Extension Master GardenerSM Volunteers of Buncombe County

weeds

Weeds Overwhelming? How to Cope!

Warm, wet weather equals a wealth of weeds. Despite many of us being home more of the time this summer, we can’t seem to keep up with the weeds! Fortunately, there are weed scientists who can help!

 

 

Weeds compete with your vegetable garden crops


Why care about weeds?
Maybe you are hoping to just peacefully coexist with your weeds, but according to Kira Sims, a Ph. D. candidate and graduate teaching and research assistant in the North Carolina State University Horticultural Science program, weeds:

  • Compete for resources—such, as nutrients, space and sunlight—with more desirable plants.
  • Can reduce crop yields.
  • Adversely affect human health—some weeds such as ragweed and poison ivy can cause allergic reactions.
  • Alter ecosystems—weeds can crowd out native plants or even make soil less hospitable to natives through altering pH, for example.

What can you do about weeds? IWM!
Integrated Weed Management is “Science-based, socially acceptable, environmentally responsible and economically practical crop protection against pests” says Sims, using all of the tools in your toolbox!

What’s in the toolbox?
Sims advocates the PAMS approach:

  • Prevention tools include:
    • Using clean (weed-free) compost, mulch, seeds, topsoil, transplants.
    • Don’t let weeds reproduce—by setting seed, suckering and so on.
    • Water desirable plants not weeds.
    • Clean equipment that might transport weeds
    • Remember you and your pets can transport weed seeds!
  • Avoidance tools include:
    • Clearly define where you want to exclude weeds
    • Help your desirable plants outcompete the weeds by:
    • Choosing appropriate plants
    • Plant at the correct time
    • Fertilize appropriately
    • Rotate crops
  • Monitoring tools:
    • Scout for weeds regularly
    • Keep records of crops and the weeds that cause problems
    • Test soil to determine appropriate fertilization
  • Suppression tools for when you can’t prevent or avoid all weeds:
    • Reduce tilling—which brings up weed seeds
    • Use narrow row spacing to shade out weeds
    • Use cover crops and/or mulch over bare soil
    • Manage irrigation

                                    

                                          Article by Buncombe County Extension Master GardenerSM Volunteers

For more information:

Weed publications from NCSU, including specific links on managing crabgrass, Japanese stiltgrass, and ragweed:

https://content.ces.ncsu.edu/catalog/?keywords=weed-management

 

 

 

 

 

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:

 

Vegetables: The Carrot Family (Apiaceae)—Roots and Herbs

Did you know that carrots are related to celery, celery root (celeriac), fennel, parsnips, and lots of herbs used for their foliage and/or seeds, including angelica, anise, caraway, coriander, cumin, chervil, cilantro, dill, lovage, and parsley? We also call plants in the Apiaceae family umbellifers because of their umbel-shaped blooms, which are like umbrellas. You can grow most of these plants in your own garden—some you can start right now for fall harvest!

Heirloom carrots

Grow carrots in clay?
Yes, you can! Many WNC gardeners don’t bother with carrots (Daucus carota var. sativus) because they are so readily available in stores and they think they won’t do well in our clay soils. Home-grown carrots come in many shapes, sizes, and even colors, making them a tasty addition to your garden. Raised beds and container gardens are one way to avoid heavy soils, but choosing smaller varieties, such as ‘Thumbelina’ or ‘Paris Market’ or Nantes varieties, which are shorter and have blunt tips are better choices if your garden is “clayey.” 

Planting
You can still plant carrots, dill, parsley, and parsnips (Pastinaca sativa) now through mid-August for a fall crop. You can even leave your carrots and parsnips in the ground and harvest them as needed as long as temperatures stay above about 20F.

Although you can often find parsley and other herbs as transplants, plan to grow Apiaceae from seed. Plant directly in the ground in a sunny spot. Although best in full sun, many will tolerate partial shade if you’re short on space.

Annual, biennial, or perennial?
Although we grow most Apiaceae as annuals, many are biennials or even perennials. Annuals complete their life cycle in one season, while biennials form roots and leaves their first year, then flower and seed before dying in their second year. Perennials typically live for more than two years.

Knowing the lifespan of the plants you are growing is important because you may need to leave them in in the ground beyond one season to harvest your desired crop; also, if you are buying transplants, beware! One spring I got a great deal on large parsley plants, only to have them immediately start to go to seed, showing their biennial nature.

  • Anise, chervil, cilantro/coriander (yes, they are the same plant—the leaves are known as cilantro and the seeds are coriander), cumin, and dill are annuals.
  • Angelica, caraway, carrots, celery, celeriac, parsley, and parsnips are biennials.
  • Fennel and lovage are perennials.

Maintenance
Water. Keep your planting moist until seeds sprout. Water regularly throughout the growing season.

Thin/Weed. Knowing your crop seedlings from weeds is always important! Many Apiaceae have ferny foliage, which may help. Thinning is important for root crops, so leave at least an inch or two between carrots and parsnips. Weed often as pulling large weeds may damage your crop roots; cutting off weeds at the soil surface may help. Weeding after a rain and watering after weeding help avoid root damage.

Fertilize. Apiaceae are not heavy feeders, but you want to see healthy foliage to produce roots and provide leaves and seeds in your herb crops, so some fertilizing during the season may be helpful.

Insects and diseases to watch for. Armyworms, carrot worms, and leafhoppers may feed on your plants. Leafhoppers also spread aster yellows, which affect carrots and celery. Swallowtail butterfly larvae feed on dill, fennel, and parsley. 

Beware toxic and invasive Apiaceae

There are some very toxic members of the Apiaceae family! Be careful around the leaves of garden parsnips, which can cause an allergic rash in some—and never eat parsnip leaves or stems. You may have heard about the giant hogweed (Heracleum mantegazzianum), which can cause blistering and burning skin reactions—much worse than poison ivy—and even blindness. We recently identified poison hemlock (Conium maculatum) growing at our Extension office. This is another plant you don’t want in your landscape because eating any portion of the plant can be fatal! Even the wild carrot (Daucus carota) known as Queen Anne’s lace is considered a problematic invasive plant throughout the southeastern United States. Remove it before it goes to seed if you have it in your landscape, but be sure of your identification—use extreme caution when handling unknown Apiaceae plants.

Article written by Debbie Green, Extension Master GardenerSM Volunteer.

More information:
Garden Planting Calendar for Annual Vegetables, Fruits, and Herbs in North Carolina
by NCSU Cooperative Extension

Vegetable and Herb Seedling Photographs
by Travis Saling, The Westside Gardener

Invasive, Exotic Plants of the Southeast: Queen Anne’s Lace
by NC State University

Giant Hogweed? Maybe It’s Cow Parsnip, Poison Hemlock, or Purple Angelica
by University of Illinois Extension

Pest Alert: Giant Hogweed
by North Carolina Department of Agriculture and Consumer Services (NCDA & CS)

Contact Us

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

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