Bulbs, rhizomes and corms all have different planting requirements, but with a little TLC you can get them into the ground in winter and appreciate their color and beauty come spring. For those of us who greatly miss tulip time in the Midwest, there are opportunities for a South Texas spring bouquet of tulips, daffodils and irises. But you must be selective to be successful.
First, a short review about bulbs. There are three types: bulbs, rhizomes and corms.
Bulbs are oval or egg-shaped root structures that when cut open appear to have layers upon layers. Tulips and daffodils are examples.
Rhizomes are stems that grow horizontally, just below the soil surface. Gingers and iris have rhizomes.
Corms can be bulb shaped, but are frequently in the shape of a large bagel. Gladiolus and crocuses are grown from corms.
Tulips: There is only one tulip that will grow year after year in South Texas and that is the Persian byzantine or Clusium tulip (Tulipa clusiana). Traditional Dutch bulbs may be used, but they’re really only good for one year, so dig up and discard in June.
Daffodils: Narcissus species will provide consistent color year after year if planted in the right place, such as in garden beds with exposure to sun in spring and shade in the summer. Choose the older varieties, which are rugged and remain active for years.
Iris: Tough, drought-tolerant, and deer-resistant, iris can frequently be found in old cemeteries throughout Texas.
Gladiolus is the tallest of the bulbs. It’s best planted at varying times during winter and spring to ensure flowering throughout the year.
For all bulbous plants, create a special garden bed or use a large, shallow container for best results. Use a sandy loam soil with small amounts of organic matter like sphagnum moss and an inert material like perlite or decomposed granite. (Tip: Add approximately ½ cup of coffee grounds per 1 cubic foot of soil to acidify the soil.) Plant the root structure just below the soil surface — not too shallow, not too deep, but just right.
Water consistently, but not to excess. In other words, don’t rely on an automatic irrigation system. Water once every other week in addition to natural rainfall and once a week if no rainfall occurs. Remove dead foliage, but don’t cut the plant back until September. Divide the beds every other year and fertilize in fall of the off year with any 3-1-2 ratio lawn fertilizer.
By Mark A. Peterson, a conservation project coordinator for San Antonio Water System. With over 30 years of experience as an urban forester and arborist, Mark is probably the only person you know who actually prunes trees for fun. When not expounding on the benefits of trees and limited lawns, you’re likely to find him hiking San Antonio’s wilderness parks or expounding on the virtues of geography and history to his friends.