Dandelion-Sunflower Family

Lion’s-tooth, blow-ball, cankerwort, puffball, milk witch, yellow gowan, witch’s gowan, door-head-clock, common dandelion

Taracacum officinale

Characterisitics. This European perennial weed is now one of the most common pests in turf in the US. It is most commonly found in moist soil including lawns, meadows, pastures and overgrazed areas. It is considered valuable as a forage source and is especially favored by sheep and cattle. It has a deep taproot (several feet in some cases) and easily regrows if the root is not removed. Flowering occurs almost 9 months out of the year. The windblown seeds germinate in spring to early summer, or year round in irrigated landscape environments. The genus is somewhat confusing with hundreds of species names published. Dandelion is a widely distributed perennial broadleaf weed found throughout California, except in deserts, to about 11000 feet  (3300 m). It consists of a complex of biotypes that vary with environmental conditions and is a common weed of mountain meadows and turf, especially in southern California. It also inhabits perennial crop fields, especially those in alfalfa, disturbed sites, and nurseries. It is a host of aster yellow disease, which affects a number of vegetable crops. Because dandelion contains high amounts of certain minerals, it serves as a complement to pasture forage for livestock. In addition to being weedy, the fine hairs of the one-seeded fruit can clog cultivation equipment.

Identifying Characteristics. Cotyledons (seed leaves) are oval, hairless, and have a midvein that terminates with a gland at the leaf tip. The first and next few leaves are football shaped to oblong, taper at the base, and have weakly toothed edges. Later leaves are widest near the tip with gradually tapering bases and sparsely-toothed edges. Young leaves form a basal rosette. Mature plants have no visible stem. Leaves are sparsely hairy or hairless, with deeply serrated edges, and cluster into a rosette at the base of the plant. A strong, deep taproot exudes a milky substance when cut. Dandelions flower nearly year-round in mild climates. The bright yellow flower head is 4/5 to 1-2/5 inches (2–3.5 cm) across and is found singly on the tip of a hollow, leafless stalk that is 3 to 12 inches (7.5–30 cm) tall. The flower head consists of many, small, yellow, petal-like flowers (ray flowers).A tiny, brown, one-seeded fruit (achene) about 1/10 of an inch (3 mm) in length is attached to a long, slender stalk, terminating in a parachute-like structure (pappus) consisting of hairs. Collectively the fruit form a fuzzy, gray-white, spherical fruiting head.

Dandelion flowers are 1 to 2 inches across, solitary (one per stem) and composed of petal-like flowers.

Dandelion seed heads form a white sphere, which disperses with a slight breeze.  The pappus, or white cotton-like substance attached to the seed, aids in wind dispersal.

A number of species of Taraxacum are seed dispersed ruderals that rapidly colonize disturbed soil, especially the Common dandelion (T. officinale), which has been introduced over much of the temperate world. After flowering is finished, the dandelion flower head dries out for a day or two. The dried petals and stamens drop off, the bracts reflex (curve backwards), and the parachute ball opens into a full sphere. Finally, the seed-bearing parachutes expand and lift out of it. The parachute drops off the achene when it strikes an obstacle. After the seed is released, the parachutes lose their feathered structure and take on a fuzzy, cotton-like appearance, often called "dandelion snow"^{[citation needed]}.

Dandelions are so similar to catsears (Hypochaeris) that catsears are also known as "false dandelions". Both plants carry similar flowers, which form into windborne seeds. However, dandelion flowers are borne singly on unbranched, hairless and leafless, hollow stems, while catsear flowering stems are branched, solid and carry bracts. Both plants have a basal rosette of leaves and a central taproot. However, the leaves of dandelions are smooth or glabrous, whereas those of catsears are coarsely hairy.

Other plants with superficially similar flowers include hawkweeds (Hieracium) and hawksbeards (Crepis). These are readily distinguished by branched flowering stems, which are usually hairy and bear leaves.

Uses-Medical. Dandelion leaves produce a diuretic effect while the roots act as an antiviral agent, appetite stimulant, digestive aid, and may help promote gastrointestinal health. Dandelion flower has antioxidant properties. Dandelion may also help improve the immune system.

Health care providers clinically use dandelion root to promote liver detoxification and dandelion leaves to support kidney function.

Dandelion is a natural diuretic that increases urine production by promoting the excretion of salts and water from the kidney. Dandelion may be used for a wide range of conditions requiring mild diuretic treatment, such as poor digestion, liver disorders, and high blood pressure. Dandelion is a source of potassium, a nutrient often lost through the use of other natural and synthetic diuretics.

Fresh or dried dandelion herb is also used as a mild appetite stimulant and to improve upset stomach (such as feelings of fullness, flatulence, and constipation). The root of the dandelion plant is believed to have mild laxative effects and is often used to improve digestion. Research suggests that dandelion root may improve the health and function of natural bacteria in the gastrointestinal tract. Studies have also reported that dandelion root may help improve liver and gallbladder function.

Some preliminary animal studies also suggest that dandelion may help normalize blood sugar levels and improve lipid profiles (lowering total cholesterol and triglycerides while increasing HDL, "good," cholesterol) in diabetic mice. However, not all animal studies have shown the same positive effect on blood sugar. In addition, research needs to be done on people to determine if this traditional use for diabetes (see Overview) has modern-day merit.

Dandelion herbs and roots are available fresh or dried in a variety of forms, including tinctures, liquid extract, teas, tablets, and capsules. Dandelion can be found alone or in combination dietary supplements.

Characteristics Important in Control. Dandelion has a deep taproot and is difficult to physically remove. If any part of the root of this perennial is left the plant will readily regrow. Chemical applications are the most effective control. In mid- to late-spring, dandelions are at their worst. Those yellow flowers are everywhere, shortly followed by billowy seeds, ready for easy wind distribution around your yard. At this time of year, you might be tempted to pull out the weed killer big guns and treat your lawn with some serious herbicide. Unless you're willing to accept totally killing the weeds and the lawn, and then a complete new planting, step away from the sprayer.

The problem with a regular weed and feed or broadleaf perennial weed killer is that dandelions just aren't that susceptible to the poison in the spring. You'll have a much better shot at actually killing them in the fall, when they're waning for the season and will take the weed killer down to their roots along with their winter food supply. Spray in spring, and you'll have to spray again in summer, and fall. You can go ahead and treat the dandelions in spring--you'll get some results. Just don't go bonkers and spray and spray and spray in hopes of wiping them out in May.

A thick, healthy lawn is the best defense against dandelions and all other weeds. Fertilize your lawn, water it properly (deeply once or twice a week, not for shorter periods every day), and mow high. Last but not least, cut the dandelion heads into plastic bags before they spread seeds all over your yard. It takes a little time, but it will make a difference.