Saturday, September 1, 2001
Submitted by Calvin Finch, Ph.D., Director of Conservation, SAWS, and Horticulturist
SPRING BULBS

 

By most accounts, tulips are the most popular flower after roses. Massed beds of red, yellow, pink, white or bi-colored blooms in early spring are spectacular.

 

Tulips will produce spring blooms in San Antonio but they will not replenish themselves, survive the summer, and rebloom next year. We need to treat tulips as an annual. Plant the bulbs in November or December for flowers in February.

 

There are several practices that are essential if you are going to be successful with tulips:

 

·        For tulips to grow they must experience a chill period. In the North this chill period is accomplished trough the cold winter weather. Here in San Antonio chill is achieved by placing the bulbs in the refrigerator for six to eight weeks. Put them in a brown paper sack or leave them in their box and place the bulbs in the vegetable crisper, definitely not the freezer.

 

·        Squirrels love tulip bulbs. Protect them after they are planted by laying half- inch chicken wire or hardware cloth over the bed. The pesky mammals do not like digging in wire. At the first sign of tulip leaves remove the mesh. If you plant the tulips four inches or deeper, one inch chicken wire works and you do not have to remove it. The tulips grow through the holes in the wire. Squirrels lose interest in tulip bulbs after the leaves emerge. Then the deer take over!

 

Here are some hints that will help you be successful with tulips?

 

·        The books say to plant tulips six or more inches deep. When they are used as annuals, it is not necessary to plant them that deep. Deep planting puts the bulbs in a soil zone that is cool and moist. If they are used as annuals, it is not necessary that tulips be planted any deeper than three or four inches.

 

·        Another recommendation in most accounts of tulip culture is the use of bone meal. Bulbs utilize phosphorous and calcium which bone meal provides but our soil is loaded with the materials. Bone meal is not recommended for South Texas. Bulbs used as annuals also do not need to store nutrients.

 

·        The planting site can be in full sun but morning sun with afternoon shade seems to be better in a hot climate where the bulbs are used as an annual. The length of bloom period in the spring is determined by the temperatures. The tulip blooms fade quickly when the spring is hot and dry.

 

·        Raised beds watered with drip irrigation are ideal planting sites. Drainage is a factor even with bulbs used over a short season as annuals. Tulip bulbs rot in heavy soils that do not dry out.

 

·        There is a question of whether tulips used as annuals require any fertilization. The energy for the bloom comes mainly from the bulb. Fertilization is important if the bulbs will overwinter and rebloom; but, since we rarely get enough cold weather in San Antonio for that to happen, fertilization is a minor influence. I apply 3 lbs. of slow release lawn fertilizer over 100 sq. ft. of bed at the time of soil preparation or planting.

 

·        Two inches of a fine mulch like leaves or compost will help keep the soil cool and moist while it reduces weed germination.

 

·        Treat hyacinths just as you would tulips. Several varieties of daffodils and alliums, however, do not need the chill period and will naturalize.

 

       You can order your bulbs now from your favorite nursery or one of the many catalog nurseries. Reject any wounded or moldy bulbs. It is not a problem if your bulbs are in the refrigerator for more than eight weeks. So, after inspection, refrigerate them until November.