[invasive.org] Description, Ecological Threat: Appearance Taraxacum officinale is a perennial that grows best in moist areas in full sun. Its strong taproot is capable of penetrating the soil to a depth of 10 to 15 ft. (3 to 4.6 m), but it is most commonly 6 to 18 in. (15.2 to 45.7 cm) deep. Taraxacum officinale can be a major weed problem for turf and ornamental managers. In turf, it forms clumps that cause poor footing for athletic fields and golf courses. When this plant infests turfgrass and ornamental plantings, it forms dense circular mats of leaves that crowd out desirable species and reduce the vigor of those plants that survive. (link added by Mary Ann Machi)