Extension Master GardenerSM Volunteers of Buncombe County

Weeds

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.)

The Grass Isn’t Always Greener—Sometimes It’s a Weed!

“A weed is a plant that has mastered every survival skill except for learning how to grow in rows.” Wisconsin humor columnist Doug Larson

He’s right! Grassy weeds are the masters of survival, thriving in adverse conditions and dramatically outpacing the plants we want to succeed.

Grassy weeds_Goosegrass_Eleusine indica_inflorescence_NY State IPM at Cornell_CC BY 2.0_Flickr
Grassy weed ready to spread seeds

Here come the grassy weeds
Grassy weed seeds hide in root balls and find their way into seed packets. Wind, rain, birds, and even household pets spread the seeds across our lawns and gardens. Once rooted, grassy weeds can quickly take over, spreading their roots, stolons, and tubers. What’s a gardener to do?

Begin with identification
Grassy weeds come in all sizes and shapes. They can be annual, biennial, or perennial. And some, like sedges and rushes, aren’t really grasses at all, but are easily mistaken for grassy weeds at first glance.

Leaves and stems are the easiest way to distinguish grasses and sedges from other broadleaf weeds. Broadleaf weed leaves are usually wide and come in a variety of shapes, including round, oval, or lanceolate. Their stems are either square or round. These weeds usually have identifiable flowers—think dandelions! Grasses and sedges, on the other hand, have long, narrow leaves that generally grow upright, often in clumps. Grass stems are round or flat, while sedges have triangular-shaped stems. Try rolling a sedge stem between your fingers—you can easily feel the bumpy edges. Instead of producing typical flowers, grasses and sedges send out spikes of tiny, individual florets and scale-like bracts, respectively .

Rushes come in many varieties—some that grow in clumps with soft, grass-like foliage (soft or common rush, Juncus effusus); others that grow on hollow, stiff stems (horsetail or scouring rush, Equisetum hyemale). Although not technically considered a “weed,” we identify them here because their emerging foliage appears grass-like. Rushes are often desirable ornamental plants in a wetland or water garden, although they may aggressively spread. 

Stubborn annual grassy weeds

  • Crabgrass (Digitaria). The North Carolina Extension Gardener Handbook tells us that crabgrass was one of the first grains cultivated in Europe during the Stone Age—little consolation when it’s taking over your lawn! Crabgrass germinates from March through May, encouraged by alternating wet/dry conditions in the spring. It has a prostrate growth habit, and spreads not only by seeds, but also by stolons that send down roots at each node.
  • Goosegrass (Eleusine indica). This invasive weed takes hold in areas where the soil is disturbed or compacted, or where turfgrass becomes thin from mowing too low. Germination is usually two weeks behind crabgrass. Its name may have come from the belief that geese ate the grass or that various parts of the plant resemble a goose’s foot. Goosegrass has a prostrate growth habit, its foliage radiating outward from a white center like a wagon wheel. It spreads by seed and underground roots.
  • Japanese stiltgrass (Microstegium vimineum). Introduced to the United States around 1918, this annual Asian exotic invasive likely arrived in packing material for fine porcelain destined for Tennessee. Looking like a small bamboo plant, Japanese stiltgrass prospers in most Eastern states, growing in sun or shade and preferring moist habitats. Producing up to 50,000 seeds per square foot that germinate in mid- to late-spring, it forms a sprawling mass of branches 1- to 3-feet high.

Pesky perennial grassy weeds

  • Bermudagrass (Cynodon dactylon). Used as forage for hundreds of years, Bermudagrass first appeared as golf-course turf in the early 1900s. Off the putting green, stolons, rhizomes, and seeds aggressively spread Bermudagrass, making it hard to control in our tall fescue lawns or flowerbeds. Heat and drought tolerant Bermudagrass loves summer but goes dormant in winter.
  • Johnsongrass (Sorghum halepense). Mediterranean exotic introduced in South Carolina around 1830, and named for William Johnson, who planted it as a forage crop along the Alabama River in the 1840s. Many consider Johnsongrass one of the 10 worst weeds in the world (Holm, Pluncknett, Pancho, and Herberger’s The World’s Worst Weeds: Distribution and Biology). It can grow over 6-feet tall in pastures and roadsides, spreading by surface rhizomes and purple panicle seed heads.
  • Nimblewill (Muhlenbergia schreberi). A native grass easily confused with Bermudagrass. It forms a very dense mat in shaded, damp areas and in forest openings. Each spike-like panicle contains a single seed with a long bristle. 

