Val Bourne on the muddle surrounding these bulbs and how to care for them

The Chelsea Flower Show, held in late-May, always produces some show-stopping moments and, although television coverage always majors on the 20 or so show gardens, Chelsea will always be about the plant exhibits for me. It’s The Great Pavilion, the covered space where nurseries and botanical societies from all over the world stage breathtaking exhibits, that excites me. And it’s the exceptional people who produce them who are the true stars of Chelsea, not the highly-paid garden designers.

Last year was the hundredth anniversary of the first Chelsea Flower Show. A display of alliums, ornithogalums and amaryllis, staged by the Dutch family-run bulb company Warmenhoven, won the Diamond Jubilee Award for the best display in the Great Pavilion. This new award, introduced to celebrate the Queen’s diamond jubilee in 2012, was won by Hyde’s Lilies in 2012.

I was lucky enough to be at Chelsea during the Queen’s Jubilee year. She toured the show, resplendent in lavender but without her trademark hat. Instead she wore a black net affair studded with black appliqué daisies that looked wonderful against her grey hair. As the Queen made her way round the marquee a regimental band, hidden among the shrubbier exhibits, waited for their moment. As soon as she came into view they struck up and regaled her with God Save the Queen. Her majesty’s delight and surprise was palpable.

The Warmenhoven family deserved to win with their heritage amaryllis from one hundred years ago rubbing shoulders with modern cultivars. They were strung above the exhibit to form a multicoloured ceiling that allowed you to loom, straight into their trumpet flowers. I still don’t know quite what Warmenhoven were displaying though, because the name amaryllis is used for the South African bulbs and the huge Hippeastrums of South America.

There’s always been confusion about these two. Botanist Carl Linnaeus (1707-1778) named the South African bulb Amaryllis equestris, probably because part of the flower structure looked like a horse’s head with ears. Dean William Herbert (1778-1847 ), realising that A. equestris was not a true amaryllis, kept the horsey connection and coined the name Hippeastrum, literally the Horseman’s Star. However amaryllis is still used by gardeners and nurserymen, causing great confusion. Hippeastrums were first introduced in the 1770s and were soon being hybridised.

Mr Johnson of Prescot in Lancashire crossed the scarlet-red H. reginae with the striped red and white H.vittatum to produce H. x johnsonii in the mid-1770s. Some of these bulbs were passed to the Liverpool Botanic Garden and this hybrid still exists today, although it’s been followed by hundreds more. October to January is the perfect time to plant Hippeastrums and they should flower about six to eight weeks after planting.

The technique is to plant the huge bulbs into slightly bigger pots containing a good compost (like John Innes 2) so that the neck and shoulders of the bulb remain above the surface. Keep the bulbs in a well-lit warm space at 21C (70F), the average temperature of most warm room. Water sparingly until the new leaves develop and then water regularly. Do not let the compost dry out, but avoid excess water collecting in the saucer. Once the flowers appear, move your plant to a cooler place (15-18C (60-65F), to extend its flowering period.

If you want to keep your bulbs for another year apply a liquid plant fertiliser every week and then put the bulb, still in its pot, in the greenhouse or the summer, or outside in the garden in semi-shade. Full sun scorches the foliage. In late-September move your pot somewhere cool with temperatures of 13C (55F) for eight to ten weeks. Stop feeding and reduce the watering so that the plant becomes semi-dormant. Cut the remaining old leaves to 10cm (4in) from the neck of the bulb and replace the top 2.5-5cm (1-2in) of compost. Re-pot every three to five years in January to March after flowering: they resent disturbance.