Flowers: Summer

Height: 12 feet

Hardiness Rating: 8 9 10

Germination: Easy

Aftercare: Easy

Description: No wonder this is also called Tower of Jewels or 'Pride of Tenerife! Exceptionally tall flower spikes packed with either rose or purple-blue flowers, interspersed with silver-green lanceolate leaves.

Sowing Instructions: Sow 3mm (1/8in) deep in good seed sowing compost from late May-late July. Germination takes 7-14 days at 18-20C (65-70F).

Growing Instructions: When large enough to handle, transplant the seedlings to 7.5cm (3in) pots and over-winter in a cool greenhouse, conservatory or on a well lit windowsill with a temperature of around 7C (45F). Plant out the following spring 1m (3ft) apart, into a sunny site with well drained soil.

Aftercare Instructions: Although this species is proving to be quite cold hardy, its best to cover the base of the plants with a little bracken or similar over the winter. They can also be grown in 30cm (12in) pots to flower in a conservatory or cool greenhouse.