I was going to write a blog on this subject when I remembered that Susan Price had already done a piece for Garden Notes, our Master Gardener Newsletter of which she is editor in chief. So here is what she recommends. You can subscribe to Garden Notes here.
How do I select and plant flower bulbs for spring blooms? Susan Price, Master Gardener
Fall is the perfect time to be thinking about planting bulbs. Come spring, you can have a dazzling display. Tulips, Narcissus (daffodils, jonquils, etc.) and hyacinth—all true bulbs — are just some of the possibilities. For best selection, choose plump, firm bulbs that feel heavy for their size; these tend to produce big-ger and more abundant blooms. Avoid shriveled, soft or damaged bulbs.
Choose bulbs that grow well in your area and purchase as soon as they become available. If you can’t plant right away, store in a cool, dark and dry place. Bulbs can be stored in the refrigerator for up to 6 weeks but be sure to keep them away from fruits, especially apples, whose chemical reaction can damage bulbs. Local nurseries carry only the most popular bulb varieties. For a more extensive selection, purchase from reputable mail-order nurseries. Many specialize in bulbs, or even a single bulb variety.
Plant your bulbs in soil with good drainage in full sun. After bloom, dappled shade is desirable in hot inland areas. This can be easily achieved by planting underneath high branching deciduous trees. If your soil has poor drainage, amend with compost or other rich organic matter before planting. Pre-moisten the soil prior to planting for good root development. Bulbs should be planted in a hole roughly 3 times their width, with the pointed end up and their root scars down. Typically, large bulbs (2” or more) are planted about 6-8” deep and 6-8” apart; smaller-size bulbs (approximately 1”) are planted about 3-5” deep, 2-4” apart. Planting depths do vary so be sure to follow the specific planting instructions for the bulbs you’ve chosen. You can dig a trench for a planting bed or use a trowel or a bulb planter to make individual holes. Gently cover with soil, tamp down gently, and top with more soil. Top-dress with mulch to keep soil moist. Bulbs need water while they’re actively growing, so provide irrigation until winter rains kick in. Make sure to water deep enough to penetrate the root zone.
There is some debate about the need for fertilizers at planting time, especially those added to the bottom of the planting hole. The International Bulb Society offers this guidance: If you’re planting bulbs for only one year’s blooms (as annuals) there is no need to fertilize. Bulbs already carry a season’s supply of food stores. For bulbs that you intend to naturalize (“perennialize”) for years to come, you have the following options: 1) Add a good organic compost or well-rotted cow manure worked into the soil when planting, and a mulch of this material; 2) add a slow release bulb food; or 3) add a combination of bone meal and an 8-8-8 or 10-10-10 (NPK), fast-release soluble fertilizer (about one tablespoon per square foot). If you choose to add bulb formulas or other fertilizers to the planting hole, be sure to dig them into the soil, well under the root zone prior to planting as they can burn the new roots.
Plant your flowering bulbs in groups, either in small clusters or drifts, for the most eye-catching display. Lay a bulb down here and there or scatter and mix, large with small, for a spontaneous, natural look. Flowering bulbs look wonderful in containers, either by themselves or partnered with annuals. Tulips and pansies make great companions. You can plant as few as 6 or as many as 40 bulbs in a 16” wide pot for a knock-out display. You can mix and match or simply switch out pots as one group fades and another is in full bloom. To prolong the flower show, vary varieties to include early, mid- and late-season bloomers. Pay attention to plant heights as well. To maximize visual impact, place taller bloomers to the back or center and shorter ones to the front or outside.
Naturalizing bulbs such as daffodils, California native iris, Muscari (grape hyacinth), and “species” tulips, will give you many years of repeat blooms as long as you allow plants to die back naturally. This ensures that bulbs have sufficient stored nutrients to support next year’s flowers. That means not removing your flowering bulbs’ dead leaves and stems until they are completely dried out. Withered leaves can be easily hidden with strategically placed late spring and summer bloomers. The emerging foliage of annuals and perennials destined for late spring or summer bloom is enough to keep the garden in green splendor. Cat-mint, coneflowers, Veronica, daylilies and yarrow are just some of the plants that can take over the show, keeping your garden beautiful season after bulb-blooming season.