Extension Master GardenerSM Volunteers of Buncombe County

Weeds

Goldenrod in the Garden: Dispelling the Allergy Myth

If late summer and autumn allergies—known as “hay fever”—affect you, you are not alone! Millions of Americans suffer from seasonal runny nose and itchy, watery eyes. Much of this allergic reaction is blamed on goldenrod and ragweed, when, in fact, only ragweed spreads irritating pollen—goldenrod does not! Goldenrods (Solidago spp.) and ragweed (Ambrosia spp.) mature in late summer; but the showier goldenrod is insect-pollinated, not wind-pollinated and that’s what makes the difference.

Goldenrod meadow_by BLeonard_BCEMGV
Fall meadow dressed in goldenrod

Ragweeds are the villains!
Ragweeds are annual native weeds found in cultivated areas, as well as along roadsides and meadows in heavy soils. In early spring, common ragweed’s (A. artemisiifolia) first leaves are opposite but become more deeply dissected and arranged alternately as the plant matures. It can grow to 4 feet tall. It produces only inconspicuous flowers of nondescript color, but in early autumn, breezes distribute clouds of allergy-causing pollen as we seek to enjoy the late summer and early autumn. If you learn to recognize its leaves, it is easy pull any time before it flowers, and mowing will keep it under control—you will be shearing off any flower stalks before they bloom. Note that we also have giant ragweed (A. trifida) in our area that also produces irritating pollen. It is much taller—up to 16 feet!—and has opposite leaves with 3 to 5 large lobes and flowers much like common ragweed.

Welcome goldenrod to your garden!
Goldenrod is a native herbaceous perennial in the aster or Asteraceae family that presents dazzling displays of brilliant yellow flowers in open meadows and roadsides. These bright yellow flowers hold sticky pollen that attract bees, butterflies, and other insects until early frost. As the floral display matures, birds flock onto upright stems to enjoy the seeds.

Although sometimes viewed as weeds, these wildflowers represent a very diverse collection of many species:

  • They range in size from little more than 12 inches to 6 feet tall.
  • Some spread aggressively, while others form well-behaved clumps.
  • In addition to soft plumes, goldenrods’ yellow flowers can be spiky or even zig-zagged!
  • There are species adapted to many habitats, from salt marshes, to swamps, prairies and woodlands.
Goldenrod (Solidago)_Leonora (Ellie) Enking_CC BY-SA 2.0_Flickr
Goldenrod in the garden

Those found in our mountains are a welcome addition to perennial gardens, combining well with Echinacea, ironweeds (Vernonia spp.), Joe Pye weeds (Eutrochium spp.), Rudbeckias, taller sedums, and ornamental grasses to add vivid color to the late summer garden. They are also lovely additions to floral arrangements. Some local natives include:

  • Early goldenrod (Solidago juncea) starts blooming in July and is drought-tolerant.
  • Sweet goldenrod (Solidago odora) has anise-scented shiny leaves, reaches only about 2 to 3 feet tall and has a well-behaved clumping habit.
  • Common goldenrod (Solidago altissima altissima also known as Solidago canadensis var. scabra) is a tall (up to 6 feet) plant that spreads aggressively by underground rhizomes, which can be an advantage in controlling erosion, even on steep slopes.

Goldenrods are subject to very few diseases, and although you may see some galls, spider mites and lace bugs, deer typically ignore them.

So, as September arrives, bringing the first falling leaves, hints of coolness in the air, and breezes carrying pollen, don’t be concerned about goldenrod. It’s a harmless beauty!

What to do about allergies?
Donna Teasley, Extension Agent, recommends ways allergy sufferers can keep symptoms to a minimum:

  • Avoid hanging laundry to dry outside.
  • Hire someone to mow the lawn during late summer.
  • Keep bedroom windows closed at night.
  • Keep car windows rolled up while driving.
  • Stay indoors on windy days and at peak pollen hours—early morning and late afternoon.

While these suggestions can certainly help allergy sufferers cope, one final thing we can do to lift our spirits as we gaze outdoors or ride along is to take time to enjoy the goldenrods!

Article written by Mary Alice Ramsey, Extension Master GardenerSM Volunteer.

More information
Read about different types of goldenrod, from the wildflower to cultivars for the garden.
NC State Extension publications

Common Ragweed
by Charles Peacock, Professor and Extension Turfgrass Specialist
NC State Extension

Giant Ragweed
by Dr. John Hilty, Illinois Wildflowers

Allergy Sufferers Alert
by Donna Teasley, Extension Agent, Burke County, NC
NC Cooperative Extension

Controlling the Weedy Creepers: It’s Not for the Faint of Heart!

