Winner of the RHS Award of Garden Merit.
Height: 2m, Spread 1.5m
Flowers: June to July
Position: Sun to dappled shade in any soil
Packet of 40 seeds
Sowing Instructions: Sow at any time of the year. Sow very thinly in trays or pots of moist seed compost mixed with a little vermiculite and just cover the seeds with vermiculite. Seal inside a polythene bag and place the container in the fridge for 12 weeks.
[If sowing a large quantity, mix seeds with the compost/vermiculite and place in a resealable bag in the fridge, then sow into trays or directly outdoors in a nursery bed.]
Then move to a temperature of about 14-16C and germination should take place in 1 to 6 months. Throughout this process check regularly and ensure the compost does not dry out. Note: Germination can be very erratic, so sow thinly and prick out the seedlings as they become large enough to handle disturbing the rest of the compost as little as possible.
Alternatively, sow as above and place in a cold frame or sheltered part of the garden in autumn and let nature take its course – germination will begin in spring. Remember to protect pots from wildlife! I personally find this a very reliable and easy way to germinate seeds.
Transplant seedlings when large enough to handle into 7.5cm pots and grow on in plenty of light but shaded from direct sun. Harden off plants (move plants outdoors during the day and back in at night for 10 days) and plant out when large enough in a sunny spot with moist soil (dislikes very wet soil).