Plant spring-flowering bulbs in a container by October to ensure they get the chill they need
Spring-flowering bulbs are temperature sensitive and require a minimum 15 weeks of cold weather in order to bloom. Make sure they get the requisite exposure to cold, however, they should not be allowed to freeze. Plant them in a container by October to ensure they get the chill they need. Container-planted bulbs can be planted closer to each other than they would otherwise be planted in the ground. The bulbs can touch each other, but should not touch the sides of your container. Keep freshly planted containers sheltered from wind and extremes of temperature, and keep them watered. During extreme cold, they should be moved to an unheated garage or shed. Heavy pots can be wrapped in burlap. As spring approaches, place the containers in the sun.
For a spectacular spring container display use the “double decker” planting technique. Plant a layer of tall-growing bulbs, such as tulips, 20 cm (8") deep in the container. Cover with 7.5 cm (3") of soil, then plant a layer of low-growing bulbs, such as grape hyacinths, and cover with another 12.5 cm (5") of soil and water well. (The planting depth for bulbs is generally three times their diameter.)
Great spring flowers for containers include:
- Anemone blanda -Greek windflower
- Chionodoxa -glory of the snow
- Crocus -all crocus species and Dutch crocus cultivars
- Galanthus -snowdrop
- Hyacinthus -hyacinth, all cultivars
- Iris -miniature iris, I. danfordiae and I. reticulata hybrids
- Leucojum snowflake
- Muscari -grape hyacinth, especially M. armeniacum and M. botryoides album
- Narcissus -daffodil, including strong-stemmed taller cultivars and especially, shorter-stemmed and miniature varieties
- Puschkinia, P. libanotica
- Scilla siberica (early), S. campanulata [or Hyacinthoides hispanica] (late)
For instant container colour, purchase potted bulbs in spring and pop them into your containers! This gives you the advantage of seeing how they will combine with existing spring plantings, rather than having to imagine how they will look if you are planting in the fall.