Creeping Charlie, Indian mock strawberry, smilax—these innocent-sounding names describe creeping broadleaf weeds that can quickly cause problems in your landscape! These ubiquitous plants, once established, are difficult to eradicate. So, what’s a gardener to do?

Ground Ivy_Derek Hudgins_CC BY-SA 2.0_Flickr
Ground ivy or creeping Charlie

Creeping Charlie or ground ivy (Glechoma hederacea)
This mint family (Lamiaceae) member is a vigorous invasive weed European settlers brought for food and medicinal purposes. Today we consider it an uninvited guest!

Identifying characteristics: The opposite leaves are scalloped, roundish, or kidney-shaped, and heart-shaped at the base of the square stems. In the spring, creeping Charlie produces blue-violet funnel-shaped flowers in whorls at its leaf axils. It “creeps” by vining stems that take root at leaf nodes. Be careful not to confuse it with the similar-looking button weed or common mallow (Malva neglecta), which has round stems and alternate leaves; or the annual henbit (Lamium amplexicaule), a winter-blooming plant with pink flowers that may sprawl but does not root at the stem nodes.

Growing conditions: Creeping Charlie prefers moist soil and shade, but also grows in the sun. Its presence may indicate too much shade, too much moisture, and/or poor fertility.

Control: Improve surface drainage, aeration, and water less frequently. In a lawn, healthy turf can be your first line of defense. In gardens and open areas, mulch is your best deterrent. When discovered early, hand-weeding is a good option, but do not put creeping Charlie in the compost pile! As a last resort, treat out-of-control infestations with a broad-leaf weed killer in the fall; treat in spring only when the plants are in bloom. Check with the Extension service for recommended chemicals.

Indian mock strawberry_Dinesh Valke_CC BY-SA 2.0_Flickr
Indian mock strawberry

Indian mock strawberry (Duchesnea indica)
Introduced to the United States as a decorative plant with medicinal properties, this Asian native resembles “real” strawberry plants.

Identifying characteristics: Indian mock strawberry spreads using hairy stolons or runners and reproduces by seed. Its blossoms are yellow; true strawberry flowers are white or pink. In addition, mock strawberry leaves have rounded “teeth”; the teeth on cultivated or wild strawberry leaves are pointed.

Growing conditions: Indian mock strawberries like moist conditions, are shade tolerant, and close mowing is not a deterrent.

Control: As with creeping Charlie, healthy turf and mulch are two of the best ways to control and prevent infestations. Hand-pulling will take care of the problem if the infestation is small or plants are young.

Greenbrier or Smilax_Kerry Wixted_CC BY-NC 2.0_Flickr
Greenbrier, catbrier, or smilax

Greenbrier or catbrier (Smilax spp.)
These are native plants in the Liliacae family (which also includes daylilies, lilies, and yuccas). Most are woody vines, some deciduous, others are evergreen; many have thorny stems. Some are ornamental, while others are just plain weedy, but all are valuable wildlife plants providing food and cover for many species of birds and mammals.

Identifying characteristics. Smilax have well-developed underground rhizomes or tubers and most species climb using tendrils. The most common species in WNC have ovate or lance-shaped alternate green leaves; stems are round and frequently prickly. Female plants have small greenish-yellow flowers in the spring and early summer that produce blue-black berries in the fall.

Growing conditions: Smilax isn’t particularly picky. You’ll find it along roadsides, clearings, and woods where there is partial or even deep shade. Birds eating the berries facilitate seed dispersal.

Control: The plants’ extensive rhizomes make them very difficult to control. Dig plants removing as much of the root system as possible. Although the vines quickly regenerate when cut back, you can keep them from overwhelming other plants by frequent trimming. Also, smilax leaves are a favorite white-tailed deer food, so having these vines in your landscape might help spare your hostas or other ornamental plants! 

Article written by Janet Moore, Extension Master GardenerSM Volunteer. 

Read more:
TurfFiles: Ground Ivy Description
TurfFiles: Indian Mock Strawberry Description
Greenbrier (Smilax spp.)

A Dilemma: “Weed” or Pollinators’ Best Friend?

No, this poster is not an advertisement to plant more thistles! As part of a class on the need for pollinator habitat, it provoked questions and the rethinking of some old ideas.

