prickly sowthistle - sonchus asper

america angiosperms asper asteraceae asterales asterids bloom blooming blossom botany burlington canada canadian conservation creek environment environmental flora floral flowers grindstone hendrie horizontal horticulture invasive living marshes milk natural nature north ontario organism outdoors outside park petal plants pretty prickly rough sharpfringed sonchus sow sowthistle species spinyleaved thistle urban valley wild wildflowers yellow