Although native to Europe, spiny-leaved sow-thistle is a common weed in North America.
It is also widespread in Africa, Asia, and Madagascar. In many habitats it is considered a nuisance, and
in some it is an invasive.
Identification: Plants reach 3' (1 m) in height. Leaves
are up to 6" (15 cm) long, and produce a milky sap when cut. Lower leaves are obovate or spatulate. Upper
leaves become more oval or narrow in shape. Leaf edges are spiny, and attached directly to the stem.
Clusters of yellow flowers, each ½-1" (1.3-2.5 cm) in diameter, appear at stem tips, appearing from May to
October. Fruits are brown and
wrinkly, about ⅛" (4 mm) around. They are surrounded by a white puffball. The flowers and the
puffballs are reminiscent of small dandelions.
Edibility: Handling plants can cause contact dermatitis for some people:
burning or redness, or rashes similar to those from poison ivy. However, younger plants harvested before spines
have formed are edible, with lettuce- or Swiss chard-like flavor. Older plants, though non-poisonous, become more bitter and must have the spines cut off.
(Thanks to Arpi Szabo for pointing out that sow-thistle is in
fact edible. Arpi is a Hungarian student of plant protection mastery writing from SAPIENTIA Hungarian University of Transylvania, in Tîrgu-Mureș, Romania.)