Fall is the perfect time for planting spring flowering bulbs (tulips, crocus, hyacinths, daffodils and others) and normally we are cool enough by mid-October to plant. The general rule of thumb is to plant these bulbs between October 15th and December 15th. So don't wait to long because these bulbs need a minimum of 12 weeks of under 45 degrees to bloom.
The key to success with bulbs is understanding what they are and how they grow. The bulb is actually a self-contained plant, the flower bud is already formed and just waiting for a dormant winter treatment, and the sides of the bulb are modified leaves. Tulips must totally regenerate a new bulb after flowering. To improve the bulbs ability to regenerate itself after flowering, the spent flower stalk needs to be removed, the plants fertilized with bulb food or a bloom booster fertilizer, and the foliage needs to remain green and growing as long as possible. These bulbs come from Holland in northern Europe, on about the same latitude as southern Canada. They grow in a much cooler climate and in very porous and sandy soil. With St. Louis turning hot in May, and our heavy clay soils, the bulb has a hard time regenerating. There are some things that you can do to improve your chances for multiple years of returning flowers:
1. Really improve the soil prior to planting, adding plenty of organic matter (peat moss, compost, and manure) as well as sand or turface to improve drainage.
2. Feed the bulbs in the fall when planting, again in early spring prior to blooming, and once more right after blooming.
3. Try to plant other annuals and perennials in between bulbs, and not directly on top. Its common to lose more bulbs by drowning them when watering other plants than from bulbs drying out.
4. Again leave the foliage as long as it remains green and growing until it turns yellow or brown. Once the foliage is brown, it can be removed.
5. Plant your bulbs in clusters and groups to have more impact and interest! Bulbs come in all colors and sizes with bloom times from late February to late May. They can grow in almost any light exposure. Using early flowering bulbs under trees will work because they will bloom before the trees leaf out and then the shade will keep the foliage growing longer.