Three species of sow thistle grow in Florida — spiny sow thistle (Sonchus asper), common sow thistle (Sonchus oleraceous) and field sow thistle (Sonchus arvensis) — but none is the type of plant most people want in their yard.
Even though all three species are edible, the broad leaves of these weedy members of the Aster family have sharp prickly edges that can poke and scratch skin. Like its dandelion cousin, sow thistle also bears yellow flowers. However, instead of growing low to the ground, sow thistle grows tall — up to six feet high — and each plant produces dozens of small daisy-like flowers that are not particularly showy.
As springtime progresses, the yellow flowers turn into fluffy white seedheads, which contain tiny brown seeds tethered to miniature white parachutes. When wind blows, the fluff takes flight carrying the attached seeds wherever the breeze takes them.
Source: Orlando Sentinel