Planting Depth and Spacing of Spring-flowering Bulbs

The array of spring-flowering bulbs includes tulips, daffodils, crocuses, hyacinths, snowdrops, and flowering onions. By planting a variety of spring-flowering bulbs, gardeners can enjoy blooming plants from late March to mid-June.

For best selection, visit your local garden center early. Select large, firm bulbs. Avoid soft or blemished bulbs. Store purchased bulbs in a cool, dry location until they can be planted in the fall. October is the ideal time to plant spring-flowering bulbs. To achieve the greatest visual impact, plant spring-flowering bulbs in clusters or drifts. When planting tulips or daffodils, plant 10 or more bulbs of the same variety in a cluster. Smaller growing bulbs, such as Siberian squill, should be planted in drifts of 50 or more. The flowering list provides planting depth and spacing of various spring-flowering bulbs.

Bulb Depth* Spacing
Allium spp. (Ornamental Onion)
large bulbs (A. giganteum and others) 6 inches 12 to 18 inches
small bulbs (A. moly, A. unifolium, etc.) 3 to 5 inches 6 to 8 inches
Camassia spp. (Quamash) 4 inches 4 inches
Chionodoxa luciliae (Glory-of-the-Snow) 3 to 4 inches 3 inches
Crocus spp. (Crocus) 3 to 4 inches 3 inches
Fritillaria spp. (Fritillaria)
Fritillaria imperialis (Crown Imperial) 6 to 8 inches 12 to 18 inches
F. meleagris other small flowering types 3 to 4 inches 4 inches
Galanthus nivalis (Common Snowdrop) 3 to 4 inches 3 inches
Hyacinthoides hispanica (Spanish Bluebell) 4 inches 4 to 6 inches
Hyacinthus orientalis (Hyacinth) 6 inches 6 to 8 inches
Leucojum vernum (Spring Snowflake) 3 to 4 inches 3 to 4 inches
Muscari armeniacum (Grape Hyacinth) 3 to 4 inches 3 to 4 inches
Narcissus spp. (Daffodil)
Trumpet, large-cupped, etc. 6 to 8 inches 6 to 8 inches
Miniature and other small bulbs 3 to 5 inches 4 to 6 inches
Puschkinia scilloides (Striped Squill) 3 to 4 inches 3 inches
Scilla siberica (Siberian Squill) 3 to 4 inches 3 inches
Tulipa spp. (Tulip)
Darwin hybrid tulips, triumph tulips, etc. 6 to 8 inches 4 to 6 inches
Species or botanical tulips 3 to 5 inches 3 to 4 inches

* Planting depth is measured from the base of the bulb to the soil surface.

This article originally appeared in the September 13, 2002 issue, p. 118.

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