Planting spring bulbs
Autumn is the time to plant spring-flowering bulbs: daffodils, narcissus, jonquils, crocuses, hyacinths, tulips, and bulb irises.
Spring-blooming bulbs should be planted in the fall in order to get good root growth before the ground gets cold in winter. Plant spring bulbs any time within two or three weeks after the leaves fall. (Almost all tulips need an extended cold period for best growth and bloom; here in Sonoma Valley put bulbs in the refrigerator for six weeks before planting.)
Plant bulbs about two to three times as deep as they are tall. Narcissuses, daffodils, and jonquils should be planted 3 to 4 inches deep to the tops of the bulbs. Hyacinths should be set 3 to 5 inches deep. Tulips should be set 5 to 6 inches deep. Space bulbs at least 6 to 8 inches apart, or three times their width for smaller bulbs. Where bulbs are planted in grass or sod, they can be set slightly shallower because they will be more protected than if they were set in open ground.
Bulbs prefer a sunny location, though they will bloom in light shade. Flowers usually face the sun so keep this in mind when selecting the location for bulb beds.
While most bulbs do well in any kind of soil, for the best success, prepare bulb planting beds by turning the soil to a spade’s depth – about 12 inches – and adding well-rotted compost and aged, not fresh, steer manure. Bone meal, which is rich in phosphorus and supports root growth and blooms, can be spread lightly across the planting bed or added to planting holes. Where the soil is very poor, bulbs will soon peter out, the blossoms becoming fewer and smaller each year.
No matter how rich the soil, good drainage is essential for flowering bulbs. The roots of most bulbs will stand an abundance of moisture below the bulb – you can force a bulb to flower in plain water as long as the bulb itself is held above the water – but wet bulbs will rot.
A bulb bed is best rounded up before planting. Be sure the planting bed is high enough that no surface water can collect on it from winter rain. In heavy soil, which naturally holds a great deal of water in fall or spring, the bed should be raised a foot or so above the general garden level.
Once planted, most bulbs become naturalized and will reproduce and bloom indefinitely without further attention. However, for optimal growth and show, take up bulb clumps every second or third year just before the foliage dies down, then divide and replant them so they are less crowded.
The quickest method of planting bulbs is with a blunt dibble, marked plainly from two to ten inches, so that you can tell just how deep you are making the holes. Have some coarse sand handy when planting bulbs. Put a handful of sand at the bottom of each hole; this protects the bulb, insures good drainage directly under it, and prevents it from resting over an empty air space left by the point of the dibble.
When planting full beds of bulbs, first turn the soil across the whole bed to several inches deep and rake it even, then place the bulbs or wooden markers across the bed to be sure you are evenly spacing the planting holes. Put the bulbs in place and cover. When several sorts of bulbs are to be used in the same bed, planted at different depths, the same method may be used, starting with those to be planted deepest and covering a layer at a time.
Usually fall and winter rains provide all the moisture spring bulbs require. But if the fall and winter are dry and bulb leaves begin to yellow before the bloom time ends then be sure to give planting beds plenty of moisture.
If you are new to spring bulb planting, here are some of the best known and best performing spring bulbs:
Trumpet daffodils – one flower to each stem: yellow ‘King Alfred’ and ‘Dutch Master’; pure white ‘Mount Hood.’
Narcissus – each stem bears four to eight fragrant, short cup flowers: ‘Paper White’ is pure white; ‘Grand Soleil d’Or’ is yellow with an orange cup.
Tulips – there are many tulips to choose from, early-, mid-, and late-season. In mild climates, mid- and late-season varieties perform best. Darwin hybrids are bright scarlet-orange to red and also pink, yellow and white. Rembrandt tulips have streaks of colors. Parrot tulips are fringed and ruffled and feathery looking. Double tulips look much like peonies.
Steve Albert is the author of The Kitchen Garden Grower’s Guide available at Amazon.com. He teaches in the landscape design program at the U.C. Berkeley Extension. He lives in Oakmont.