Photo: Howard F. Schwartz, Colorado State University, Bugwood.org, dandelion, Taraxacum officinale
Dandelion (Taraxacum officinale) produces a deep taproot, which makes hand removal difficult for established plants. Leaves grow in a basal rosette. Mature foliage is deeply toothed with the teeth pointing back towards the base of the plant. The yellow flowers are borne on leafless stalks. Depending on the weather, flowers can start forming as early as late March and continue on into fall. Dandelions reproduce through seed production. Seeds can be produced without pollination. Each seed is found within a light brown fruit (achene). The achene is attached to a feathery pappus by a small, slender stalk. Together, they form the wind-blown complete seed that is so common on a windy day. The foliage, flower stalks and taproot produce a milky fluid when cut or broken.
Mulch can be used as a non-chemical management option. Herbicide options for landscapes or nurseries include the pre-emergenents: dichlobenil (Casoran); flumioxazin (BroadStar - nursery/SureGuard); indaziflam (Marengo/Specticle); oxyfluorfen + oryzalin (Rout); oxyfluorfen + pendimethalin (OH2); oxyfluorfen + prodiamine (Biathlon). Post-emergenent herbicides for landscapes or nurseries include: clopyralid (Lontrel); diquat dibromide (Reward); glufosinate-ammonium (Finale); glyphosate (Roundup and others); and paraquat (Gramoxone, restricted-use).
For dandelions in turfgrass, any of the post-emergent herbicides containing 2, 4-D, florasulam (Defendor); metsuluron; or triclopyr + clopyralid (Confront) are effective. Treatments made in last summer or early fall provide the best control of perennial broadleaf weeds.
Remember to always read the label for proper application sites and rates.