Dahlia ‘Ragged Robin’ (dahlia tuber) £4.99
Position: full sun Soil: fertile, humus-rich soil Rate of growth: average Flowering period: July to October Hardiness: half hardy Now fashionable again, dahlias are useful for extending the season of interest in a perennial border, when everything else is past its best. Ragged Robin has dramatic, pointed, ruby red petals that are arranged in several layers around the yellow centre. It looks great planted in bold groups with purple-flowering plants such as Aster novi-belgii Purple Dome, or as part of an exotic planting scheme. The flowers are produced from July until the first frosts. 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 ‘eyes’ 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.