Released: October 22, 2001

Spring Flowering Bulbs Have Planting-Bed Needs

MANHATTAN, Kan. – Halloween is the traditional deadline for planting spring-flowering crocus, daffodil, hyacinth, tulip, snowdrop and other hardy bulbs in the central High Plains.

The reason for the fall planting season is also why High Plains gardens beat those in the South hands-down on spring bulb displays. To bloom from year to year, hardy bulbs need to establish roots by late fall and then go through an extended chilling period, said Ward Upham, Kansas State University horticulturist.

"No matter their bulb size or blooming time, however, all hardy bulbs also have a few other needs in common," he warned.

In general, for example, these spring bloomers do best with the following:

* Full to partial sun during their growing season. (Bulbs can even do well at the foot of a large deciduous tree, if their foliage will emerge, develop and "ripen" before the tree leafs out.)

* Sandy loam or improved soil with a pH between 6.0 and 7.0. Heavy clay and very sandy soils will need to be mixed 2-to-1 or 1-to-1 with an organic material such as peat moss, compost or aged bark.

* Soil with good drainage and aeration – which typically means preparing the planting area by tilling 12 inches deep.

* Adequate soil nutrients

"For gardeners who like specific recipes, I usually suggest incorporating a complete fertilizer, such as a 5-10-5, at the rate of 3 pounds per 100 square feet or a 9-13-7 or 11-15-11 at the rate of 1.5 pounds per 100 square feet. Also, add a 4-inch layer of organic material. Then mix fertilizer and organic material into the top 8 inches of garden soil," Upham said.

Proper planting depth varies by size of bulb. In this case, depth is determined by the distance from the bottom of the bulb to the top of the soil (surface).

"As a rule of thumb, you plant bulbs two to three times deeper than the bulbs themselves are wide," the horticulturist said. "Typically that means about 6 inches deep for tulips and hyacinths, but 6 to 8 inches deep for daffodils and perhaps 2 to 3 inches for little crocus corms."

The correct spacing between bulbs also varies, but averages 4 to 6 inches apart for large bulbs and 1 to 2 inches for small ones.

"Just remember that all hardy bulbs look best if planted together in clumps or scattered as if they were growing and spreading in the wild. Nothing looks sadder than a single tulip, braving spring’s weather all alone," Upham said.

Hardy bulbs will not produce any top growth after planting in fall. They’ll devote all their energy to developing roots before winter.

"So, you just have to remember they’re there and will need enough watering to keep the ground moist, but not wet, until it freezes," the horticulturist said. "While planting, I’ll even replace half the soil, water, replace the rest of the soil and then water again. This helps provide good soil-bulb contact, as well as makes sure the plants have enough moisture to get off to a good start."

Newly planted small bulbs, in particular, can benefit from mulching after the soil freezes. Without such protection, winter’s alternate freezing and thawing can heave little bulbs from the ground.

Upham coordinates the horticulture part of K-State Research and Extension’s statewide diagnosis service for plant programs. The service includes every Kansas county Extension office, as well as campus-based faculty in plant pathology, entomology and biology.

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Box: 
Spring Bloom Extenders

VERY EARLY:

winter aconite (eranthis)

snowdrop (galanthus)

bulbous iris (Iris reticulata and I. danfordiae)

crocus

hoop-petticoat daffodil and hybrids (Narcissus bulbocodium and N. cyclamineus)

Siberian squill (Scilla siberica)

glory-of-the-snow (Chionodoxa luciliae)

Grecian windflower (Anemone blanda)

"waterlily" tulip (Tulipa kaufmanniana and hybrids)

fosterana tulip

LATE:

Dutch iris hybrids (Iris xiphium)

wood hyacinth (Endymion hispanicus, sometimes listed as Hyacinthoides hispanicus or Scilla campanulata)

summer snowflake (Leucojum aestivum)

star-of-Bethlehem (Ornithogalum umbellatum)

crown-imperial tulip (Fritillaria imperialis)

dog-tooth violet (erythronium)

hardy cyclamen (Cyclamen repandum)

violet wood sorrel (Oxalis violacea)

allium varieties

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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by:
Kathleen Ward, Communications Specialist
kward@oznet.ksu.edu
K-State Research& Extension News