My Blue Squill Did Not Bloom This Year

Wrong Hardiness Range

• Blue squill, also called Siberian squill, is native to Eurasia and is very cold-hardy. Blue squill is hardy throughout U.S. Department of Agriculture Zones 2 or 3 through 8. If you live outside those plant zones, you will have trouble with squill lasting in your garden. In colder zones, the bulb won't recover from winter cold. In zones warmer than 8, the lack of a winter cold dormant period causes the bulb to decline. First the bulb stops blooming, then eventually the bulb dies out completely.

Foliage Not Matured

• Each year, bulbs build up their strength for the next year's flower display by producing food with photosynthesis through their leaves. Cutting the leaves while they're still green or tying them into bundles inhibits the amount of photosynthesis and weakens the bulb, making it less likely that the bulb will flower the next year. Always let foliage wither and brown on its own before mowing it down.

Improper Planting

• Site blue squill bulbs where they receive plenty of spring sunshine, such as in a lawn or under deciduous trees. Evergreen trees and shrubs cast too much shade for Scillas, and they can't replenish themselves adequately. Plant the bulbs in well-drained soil, because wet soil encourages rot and bulb death. Plant blue squill bulbs 3 inches deep and 4 to 6 inches apart.

Overcrowding

• One of blue squill's most charming habits is its ability to naturalize quickly, but that same tendency leads to overcrowding of the bulbs. If your squills have been blooming well for years but the display has declined to only a few blooms, it's time to renew the planting bed. Mark their location, and in the fall, dig up the bulbs with a garden fork. Amend the soil with organic matter such as compost or well-rotted manure, then replant the bulbs at the proper spacing and depth. Discard any bulbs that were damaged during digging or that are soft or discolored.

Insects and Animals

• Scilla bulbs are rarely bothered by rodents such as voles or chipmunks or by animals such as deer or rabbits. However, hungry deer or rabbits will graze on blue squill foliage and blooms if tastier food is unavailable. You'll see signs of animal grazing, such as chewed down foliage or flower stems that look as if the blooms have been broken off, as well as tracks in the dirt. Insect grubs occasionally bother scillas, as well. Dig around in the dirt near the bulbs and look for the grubs, or bring up a few bulbs and examine them for signs of grub damage, such as tunnelling. Consult your local garden center or cooperative extension service for advice if grubs are found.