Posted by: Bystander PJ31 OCT 2012
Round about now, particularly in North America, many people are starting to grow paperwhite narcissi (Narcissus tazetta) to help brighten their homes over the yuletide festive period.
Unlike other narcissus bulbs, paperwhites do not need a chilling period, so forcing them is easy. Just keep the base of the bulbs in water and within two or three weeks you should have fragrant blooms. (However, be warned that not everyone enjoys the smell. Some say it reminds them of cat pee.)
A popular growing technique is to part-fill a container with pebbles, gently push in the bulbs and add water until it reaches half way up the bulbs, topping up as required. As a quirky alternative to pebbles, you could use other non-metallic substrates such as buttons or beads, or even Lego.
One problem with pot-grown paperwhites is that their tall stems are often not strong enough to support the weight of the flowers. The usual way to stop the blooms from falling over is to insert a stick into the pebbles and tie the plants to it with a colourful ribbon. But, perhaps surprisingly, another way to support the stems is to ply the bulbs with booze. Researchers in the flower bulb research programme at Cornell University have found that paperwhites grown in a dilute solution of alcohol reach no more than half the normal height, making them more able to bear the weight of the flowers. The blooms remain the usual size and last just as long.
The technique is to wait until the shoots reach about 3–5cm and replace the water with an aqueous solution of about 5 per cent alcohol, which you then also use for topping up. This is an ideal way for pharmacists to demonstrate their skill in calculating correct dilutions.
If you feel generous you can ply the bulbs with vodka or gin. But since they are just as happy with denatured alcohols such as methylated or surgical spirit, you can save the potable liquor for your seasonal celebrations.