Agapanthus prefers a neutral, well-drained, moderately fertile soil4. Soil that is too rich promotes lush, soft growth that is prone to winter damage4. Keep in a warm position, sheltered from wind. This is a waterwise plant that tolerates a variety of sun conditions – from full sun, to shade, although some sun is needed for optimal blooming. If your climate is very hot, try growing under partial shade conditions4. Keep well watered during the growing season. Yellow leaf tips indicate overwatering4.
Follow a regular watering schedule during the first year’s growing season to establish a deep, extensive root system4. After that, it only needs water when the top 3 inches (~7 cm) of soil is dry4.
Divide the clumps every 3 years or so, in spring4.
For a neat appearance, remove old foliage4
Keep in mind when planting that Dark blue is thought of as hardy, so it can be safe to leave outdoors for the majority of winter (although if in doubt, using a row cover is often a good idea).Propagation from seed is a slow process. Sow the seeds in late summer to autumn, in warm climates, or early spring in colder regions.
Seed should be sown in deep (10 cm) trays (as they will stay in these trays for at least a year), in a mixture of equal parts river sand and fine compost, and kept semi-shaded and moist. Fresh seed germinates readily within 6 to 8 weeks2 but can take up to 3 months4. Germination can be erratic: between 30 to 90 days. The majority come up at 30 to 50 days, but don’t throw away the pots too soon, you may have a couple of “latecomers” 3.
The seed should be sown thinly as the seedlings will stay in the tray for their first year. Seedlings should be potted up into individual containers during their second year and can be planted into the garden or permanent pots in their third year. Flowering can be expected from their third or fourth year2.
1 :The South African Gardener’s Survival Manual; first published 1985