Written By Mary Free, Extension Master Gardener
Most people, adults and children alike, recognize the dandelion, but how well do they really know it? The dandelion is one “nasty” plant–that is, one displaying nastic movement. Dandelion flowers open after the sun rises and close as the sun sets in response to the intensity of light (nyctinasty). At higher temperatures, they open in response to light (photonasty). At lower temperatures, they open in response to temperature (thermonasty).
Dandelions, which can emerge as early as February, provide nectar to bees and butterflies, especially important early in the season; seed for songbirds; food for chipmunks, rabbits, quail, turkeys, and deer; and nesting material for hummingbirds. From antiquity until the 20th century, dandelions were valued. The first settlers brought the seeds here and planted dandelions to use primarily for medicinal purposes and beverages. Then, attitudes changed with the increasing popularity of mowed lawns and advancements in no-till farming. Adults suddenly regarded the dandelion as a nasty weed. Unlike some other “weeds,” dandelions do not damage the ecosystem; however, the herbicides landowners use to try to eradicate them can.
Two different species, both non-native, grow in our area: Taraxacum officinale (common dandelion) and Taraxacum erythrospermum (red-seeded dandelion). Their flowers look similar–a solitary, yellow head of ray florets atop a leafless, hollow stalk–but their leaves set them apart. Both form a basal rosette with entire to deeply lobed, toothed leaves and a tap root. However, the leaf shape of the common dandelion is irregular and variable with the uppermost lobe larger than the others, while red-seeded dandelion leaves are narrower with sharply triangular lobes.
Another distinguishing feature is their fruit. If you have been reading this year’s Word of the Week posts, then you know that members of the Asteraceae plant family produce single-seeded fruits called cypselae. The common dandelion cypselae are light-to-greenish brown; the red-seeded dandelion cypselae are–you guessed it–red (actually reddish-to-purplish brown).
Dandelions spread by seed: 3,000 to 23,000 per plant, according to Ohio State University. Each cypsela attaches at one end to the flower receptacle and at the other end to a fine filament, or beak, that connects to a silky tuft of hair, or pappus, and when released can waft in the air for miles. When the seeds land, the spines on the cypselae help anchor them to the soil. These seed heads or “blowballs” may have entertained you as a child, but as an adult they may send shivers down your spine if you think of each seed becoming a plant that you may someday feel the need to weed.
Dandelions are perennials; they can live undisturbed for over ten years. With age, the tap root grows thicker and longer (6–18 inches long) and becomes more difficult to remove in its entirety. Weeding when the soil is moist and with a specialized weeding tool will improve your chances of getting the tap root out intact. If you do not remove all of the tap root, new plants can grow from fragments as small as one inch. The upper part of the tap root attached to the crown is more viable, so try to dig up at least the first four inches. If you break the tap root, then a three-inch layer of shredded bark mulch over the area will smother any new vegetation that may emerge and eventually starve the root. Using landscape fabric and covering it with mulch is also effective. Mulch application is more feasible in a garden, along a fence border, or under a tree than in the middle of your lawn. In your lawn, cover any holes left by weed removal with soil, then follow good lawn management practices.
Mowing may cut down some flower stalks to prevent seed production, but it will not curb dandelion growth, because the basal rosette’s prostrate form lies below the ideal height for mower blades. However, a dense, well-maintained lawn will slow growth. In summer, mow at the upper-range height for your specific grass species. Higher turf (three to four inches) will help shade out sun-loving dandelions as well as inhibit crabgrass. If you see seed heads emerging, pick and trash them before seeds disperse. Use herbicides as a last resort. Fall applications are usually more effective than spring, as the chemicals are more likely to be absorbed by the roots. (See Fall lawn weed control strategies.)
Whether you decide to weed dandelions or not, try the leaves in salad–chop them into small pieces and sprinkle them over other mixed greens–or sauté them with garlic and olive oil for five minutes, then add some stock to the pan and steam/boil until tender. This way the bitterness won’t overwhelm your taste buds. The youngest plant leaves, those picked early in the season before flowering or after first frost, and those from shady spots are supposedly less bitter. Dandelions can be made into a number of beverages: beer (from leaves and roots); a coffee-substitute (from roasted roots); and wine (from flowers). The flowers, which are somewhat sweet, can also be eaten raw, or breaded and fried, or used to make jellies.
Both species are fully edible and nutritious, but make sure that the plants have not been exposed to herbicides, pesticides, or other chemicals or high human or animal traffic; and wash them well. They should be eaten in moderation, because the leaves are rich in oxalates. Dandelions contain latex, so those with latex allergies should take care.
*Dandelion comes from the French “dents de lion” or “teeth of the lion,” referring to its jagged leaves. Blowball or puff ball refer to the puffy seed head that children like to blow on so they can chase the seeds as they fly away. Pissabed refers to the dandelion’s diuretic properties and what could happen if you eat them before bedtime.
D’Costa K. 2017. The American Obsession with Lawns. Scientific American.
Dandelion (Taraxacum officinale). Ohio Perennial and Biennial Weed Guide. Ohio Agricultural Research and Development Center. © 2021. The Ohio State University. [accessed 2 Apr 2021].
Fall lawn weed control strategies. Virginia Cooperative Extension. © 2021 Virginia Polytechnic Institute and State University. [accessed 2 Apr 2021].
Roncoroni JA. 2018. UC IPM Pest Notes: Dandelion. UC ANR Pub 7469, Oakland, CA.
Tanaka O, Tanaka Y, Wada H. 1998. Photonastic and thermonastic opening of capitulum in dandelion, Taraxacum officinale and Taraxacum japonicum. Journal of Plant Research 101:103–110. https://doi.org/10.1007/BF02488887.
Taraxacum officinale (Common Dandelion) and Taraxacum erythrospermum (Red-seeded Dandelion). MinnesotaWildflowers, a field guide to the flora of Minnesota. © 2006-2021 MinnesotaWildflowers.info. [accessed 2 Apr 2021].