Take quick action to control
All weedy grasses reproduce at an astonishing rate. Use Integrated Pest Management (IPM) to control the invaders and follow these tips:

  • Properly water and fertilize your landscape.
  • Mulch non-turf garden areas.
  • Hand-pull weeds when they are young.
  • Mow turfgrass to the correct height.
  • Do not let weeds go to seed.

If you use herbicides:

  • Apply pre-emergents according to the label at right time of year to prevent seed germination.
  • Spot treat with a non-selective herbicide, being careful not to let the chemical drift onto other plants or turfgrass. 

Article written by Janet Moore, Extension Master GardenerSM Volunteer. 

Learn more
Time to Maintain: Stop Crabgrass Before It Starts
Buncombe County Extension Master Gardener blog, March 2017

NCSU Turfgrass Environmental Research and Education
Describes differences in broadleaf weeds, grasses, and sedges. Provides descriptions and photos of grassy weeds. Offers checklist of characteristics to search for an unknown weed.

University of California Integrated Pest Management
Provides good list of grasses and sedges with photos & descriptions.

My Weed, Your Flower: Beware Inviting These Aggressive Spreaders into the Garden

Oxeye daisy, fleabane, evening primrose, and dame’s rocket have pretty flowers that can beguile us into inviting them into our gardens. Although birds and pollinators may appreciate them, they tend to spread rampantly, making us soon regret our invitation!

The plants
Oxeye daisies (Leucanthemum vulgare) are a perennial European species commonly found along roadsides, disturbed areas, and pastures. Oxeye daisies love moist clay soils and thrive in our region. Plants and flowers are similar to Shasta daisies grown in gardens: Leucanthemum x superbum (formerly Chrysanthemum x superbum). Oxeye daisies grow 1- to 2-feet tall and have yellow centers with white petals. They form spreading clumps through their rhizomatous roots, dispersing plentiful seeds and displacing native plants.

Annual fleabane_Melissa McMasters_CC BY 2.0_Flickr
Fleabane in flower

Fleabanes (Erigeron annuus) are native plants that are members of the aster family. They, too, are found on roadsides, fields, and disturbed areas, grow 1- to 2-feet tall and have yellow centers with white rays, although their flowers are smaller than oxeye daisies. They can be useful wildflowers in waste areas, but fleabanes have deep tap roots, making them difficult to pull. Their fluffy seed heads, like dandelions, spread these plants far and wide. Plants can serve as hosts to tomato ringspot virus.

Evening primroses (Oenothera biennis) are pretty, yellow-blooming plants, 3- to 5-feet tall, often seen on fence rows, fields, and disturbed areas. This native biennial produces leaves the first year and flowers the second. True to its name, the flowers open in the evening. Evening primroses also have a deep tap root. Another attractive wildflower for waste areas, they produce massive amounts of seed and can be invasive.

Dame’s rocket (Hesperis matronalis), a European import, looks like wild phlox, but if you examine its white, pink, or purple flowers you will notice that each floret has four petals, not five like phlox. Also, its lance-shaped leaves are “toothed,” while phlox leaves have smooth edges. Dame’s rocket is a 3- to 4-feet tall, pretty weed that flowers in May and June. It is often sold in packets of mixed wildflowers. Like other weeds, dame’s rocket spreads aggressively through seeding.

How to control them
Control of all these pretty weeds consists of pulling when possible. Learn to recognize the young seedlings—especially those with deep tap roots that are difficult to remove. You can also cut off the flower heads of older plants before they go to seed. Bag and dispose of these flowers—do not compost!—to prevent seed development and dispersal. Use herbicides as a last resort.

Article written by Judy Deutsch, Extension Master GardenerSM Volunteer.

Contact Us

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

Events

Keep up with our events by subscribing to the blog or checking our Events Calendar.

Explore the Archives

Back to Top