Blooming Marvellous with their fantastical flowers

Diary of a Dorset garden

Hippeastrums are the big, fat, trumpet-shaped flowers that most of us (wrongly) still call amaryllis.

As crocus, daffs and tulips disappear from the shelves of our local garden centre, these huge, beefy bulbs take their place. In flower, they look as though they've wandered off the set of Walt Disney's Fantasia. You can scarcely believe that any flower can be so vast, so stiff, so voluptuously unreal.

Once you get them started, they grow indoors at a phenomenal rate. I used to buy them as extra presents for our children, but I potted them up and got them going before I handed them over. By the time they took possession, the buds would already be poking out of the noses of the bulbs. From then on, there was enough action to engage them.

There was a time when hippeastrums, like potatoes, only came in two colours: white and a pleasingly shocking shade of red. The red was usually 'Red Lion' and the white 'Apple Blossom', which was actually a very pale pink. But partly because hippeastrums have recently become such popular cut flowers, there's been a very welcome explosion in the number of varieties available in garden centres at this time of year – almost 80 are listed in The Plant Finder (Dorling Kindersley £15.99).

You can see why professional florists like hippeastrums so much. They last a long time in water and you don't need many of them to make a dramatic display. But they have a useful trick to stop the stems collapsing. They run thin canes up inside each hollow stem before they put the hippeastrums in a vase. The cane should jam in at the top of the stem just under the flowers; if it does not, plug it in place by stuffing cotton wool inside the bottom of the fat stem. If you quickly wrap a wide rubber band round the bottom too, this will stop the stem splitting and curling, as dandelion stems do when you drop them in water.

But if you start off plenty of hippeastrums in pots now, there won't be any need to take the more expensive option of buying them as cut flowers. Experiment instead by planting the bulbs themselves in tall, thick glass vases. You need to be careful about watering, as there will no holes at the bottom, but the final effect is wonderful, very spare and spacey. Add slender twigs of beech, twisty willow or branches of catkin if you want a fuller effect. You can stick the stems straight in the compost.

Last November, I planted seven amaryllis, all new to me, and found that some were very much quicker into flower than others. It's difficult though to find out whether earliness is an inherent trait in some varieties (as it is with hyacinths) or whether some small difference in aspect, feeding, watering or temperature advanced some and retarded others. Or whether the earliness has something to do with the way the bulbs themselves are prepared, before they hit the shelves.

Of the seven I planted last November, 'Aphrodite' was the earliest, flowering in late January and 'Pink Floyd' the latest, in flower by early March. The two could scarcely be more different. 'Aphrodite' is a creature of the boudoir, a powder puff of a flower, one of many variations on the pink and white theme, but double. Each flower looks like three single flowers, one fitted inside another with the petals of the innermost slightly narrower than the outer ones. The background colour is creamy-greeny-white, each petal finely edged and flushed with pink. It is the absolute antithesis of a hippeastrum such as 'Pink Floyd' or 'La Paz'. You miss the elegant stamens, here transformed to petals. I had two stems from one bulb, with four flowers on the first stem, two on the second. As they age, they grow out on their stalks and hang heavily down. It was bred by the Miyake Nursery in Japan and introduced in 1994.

'Pink Floyd' is about the same height as 'Aphrodite' (60cm), but the flowers emerge as long, thin trumpets, elegant in form. They are very different in style to the typical wide, flat-faced flowers of most hippeastrums (I'm thinking of 'Black Pearl' or 'Picotee'). Each trumpet is 15cm long, green where it joins the stem, then flushing to deep pink, with an indistinct white stripe down the centre of each petal. The stigma explodes in a three-curled flourish, with cream anthers ranged behind it.

My favourites are the hippeastrums that look like orchids: H. papilio, 'Chico', 'Emerald', 'La Paz'. Fortunately, it is this type that breeders seem to be keenest on too. There's a new one out this year called 'Lima', deep burgundy and green, that I've just bought and am longing to see in flower. Hippeastrum papilio comes from southern Brazil (most hippeastrums originate from South America) and has buds larger and flatter than any other type I've grown. The flowers seem narrow, when viewed from the front, but the petals arrange themselves in an interesting way, the three upper petals much wider than the three lower ones. The colour is bizarre, a kind of pale, creamy green, striped with maroon. In front of the bottom-most petal, the stamens and pistil hang down in a louche, self-confident way. It's stunning.

Big is not always best, but with hippeastrums, it pays to get top-size bulbs. Kits, containing pot (usually hideous), compost and bulb are not such good value as buying bulbs on their own. Check that each bulb is firm, that its nose is not damaged and that it has plenty of fleshy roots. Soak the roots for 12-24 hours, by balancing the bulb on top of a jar of tepid tap water. Do not get the base itself wet, or it may rot.

Choose 15cm pots for smallish bulbs (though small is a relative term here, 28-30cm around the waist of the bulb), 18cm pots for medium-sized bulbs (30-34cm) and 20cm pots for big ones (34-38cm). You do not need to leave much space between the edge of the bulb and the edge of the pot, but the deeper the pot the better. Plastic is easier to manage than terracotta (though does not look so good). The pots must, of course have drainage holes.

The compost you use must be nutritious and free-draining. The Royal Botanic Gardens, Kew, which puts on spectacular winter shows of hippeastrums in its glasshouses, makes up its own special mix: 45 per cent coir, 45 per cent Sylvafibre (composted twigs and bark) and 10 per cent loam, with added slow-release fertiliser. I have had decent results simply by mixing multipurpose compost with gravel or grit (two parts compost to one part grit). Add a slow-release fertiliser (such as Osmacote granules) to the mix.

Put a layer of your compost in the bottom of a pot. Hold the bulb in one hand with its roots hanging down and firm more compost round the roots. The nose of the bulb should poke up above the rim of the pot and its shoulders should be above the surface of the compost. Water with tepid water and put the pot in a warm, light, well-ventilated place, free from draughts. A temperature around 21C is ideal.

Let the compost dry out on top before watering. Always water from the top, never from the bottom. Do not wet the nose of the bulb or allow the pot to stand in water for a long period. When the first shoot appears, start feeding by adding a liquid fertiliser when you water. Give the pot a quarter turn each day to keep the stems growing straight. You may need to stake them as they grow. When the buds start to open, move the pot to a cooler place so the flowers last as long as possible. Suppliers suggest that hippeastrums will come into flower six to eight weeks after planting. They have never been that fast for me. Ten weeks is more realistic.