fickle Days of Winter
A teaching moment in my garden was learning about Western North Carolina’s interesting and sometimes challenging transition to spring. My first gardening year in WNC provided several days of 75-to-80-degree weather in February. Since my new neighborhood was fully bursting into bloom and I was eager to get into the garden, I happily started my early spring gardening activities. Much to my chagrin, I soon learned about the multiple stages of winter in WNC, including Blackberry Winter. I now know that it’s best to wait until Mother’s Day to install tender plants here. My lesson:  Be wise. Be safe. Pause and do a little research before jumping into any new gardening activity.
By Catherine Pawlik, Extension Master GardenerSM Volunteer

Editor’s Note:  For more information about Blackberry Winter, see:
https://www.buncombemastergardener.org/?s=blackberry+winter
For an interactive map of average first and last frost dates in NC, see:
https://gardening.ces.ncsu.edu/average-first-and-last-frost-dates/

Red twig dogwood in winter

Supporting Nature’s Food Web
A teaching moment in my garden occurred when I witnessed some birds feeding on sawfly larvae which were feeding on my red twig dogwood. I had been hand-picking the pests for years, not realizing that they were natural food for the birds visiting my yard. I have since discovered that sawfly larvae are also food for lizards, frogs, ants, predatory wasps, and other beneficial insects. While other gardeners may not tolerate a defoliated red twig dogwood in late summer, I’ve decided to accept it.

There are many different species of sawflies—pine, dogwood, elm, rose, hibiscus, and others. Species are host-plant specific, meaning the dogwood sawfly isn’t going to migrate among host plants to attack pines. Although no one wants their prized thunderhead pine stripped of all its needles, a gardener may decide to ignore sawfly on an otherwise healthy red twig dogwood. Most plants will survive an onslaught of sawflies unless the infestation becomes very severe.

Dogwood sawfly larvae in next to last development stage_Whitney Cranshaw_CO State Univ
Dogwood sawfly larvae

Watching the birds devouring sawfly larvae taught me a lesson:  Pay close attention to how my garden supports a complex food web. Plants provide food and habitats for all kinds of animals—insects, spiders, butterflies, beetles, birds, squirrels—which in turn become part of nature’s food chain. Today, before I charge into the garden to do battle with pests, I take time to correctly define the problem and my action plan. What is the insect and is it harmful or beneficial? What is the plant’s susceptibility to damage? Is treatment needed? If so, what kind, when, and how? Gardeners call this Integrated Pest Management or IPM.

I’ve learned that removing one food source or habitat may disrupt the natural system, where even an insect pest contributes to the food chain. For now, I’ll continue to love my red twig dogwood both for bird food and its beautiful red stems in winter.
By Judy Lemanski, Extension Master GardenerSM Volunteer

Editor’s Note:  For more information on identifying and controlling sawflies, see:
https://content.ces.ncsu.edu/search_results?q=sawflies&collection=
https://content.ces.ncsu.edu/dogwood-sawfly
https://hort.extension.wisc.edu/articles/sawflies/
For information about Integrated Pest Management, see:
https://content.ces.ncsu.edu/extension-gardener-handbook/8-integrated-pest-management-ipm 

Preying Mantis_Ken Venron_CC BY 2.0_Flickr
Praying Mantis

Future Gardener Discovers a ‘Stick’
One morning I was sipping coffee on the patio and watching my three-year-old granddaughter pluck leaves off a nearby bush.  “Gramma, Gramma.  Come here quick,” she cried.  “Look at the stick.  Look at the stick.”  I couldn’t figure out what she was talking about.  Then I saw it!  A praying mantis, perched on a stem of the shrub and looking just like a stick!  Maddie watched with amazement as it rubbed a front leg across its face, cocked its head, and then slowly crawled away!  And I captured the teaching moment to tell my granddaughter (who hated bugs) all about the importance of good bugs in the garden.  It was “just a stick,” but it led my little future gardener on scavenger hunts, searching for more bugs and making up stories about their lives in the garden.
Beth Leonard, Extension Master GardenerSM Volunteer 

Non-Native Invasive Plants: Bamboo—The Plant We All Love to Hate!

A visitor to the Extension Master Gardener office told me he had a plant to identify that was too big to bring inside—that got my interest. In the back of his truck he had a grass-like plant over 10 feet tall with hollow stems!

 Bamboo or river cane?

I was looking at either a running type of bamboo (Phyllostachys spp.) or another form of bamboo: river cane (Arundinaria spp.). The difference between the two? One is an extremely aggressive invasive native and the other is a native.

 Phyllostachys aurea is a bamboo species of the ‘running bamboo’ type. It is commonly known by the names fishpole bamboo and golden bamboo.  This is the species most widely seen in the landscape. A related species is Phyllostachys nigra—black bamboo—is also widely cultivated and invasive! They both form dense—almost impenetrable—thickets that crowd out all other plants.

Invasive Bamboo

Arundinaria is the only bamboo native to North America, found in the south-central and southeastern United States. It is tree-like, growing to heights up to 26 ft. It has distinctive fan-like cluster of leaves at the top of new stems called a top knot. Arundinaria gigantea, commonly known as river cane, is a woody plant native to North Carolina.  River cane communities occur on floodplains, bogs, along streams and rivers and in riparian woods.

