For The Answer
By Calvin R. Finch, PhD, SAWS Conservation Director, and Horticulturist
Week of August 29, 2005
“September Garden & Landscape Tasks”
September is an important month in our gardens and landscapes. Sometimes it does not seem like it, but average temperatures drop significantly between August and September. It is the beginning of fall and means we start our autumn gardening.
If you had problems last year with winter weeds like beggar lice, bedstraw, henbit, dandelions, rescue grass or annual blue grass – apply a pre-emergent herbicide now. Products like Amaze, Balan and Betasan will prevent the seeds from germinating if you get it down before cool weather arrives.
It is also important to be especially careful about lawn watering in the autumn. As the nights cool down, the lawn becomes very susceptible to brown patch, the fungal disease that spreads in round patterns. Those centers always seem to begin in the low wet spots on the lawn. Over watered lawns are always more likely to have the disease than drier lawns. Reduce watering overall and shift any watering to the early morning. Remember, it is against the law in San Antonio to water with sprinklers between 10:00 a.m. – 8:00 p.m. October 1 is the target date for fall lawn fertilization, but the last week in September works well. Use a “winterizer” formula.
In the vegetable garden it is late for tomatoes, but plant green beans, carrots, beets, rutabagas, and mustard with seed. Late in the month, plant your broccoli, cabbage, cauliflower, and Brussels sprout transplants. Keep the tomatoes well watered. Kelthane is the best product for controlling spider mites, but neem oil will work if you apply it two times per week under the leaves. Bt products like Thuricide, Bio Worm Control, and Dipel will kill caterpillars.
Roses resurrect themselves for the fall flush of bloom in September. Keep them sprayed for insects and fungus, and water every week that it does not rain. The tough modern roses like Belinda’s Dream or Carefree Beauty do not need the special care, like old-fashioned roses, they perform without the sprays. Water them once/month.
Autumn is the best time to observe hummingbirds. Migrating black chins, ruby throats and rufous hummingbirds move through in waves right up to December. They will linger in your yard and entertain everyone with their dogfights if you have sugar water feeders (four parts water to one part sugar by volume). Supplement the feeders by planting some firebush (full sun) and pentas (shade or sun). If they are in containers on the patio the birds will be especially easy to observe.
About the time of the first cold wave arrives, the area nurseries will stock the winter annuals. Snapdragons, stock, dianthus, petunias, calendula and alyssum can be planted after mid-month. Wait until November for pansies, cyclamen and primula.
Autumn is the best time to plant trees and shrubs. November is ideal, but right now many of the nurseries have sales on tree, shrubs and perennials. September is a good time to plant especially if the price of the plant material is right! Mulch over the root system, but do no waste your money on soil additives designed especially for planting. They are either a high phosphorous fertilizer or microorganisms. We have plenty of both in our soil and research indicates neither contributes to planting survival or growth rate under our conditions.