Plumbago: Greenhouse Plants
C – cool, minimum of 7°C (45°F) / T – tropical, minimum of 18°C (65°F)
Plumbago capensis from South Africa makes a lovely climbing plant for the cool house. Ideally they should be planted out but will still flower as small plants in pots. The beautiful clear blue flowers are freely produced in late summer, almost covering the whole plant. There is also P. c. ‘Alba’ the white form which is just as enthusiastic a flowerer. However, be careful to plant it where its white flowers will stand out; I had one once that flowered against the sky which was invariably white and consequently the flowers never showed up. After flowering, the plants should be cut back hard to within a few nodes of older wood. Do not, however, make the mistake of pruning old plants too hard or they will do little more than send out a few wispy shoots from the old wood. Cuttings 8-10 cm (3-4 in) long should root with no trouble at 21°C (70°F) and plants will flower in their second year from spring sown seed placed in 21-24°C (70-75°F). There is a tropical species cultivated; P. rosea from the East Indies which is a smaller growing non climbing plant with bright pink flowers. This plant is best propagated by. To do this, 4-5-cm (1-½ – 2-in) lengths of well-formed roots should be placed just under the surface of some cutting , watered in and kept warm and humid. In time small plants will grow out of the roots which can then be grown on separately. I prefer to grow three plants in a 15 or 18 cm (6 or 7 in) pot. The flowers are produced throughout the summer. When flowering has finished cut the plants back hard and they will build themselves up to flower again.