These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.
Success with Spring Flowering Bulbs
September 23, 1999
One of the gardening highlights of fall is choosing and planting spring-flowering
bulbs. Crocus, tulips, hyacinths, and daffodils are among the popular
choices that produce showy blooms each spring. For some gardeners, bulbs
thrive and produce great bloom every season, while for others, frustration
occurs. What are the secrets to success?
Good drainage is by far the most important factor, as few bulbs will tolerate sitting in excessively wet soil for prolonged periods of time. Improve drainage by adding organic matter to the soil prior to planting the bed this fall. Avoid low areas known to collect and hold water. Consider raised beds as a possibility in marginal areas.
Rodent and squirrels can be a problem by digging up or damaging newly planted bulbs. Cover planting areas with fine wire mesh to help prevent damage.
Most bulbs have energy stored and buds formed before they are planted, so are likely to produce the first spring after planting. For repeated quality and productive blooming, fertilize the soil prior to planting, using a complete fertilizer such as a 5-10-5 or 5-10-10 at a rate of about one pound of fertilizer per 100 (10 by 10-foot) square feet of planting area. Work this into the upper 4 to 6 inches of soil.
Bulbs fertilized will start showing improved growth and flowering the second season and beyond. Next season; apply about 2 pounds of the same fertilizer per 100 square feet when the bulbs are in bloom to the upper inch of soil.
After bulbs have bloomed the first season after planting, there are some factors that influence how likely they are to continue blooming each season. One is how long the foliage is left after blooming. Wait until leaves yellow before cutting them off to assure the plant has had time to produce food for the next season. Another problem can be deep shade that can limit growth and lead to fewer and fewer flowers each year after.
Bulbs may also get overgrown and crowded over time and require dividing.
Dig them up, divide them, and then replant. Discard bulbs showing signs
of rot. Given a choice, the best time for this would be in late spring
or early summer after the foliage has yellowed. Larger bulbs will flower
the following spring, whereas smaller bulbs may not until the second year.