The basal foliage of the Italian eryngo is evergreen in milder climates and looks rather like leathery thistle leaves. In summer, the well branched stems carry small egg-shaped flower heads ...

You don't want to remove them by accident. Identifying traits of bull thistle Cirsium vulgare include lobed leaves that are furry underneath and spiny on top but don't have the marbled patterns ...

It is most likely to be confused with a closely related species called prickly sow thistle (Sonchus asper), which looks very similar but has more prickly leaves than the sow thistle. The lobes in each ...

Russian thistle can also be a host for insects that transmit curly top viruses, which stunt the growth of an infected plant and deforms its leaves and fruit. The plant's pollen is a potent allergen, ...

Scotch thistle is the most common thistle species in New Zealand with spines on both the leaf surface and margins. Scotch thistle is a biennial weed, so it depends quite heavily on the establishment ...

Bull thistle, a member of the Asteraceae family, is yet another herbaceous biennial on our list of invasives. Unfortunately, bull thistle can flourish in an array of sites ranging from meadows, ...