Thistle_weed or pollinator forage
Thistle

A patch of any kind of flowers covered with bees and butterflies is a bit like a soda fountain or candy counter jammed with kids. Pollinators choose flowers that are close by, abundant, and shaped so their tongues can reach the rich reward inside—nectar! Flowering weeds—what we gardeners sometimes define as a “plant out of place”—fit all these requirements. And so, pollinators discovered the virtues of flowering weeds millennia ago.

Maybe it’s time to take a new look at your lawn and garden weeds, through the lens of these creatures who are responsible for so many of the fruits, vegetables, nuts, seeds, and oils we eat. Maybe you, too, will discover the virtues of weeds already valued by our pollinators.

What pollinators need
All 4000 native bee species, as well as imported honey bees, depend on flowers for food! They get carbohydrates from the sugary nectars and proteins and fats from flower pollen. Moths and butterflies also require the foliage of specific host plants, in addition to their flowers, to provide food for their hatched butterfly and moth eggs. 

Flowering spring “weeds”
With the arrival of spring, early-emerging solitary bees, such as the mason bees, go to work pollinating berries and tree fruits. Mated bumble bee queens are coming out of hibernation to begin nest construction and egg laying. Perennial honey bee colonies build up their populations from the 10,000-strong winter clusters to mighty summer-foraging forces of 50,000 or more!

Many winter- and early spring-flowering weeds provide these pollinators much-needed food when little else is in bloom. Purple deadnettle (Lamium purpureum), henbit (Lamium amplexicaule), and dandelion (Taraxacum officinale), for example, are important nectar and pollen sources.

Flowering fall “weeds”
Fall is an equally busy feeding time for our pollinators. Wasps and hornets seem to know that their nests will soon be empty. Bumble bees are rearing queens. Honey bees are filling hives with honey they will need to survive the winter. They’re also rearing important winter bees with special fat body glands that are repositories of nutrition for babies that will hatch after the winter solstice.

Fall-blooming asters (Symphotrichum spp.), goldenrods (Solidago spp.), Joe Pye weed (Eutrochium ssp.), and ironweed (Vernonia, spp.)—all native plants that are often treated as weeds—provide significant staples at a time of frantic pollinator feeding when other blooming plants are in short supply.

Honey bees on butterfly weed
Honey bees on butterfly weed

A special note on butterfly weed vs. butterfly bush
Ironically, the plants with “weed” in their common names, milkweed and butterfly weed (Asclepias spp. and A. tuberosa), are the essential host plants required for Monarch butterfly reproduction. But, the foliage of butterfly bush (Buddleia spp.) is of no value to any moth or butterfly in the United States. Yes, butterfly bush flowers provide nectar, but the plants escape our landscapes and show up unbidden in the wild as plants out of place!

Is your landscape a food desert to pollinators?
Or does it include a smorgasbord of useful, attractive flowering plants? Adding native flowering annuals, perennials, vines, shrubs, and trees to your yard will provide foliage for butterfly and moth larvae, as well as flowers for all pollinators. In your lawn, white clover (Trifolium repens) blooms provide nectar in summer (and as a bonus, clover along with your grass clippings may put enough nitrogen back into the soil to fertilize your lawn). Richard Orlando, in Weeds in the Urban Landscape: Where They Come From, Why They’re Here, and How to Live with Them, notes that other low-growing flowering plants, such as thymes (Thymus spp.) and self-heal (Prunella vulgaris), are lovely and useful additions to a grass lawn.

Ironweed at garden edge_Eleanor_CC BY-NC 2.0
Ironweed at garden edge

You decide!
No one can—or should—tell you which plants are weeds and which are not. Of the uninvited guest plants in your yard, you decide: stay or go? Plants such as the early spring weeds can stay but not be allowed go to seed. Some may get to grow at the edge of the lawn. Some may be treasured native plants.

Options, decisions, and responsibilities abound. Just remember to use your pollinator lens from time to time when you head out to the garden to weed. Remember what A. A. Milne, the creator of Winnie the Pooh, says: “Weeds are flowers, too, once you get to know them.”

Article written by Diane Almond, Extension Master GardenerSM Volunteer.           

For more information
Gardening for Pollinator Super Heroes!
by NC Cooperative Extension

Orlando, Richard. Weeds in the Urban Landscape: Where They Come From, Why They’re Here, and How to Live with Them. Berkeley: North Atlantic Books, 2018.
(Although the plant list is specific to California, the history, discussion on IPM, and notes on many plants are appropriate for WNC.)

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

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