All in good time.
Just as the garden begins to go over, we have spring to look forward to, and what better way to bring spring closer than planting bulbs.
Bulbs should be hard and dry when purchased, their outer layers papery. They should be kept in a cold, dry, airy place until you are ready to plant them. Any that are soft, or showing mould, should be discarded. Now is a perfect time to be planting spring bulbs, but there’s no need to panic yet. A survey by Gardening Which? showed that planting in September and October gave best results, but planting as late as December will still result in worthwhile blooms. Tulips are best planted a little later, from late October to December when the soil is cooler. This reduces the risk of viral and fungal diseases, in particular Tulip Fire. This dreaded fungal disease affects only tulips, but it will contaminate the soil, infecting healthy bulbs planted in the same site for years to come.
A common mistake when planting bulbs is not planting deeply enough. This is one cause of bulbs “coming up blind”, or failing to flower, in subsequent years. A rough rule of thumb is to plant the bulb with twice its depth of soil above it. That means making a hole three times the depth of the bulb. Too deep is better than too shallow. In the case of crocus bulbs, which are irresistible to small rodents, very deep planting is essential.
Once planted, they will grow roots and establish themselves in the ground. Then follows a period of chilling while starch in the bulb is converted to sugar, and other changes take place. The chilling period varies from species to species; narcissi and tulips need 12-16 weeks, crocus and grape hyacinths need less. Narcissus tazetta and its cultivars are an exception to this and require no chilling. This quality, and their fragrance, has led to the popularity of Paperwhite, Grand Soleil d’Or and Ziva as indoor flowering bulbs. Once the chilling period is complete the bulb will start to make leaf and flower growth and emerge from the ground. It is thought the dormancy enables flowering at a time when there is less risk of frost damage to the bloom, and more chance that early pollinating insects will be active.
To prevent the bulb wasting energy developing seeds, the flowers should be deadheaded as they fade, either by snapping off the developing seed pods or by removing the whole stem. However, this is not practical with small bulbs like snowdrops or grape hyacinths, both of which seed freely.
The leaves of flowering bulbs should not be removed until they have turned yellow, collapsed, and died naturally. This is important as the photosynthesising leaves are providing nutrients to the bulb below. In the case of tulips a ring of baby bulbs develops around the mother bulb. These are too small to flower next season, but need all the nutrients they can get to develop and flower in subsequent years. Daffodils behave slightly differently; the original bulb will split at the base and another bulb (or two) will develop. These are called noses, and both should flower the following year. If you wish, you could sprinkle a light feed of general purpose fertiliser around your bulbs at this time.
All plants in the daffodil family contain a poison (lycorine) in their bulbs and leaves. This gives the plant some protection against predation and parasites, but can also cause skin problems in flower pickers and florists who regularly handle the plant material. Cut daffodils are best in a vase on their own. If added to a mixed arrangement, they can shorten the vase life of the other blooms. In contrast, tulips are not toxic. Indeed, during the Dutch famine of 1944-45 tulip bulbs were commonly consumed.