Milk thistle (Silybum marianum) can be a pain if it's growing in your yard. It's non-native and can be an invasive plant, as Keri Wilson, horticulturist and writer for Garden Media Group ...

European marsh thistle, a terrestrial and wetland herbaceous biennial in the Asteraceae family, is an invasive plant that prefers moist soils. European marsh thistle frequently invades fens, wetlands, ...