Dutch bulb experts share top tips for maintaining your garden. Hannah Stephenson reports
YOUR summer-flowering bulbs should be well on the way to blooming now, bringing a riot of colour to the garden and adding fragrance and form to patio planting. Lilies, dahlias, cannas and begonias can look amazing as stand-alone specimens in pots, while some can be successfully combined with other garden plants. Most summer bulbs are sun-lovers so are ideal for patio pots as they enjoy heat in a sunny spot.
A team of experts from The Joy Of Plants, an initiative from The Flower Council of Holland, have come up with tips to look after some of its favourite bulbs: the Zantedeschia (calla), hybrid potted lilies and the star of Bethlehem (ornithogalum)...
Bring summer-flowering potted bulbs indoors after flowering, in October or November, to give them a hibernation period whereby the plant remains dry and the foliage dies back. The bulbs and tubers will then produce plenty of new flowers during the next growing season. You can plant them outside again from April onwards to flower again in the summer.
Tuberous begonias: These like to be sheltered from wind, in partial shade, as the foliage can scorch in bright sunlight. They’ll also need to be fed regularly with a high-potash fertiliser and make sure you deadhead them as they fade, to keep the plant going.
If you want them to last through to the next season, store them in a frost-free place over winter. Once they’ve finished flowering, gradually stop watering them and they will die down. Cut stems down and lay the pots on their sides in a cool airy place, or take the tubers out and store them in dry compost until spring, when they should come back to life again.
Dahlias: Plant them in late spring outside in John Innes No. 3 compost in containers at least 30cm in diameter. Encourage bushy growth by pinching the tops out when the shoots reach 10-12cm and deadhead as they fade to encourage a long succession of flowers. Dahlias will be knocked back by the first frost, so once the top growth has gone, you can remove tubers from the pots, dry them and store them in a frost-free place until spring.
Lilies in pots: Again, planted in spring, many will be ready to flower in July and benefit from an occasional liquid feed with a high-potash fertiliser. Once blooms have faded, cut them off, but leave the stems and continue to water and feed to build up the bulbs’ strength for next year. The stems will die back naturally in late summer or autumn and the bulbs can be left in the same pots for a few years. After this time, replant them in fresh compost or in the border.
Agapanthus: Also known as lily of the Nile, these impressive globes of blue or white flowers look brilliant in pots and they like to be cosy, so don’t give them too much room and don’t replant too often as they like to be pot-bound. They need a hot, sunny spot to flower and a fair amount of moisture during the growing season. Put them somewhere sheltered, close to the house or under a porch, during the winter or the frost will catch the strap-like leaves, and they should come back year after year.
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