Common name: Honeywort
They grow to around 500mm (18") high with a similar spread.
It is a useful plant for attracting bees into the garden.
It is a prolific self seeder so deadhead regulary if you do not want it multiplying every year.
Allow a few seedheads to dry off then collect them and store for future use!
Week 14: Sow seeds in pots/trays of seed compost and germinate at 18°-20°C (64°-68°F)
Germination should take about a week.
Week 16: When seedlings are large enough to handle prick out into trays/boxes of potting compost and grow on at 10°- 12°C (50°-54°F) for a week to ten days, then place in a coldframe to harden off until planting out time.
Week 22: Plant out 300m (12") apart in a sunny position in any fertile garden soil.