The carrot family contains an unexpectedly wide range of annuals, biennials, perennials and shrubs ... Care For best results when growing eryngiums, plant in spring or summer.

Fallow may also be used to control perennials such as Canada thistle and perennial sow-thistle. With these species, the first tillage should be done at the bud stage. Food reserves are at a low at ...

the plant is unaffected. No other thistle species in New Zealand is a perennial. Other species are either annuals or biennials, all with tap roots. Only the Californian thistle has horizontally ...