I live in western Colorado and the soil is very heavy and composed
of clay. How much compost is needed before I plant my bulbs? Is cow
manure ok?
In My Garden Blog
Western Mountains and High Plains
October 22, 2009
By
John Cretti,
Denver, CO
These colorful daffodils will welcome spring if bulbs are planted now!
Let's Plant Spring
With autumn upon us, landscapes and gardens are displaying dry foliage and ripening golden winter squash, bright orange pumpkins, and colorful foliage in shrubs and trees. It's a perfect time of year to plant some bulbs for spring blooms.
With a little planning and work this fall, you can have crocuses peeking through melting snow in February, drifts of golden daffodils, and flower beds filled with radiant tulips and hyacinths until May. These are just a few of the fall-planted bulbs that cast their magic spell in spring.
Typical bulb-planting charts are for well-drained soils, which are not common in our region. Most bulbs will do best and survive the longest in a sandy loam or clay loam. Soils with high clay content are best amended with compost, sphagnum peat moss, perlite, or scoria (crushed volcanic rock) to improve soil texture. Sandy and rocky soils need organic amendments to help retain moisture and nutrients.
To plant your pretty visions of spring, you have from now through mid-December, while the soil remains unfrozen but soil temperatures have cooled down. Once planted and watered in, bulbs will begin to develop a strong, healthy root system before the ground freezes.
Spring-flowering bulbs are among the most versatile perennials when planted properly. They can be planted in perennial flower beds, around shrub borders, along pathways, and in separate flower beds or naturalized in lawns. Some favorite plantings include crocuses, muscaris, daffodils, and selected types of tulips in casual drifts around the landscape and along garden pathways. This is a landscape technique called "naturalizing" since the plants grow and bloom as if they were placed there by nature's hand.
The Right Location
In our higher elevations, most spring-flowering bulbs perform best with morning sun and afternoon shade. Flowers will last much longer in such a setting. You should also provide protection from drying winds, which often are responsible for scorched flower petals. The early-blooming bulbs including snowdrops (Galanthus spp) and winter aconite (Eranthis spp) will do beautifully beneath trees and shrubs because the canopy of shade will not unfurl until after the bulb blossoms have faded.
Mass Plantings
Many gardeners like to dig a hole for each bulb with a bulb planter, but it's more effective to plant bulbs in a group or mass planting. The technique is to make a hole that is big enough to accommodate all the bulbs to go in a given area. Apply compost at the bottom of the excavated bed and incorporate it a bit deeper, where the roots will grow. After the bulbs are positioned in the planting site, cover them with amended soil and water in thoroughly.
Water and Mulch Well
Since we often lack adequate natural precipitation during the fall, it's important to water new bulb beds periodically throughout the season to ensure good root growth. Check the soil with a hand trowel; if it's beginning to dry out, water as necessary until the soil freezes up solid. Depending upon the unpredictable weather in our region, fall and early winter watering may be necessary every 4 to 5 weeks, depending upon the flower bed's exposure.
After the first hard frosts, in late fall or early winter depending on your location, apply a layer of organic mulch to the bulb bed. Two to 3 inches of shredded cedar mulch, aspen mulch, dried grass clippings (those not treated with herbicides), or shredded leaves will help to retain moisture, reduce weed growth, and prevent soil heaving.
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We welcome your questions and comments about this column. If you have gardening questions unrelated to the column, please ask them on our message boards.
Joe
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John C
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It is a good idea to add about one-third by volume of compost to the
planting area. A homemade compost is best and work into the backfill
soil and at the bottom of the planting sites. This improves drainage
and helps with nutrient availability. Manure is OK if it is
well-aged or composted. Do not use if it is fresh. You might find
that adding some perlite will improve the structure of the soil too,
and prevent it from compacting.
John C
You can plant bulbs after the snow has melted and soaked in. As long
as the ground remains unfrozen, go for it. They will root and bloom
next spring.