The window of opportunity for planting bulbs to flower for Christmas and New Year may be closing, but there’s still time to plant beautiful displays that will bring colour and fragrance into your home during the cold, dark days of January and February.
Planting, chilling and forcing bulbs
When we force bulbs, we are in effect giving them enough of a taste of winter to convince them that it’s spring in the warmth of our homes, so they bloom sooner than they might naturally.
Hyacinths and Paperwhite Narcissi are popular plants to force in time for Christmas, however we can force an array of spring bulbs to enjoy indoors during winter.
We achieve artificial winter with hyacinths by immersing them in total darkness in a cool place (preferably below 10℃). The lack of light is important for hyacinths as it encourages the flowering shoot to grow away, so that it won’t open in the neck of the bulb.
Crocus don’t require darkness, but they should be kept in a cool place for eight to ten weeks. Muscari and Narcissus require around ten weeks of cold. Iris reticulata should be placed in a cool and dark place for ten weeks.
Forcing prepared hyacinth bulbs
Prepared hyacinth bulbs have been temperature treated to force them to flower sooner. Plant them in containers and place in a cool, dark place for eight to ten weeks. Hyacinths that have not been treated may also be forced, but they will need between eleven and fourteen weeks in a cool, dark place.
When the shoots are around 7.5cm (3”) tall, check that the neck of the bulb is narrow and that the flower part is away from the bulb. Place the container somewhere cool and shady for a week to allow the leaves to become green and begin to open to reveal the flower, before moving the container to brighter light in a warmer location.
Removing spring bulbs from their artificial winter too early may cause the leaves to grow so fast that they hide the flowers, and the plants need staking.
How to force bulbs for indoor displays
- Select bulbs that are firm and large – the bigger the bulb, the bigger the bloom. Avoid any that are soft, show signs of disease, or have damaged outer layers.
- Choose a container – it’s all part of the display. I grow indoor bulbs in dishes, glass cube vases, terracotta bowls, lined baskets, and wooden seed trays. If the container has no drainage holes, use bulb fibre. If there are drainage holes, use a loam-based medium mixed with grit – I sometimes use the grit as a decorative mulch as well.
- Plant bulbs with their growing tips just nosing through the compost. Make sure that they’re close together, but not quite touching. Hyacinth bulbs can cause itchy reactions in some people, so do wear gloves when handling them.
- Water them in, then place them somewhere cool, and, if the bulbs require it, dark. Water if necessary – while they don’t want to be sitting in water, they mustn’t dry out. When they are brought into the warmth, they’ll require more water. If they dry out at this stage, unopened flower buds may fail to develop.
- When siting containers, consider the bulbs’ requirements. Iris reticulata will last longer if they’re in a cool room. Daffodils need more light than hyacinths, so place them in a sunny position to prevent them becoming too tall. Rotate containers if plants lean towards the light.
- After flowering, cut off the old flower heads, and plant hardy bulbs outside when the soil is workable. Paperwhites aren’t hardy, so either dry them and replant in early autumn, or leave them in their containers.
In addition to those in decorative containers, I grow some bulbs in plastic plant pots as they allow me to select those that look as if they’ll come into flower at the same time, so that I can arrange them together in containers for the house. If too many bulbs are ready at once, hold some back by keeping them cool for a while longer.
What are the best bulbs to force?
It’s possible to force a wide variety of hardy spring flowering bulbs, but below are a few of my favourites:
- Anemone blanda
- Muscari armeniacum
- Iris reticulata
- Narcissus – ‘February Gold’ or ‘Snow Baby’
- Scilla siberica
Indoor bulbs present a wonderful opportunity to be creative. From a simple and beautiful bowl brimming with Iris reticulata, to a miniature tabletop landscape of colourful flowers mingling with decorative twigs and cones, spring bulbs can be used to create varied and uplifting indoor winter displays.