This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Introduced. Perennial. Propagates by seeds.
Time of bloom: All months in the year, where the weather is not at freezing point. Most abundant in spring.
Seed-time: Seeds ready for dispersal within two weeks from the unfolding of the flower.
Habitat: Fields, meadows, lawns, waste places.
Wherever civilized man has established himself and cultivated the ground, he has carried and sown this weed, and, once in the soil, the Dandelion can be depended on to hold it. Drought does not affect it, the root being large, thick, fleshy, driven deeply into the soil, sometimes to a length of twenty inches; and cutting the crowns from the roots will not kill this weed as it does many taprooted plants; indeed, any part of a root will sprout leaves and make a new plant if buried in warm, moist soil. All parts of the plant are protected by bitter, milky juices which animals usually dislike, so that even in pastures it often thrives and reproduces itself unharmed.
Leaves basal, three inches to more than a foot long, blunt lance-shaped in outline but deeply and irregularly lobed and toothed, the divisions usually pointing toward the base, somewhat hairy when young but soon becoming smooth, spreading on the ground in a flat rosette; petioles margined and short. Scapes smooth, hollow, cylindrical, short at first but lengthening with maturity. Flower-heads often nearly two inches broad, deep golden yellow, opening only in fair weather, and closing and reopening several times before the whole colony is fertilized to the center; florets all perfect and fertile, the rays five-toothed at their tips; bracts of the involucre in two series, the outer ones short, spreading, often reflexed at maturity, the inner ones smooth, linear, erect in a single row, long enough to enfold the flowers after their first opening. Achenes brown, oblong, angled, and ridged, set around the top with fine, spinous tubercles, the tip extending in a slender beak, bearing a copious pappus of fine, white hairs. (Fig. 369.)
Fig. 370. - Dandelion (Taraxacum officinale). X 1/4.
Young Dandelion plants are excellent salad and pot herbs; the roots are used in medicine and more than a hundred thousand pounds are imported annually, notwithstanding the abundant home-grown product. The time for collection is in autumn when the roots are well stored with sustenance for the next season's growth, at which time the milky juice is thickest and the root most bitter. The price is four to ten cents a pound.
One method, and usually the one practiced in small lawns and often in large public parks, is the diligent, persistent use of spud or knife, cutting below the ground. The plants sprout again, and have to be cut again, but if no leaf-growth is allowed to feed the roots even old ones must finally starve. A pinch of dry salt applied to the root at the time of cutting off the crown, will retard recovery. But winged weeds are constantly "blowing in" to replant the ground, and seedling Dandelions, with taproots still short and slender and leaves finely hairy, may be killed with chemical sprays; old plants with long, well-filled roots and smooth leaves are not much if at all affected. But if lawns and parking are systematically sprayed throughout the growing season with Copper sulfate or Iron sulfate, the grass will not be injured, seedling Dandelions will be destroyed, and the hairy, opening buds of old plants will be injured sufficiently to check development of seeds. Too often it is forgotten that the plants of roadside and waste places must not be neglected, even though growing at some distance, if property-owners expect any degree of success in keeping out the intruder. "Everlastingly keep at it" must be the motto of one who fights this weed.