River Cane

It became obvious to me that my visitor just wanted it gone from his yard!

Dr. Joseph C. Neal, Department of Horticultural Science, at NC State University, discusses three techniques for dealing with bamboo in the publication “Controlling Bamboo in Landscape Plantings.”

Removal

To eliminate a planting completely requires physically removing as much of the top growth and root mass as possible—this will require power equipment for large infestations! Bamboo will regenerate from any small rhizomes left behind so long-term follow-up will typically require the use of herbicides or planting the area in lawn:

  • Chemical control involves spraying with a post-emergent, non-selective herbicide such as glyphosate and may require repeated spraying whenever new growth occurs.
  • Convert to lawn avoids the use of herbicides and relies on the fact that bamboo will not tolerate frequent mowing. This works only if you mow the entire area! If you don’t eliminate the entire stand, new shoots will keep moving in from the remaining plants.

Containment

  • If you want to contain a bamboo planting, you can install a barrier— concrete, metal, plastic, or pressure-treated wood—installed at least 18 inches deep that slants outward and rises at least a couple of inches above the ground. Because barriers only deflect rhizomes rather than prevents them from growing, you will need to inspect the barrier at least yearly to remove any new rhizomes.

Regardless of which method of control you choose, eradicating a bamboo infestation requires intensive effort over several years.  Of course, the best way to prevent bamboo from becoming a weed is to avoid planting the invasive, spreading-type bamboos in the first place—and ask your neighbors to avoid it, too!

 Article by Bob Wardwell, Extension Master GardenerSM Volunteer

Controlling bamboo in landscape plantings:

https://content.ces.ncsu.edu/controlling-bamboo-in-landscape-plantings

Identifying Native Bamboo: www.namethatplant.net/article_nativebamboo.shtml

More about river cane:

http://www.indefenseofplants.com/blog/2017/6/26/north-americas-native-bamboos

Non-Native Invasive Plants: Oriental Bittersweet (Celastrus orbiculatus)

If you knew how awful it is, you would have nothing to do with oriental bittersweet! It is an aggressive, woody, deciduous, perennial vine capable of girdling stems and trunks of shrubs and trees, damaging their bark and underlying tissue. Despite its weedy behavior, oriental bittersweet is still sold and planted as an ornamental vine and should be avoided.

Oriental bittersweet vine chokes tree_photo by G. Merrill
Oriental bittersweet vine

Identification:

  • Leaves: Finely toothed, round glossy leaves are arranged alternately on the vine. They range from 2 to 5 inches long and 1.5 to 2 inches wide.

    Oriental bittersweet (Celastrus orbiculatus)_Leonara Ellie Enking_CC BY-SA 2.0_Flickr
    Oriental bittersweet foliage
  • Flowers: Clusters of 2 to 7 blossoms where the leaf attaches to the stem (leaf axil). Each flower has 5 petals and 5 sepals.
  • Fruit: Green-to-yellow round fruits ripen in the fall. Upon ripening, the fruits split open revealing three red-orange, fleshy berries that remain on the vine through the winter. The many birds and small mammals that feed on the berries distribute seed far and wide. A single plant can produce almost 400 fruits!

    Oriental Bittersweet_berries_Katja Schulz_CC BY 2.0_Flickr
    Oriental bittersweet Fruit
  • Distribution: Oriental bittersweet’s distribution ranges from central Maine south to North Carolina and west to Illinois;
  • Ecology: It can grow in woodlands, fields, hedgerows, coastal areas, and salt marsh edges. It tolerates shade but prefers full sun.

Management Options:

  • Mechanical control: Pull light infestations by hand—before fruiting, if possible. If fruits are present, bag the vines to make sure the seeds do not contaminate the site. Cutting the vines at the base early in the season will prevent flowering and fruiting, but you must remove all of the roots so the bittersweet will not re-sprout. Frequent mowing will also exclude oriental bittersweet, but infrequent mowing—two to three times a year—can stimulate root suckering.
  • Chemical control: You can successfully manage heavy infestations of non-native bittersweet with herbicides containing the active ingredient Triclopyr. The chemical is most effective applied immediately to the cut stem surface of cut or mowed vines. Apply herbicides prior to the emergence of native plants or after the last killing frost to help avoid herbicide contact with desirable plants. As with any herbicide, carefully follow the label guidelines when handling and applying.

American bittersweet (Celastrus scandens) is native to the eastern United States and is easily confused with oriental bittersweet. Leaf shape is highly variable and not a good characteristic for identifying American vs. Oriental bittersweet. Watch for flowers and fruits to distinguish the two:

  • American bittersweet flowers and fruits are only found at the ends of stems, Oriental bittersweet flowers and fruits are found all along the stem at leaf axils.
  • American bittersweet has orange capsules around red fruits, Oriental bittersweet has yellow capsules around red fruits.

A HOLIDAY CAUTION: Do NOT use oriental bittersweet in outdoor decorations! If you have any decorations containing oriental bittersweet fruits, be sure to bag them and discard—Do not compost!

Article by Bob Wardwell, Extension Master GardenerSM Volunteer

For More Information:

 

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Buncombe County Extension Office
49 Mount Carmel Road
Asheville, NC 28806
Helpline 828-255-5522

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