Treat autumn bulbs right and they’ll return the favor

Local nurseries and big box garden centers begin stocking spring-blooming bulbs in early September. In our climate zone, we “buy after Labor Day and plant before Thanksgiving.” Big-box garden centers are good sources for traditional favorites sold in large quantities, but they don’t always have a wide selection of different types of bulbs.

Local nurseries tend to stock bulb varieties that bloom well for years in our climate with its short, mild, fairly dry winters. Online bulb catalogs (several are listed here) offer the largest selections and the descriptions are very informative. When ordering bulbs online, let the shipper know that you will be prechilling hyacinth and tulip bulbs for 6 to 8 weeks (in the refrigerator vegetable drawer) and will require early shipping.

All bulbs do best in loose, well-draining soil, and our native soil is often either heavy clay or sandy. In order to create the ideal soil for bulb planting we need to amend the soil in planting beds with copious amounts of humus or compost. Since the largest bulbs (tulips, daffodils) are planted only 6 to 9 inches deep, you only need turn over and amend the top 10 inches of soil.

Bulb food or bone meal can be added to the amended soil before planting as well as in the planting holes. Place a tablespoon of bulb food or bone meal into each hole before planting the bulb. Bulb food formulations differ; the primary component is phosphorus which promotes flowering. Phosphorus is the middle number of three on the label. MiracleGro’s bulb food has a 6-8-0 formulation: Dr. Earth’s is 3-14-2 and E.B. Stone’s bone meal formulation is 1-15-0. The Dr. Earth-type formulations provide extra nitrogen and potassium and are excellent for encouraging flowering on many plants (they’re great for getting heat-stressed tomatoes and squash to set new flowers now). To promote rebloom every year, sprinkle a tablespoon of bulb food over leaf tips as they appear in early spring and again after deadheading spent flowers.

When buying, look for large, firm, plump bulbs with no green tips. Plant at a depth two times the length of the bulb: A 3-inch daffodil bulb should be planted 6 inches deep, a 1-inch sparaxis corm is planted 2 inches deep. Tulips suffer in our scorching summer heat; planting them a little deeper than two times the length protects them somewhat.

Good bulb labels will describe height, color, and flower size. They’ll also give bloom season (such as late April-early May) which we ignore since our spring flowering season arrives much earlier than the rest of the country. Do use the bloom season information as a guide to choosing several types of bulbs that will bloom consecutively throughout our short spring.

Spring-blooming bulbs are surprisingly drought-tolerant, requiring little water during our long hot summers. In fact, too much summer water causes them to rot. Plant spring-blooming bulbs in irrigation zones where other perennial drought-tolerant plants thrive.

This story was originally published September 1, 2016 at 12:25 AM with the headline "Treat autumn bulbs right and they’ll return the favor."