Iowa State University
INDEX A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Planting Depth and Spacing of Spring-flowering Bulbs

This article was published originally on 9/13/2002

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.

Year of Publication: 
2002
Issue: 
IC-487(22) -- September 13, 2002