Position full sun soil fertile, humus rich soil rate of growth average flowering period july to september hardiness half hardy may need winter protection a decorative form that forms attractive mounds of deep purple foliage, which looks almost black in certain lights. From mid summer until the first frosts, this is topped with branching, upright stems, carrying single, near white flowers. The contrast is superb and will add real interest to the border. Alternatively, pot it up and place it on the patio, wher it will add a colourful splash for many months of the year. This is a cracking dahlia, that has been given the prestigeous award of garden merit from the royal horticultural society. Garden care dahlia tubers can be planted outside after frost, or started off in pots under glass in late winter to early spring. Plant them horizontally approximately 12cm deep, making sure the aposeyesapos are uppermost. Allow enough room between each tuber so the plants can grow and spread to their full size without being over crowded. While in growth, provide a high nitrogen liquid feed each week in june, then a high potash fertiliser each week from july to september. Stake with canes or brushwood if it becomes necessary. In mild areas, leave them in situ over winter, but protect the crown with a generous layer of dry mulch. In colder areas, carefully lift and clean the tubers once the first frosts have blackened the foliage and allow them to dry naturally indoors. Then place the dry tubers in a shallow tray, just covered with slightly moist potting compost, sand or vermiculite and store in a frost free place until planting out again.