MONTY’S PLANT OF THE WEEK
The purple florets of V. bonariensis add the character of a rich meadow to a border. It stands up to 2.5m tall in rich soil yet is never dominating. It is not fully hardy, but in a mild area will survive winter and emerge in a bedraggled state. It should then be cut back, ready to regrow. The plants are easy to treat as biennials, sowing in May to flower in July the following year, although they often behave like an annual, flowering in the autumn of the same year and self-seeding in unlikely places. V. bonariensis performs best in open sunshine, with rich, moist but well-drained soil.