Temperatures at night will become cooler as the month progresses encouraging the germination of the winter weeds. To reduce the quantity of weeds such as bedstraw, dandelions, thistle, henbit, beggars’ lice and chickweed in the lawn apply a preemergent such as Amaze, XL, or Dimension early in the month.
The fall tomatoes will also respond to the moderating temperatures. Expect the leaves to expand in area and number. They will start setting fruit.
It is also time to plant winter vegetables such as broccoli, cabbage, radish, turnips, rutabagas, mustard greens, Brussels sprouts, beets and cauliflower. Prepare the soil by applying 2 inches of compost and 10 cups of slow-release lawn fertilizer for every 100 sq. ft. of bed. The greens and cole crops will attract cabbage loopers so have the Bt ready to apply as soon as any damage is noticed. Bt is an organic control derived from a bacteria that kills caterpillars when it is consumed as they feed on foliage. Follow label instructions.
In the flower garden the hot weather annuals such as zinnias, cosmos, and vinca, will respond to the more moderate temps and you can expect another 3 months of bloom. The begonias may even make it through the winter. Wait until next month to plant cyclamen and primula as cool weather shade plants. You can also plant the cool weather annuals such as snapdragons, stocks, dianthus, alyssum and calendula in the sun.
How you use the available space in the flower garden is an important decision in the fall. The zinnias are the best nectar plant among the annual flowers, and they are a favorite of the seed eating birds but if you delay planting the cool weather annuals you lose out on the best of the early winter bloom period. Good luck on your decisions!
The Monarch butterflies will be in San Antonio over the next few months joining the Queens, Swallowtails, Gulf Fritillaries, and other species on your nectar plants. In the fall the mistflower, milkweed, porterweed, pentas and zinnias are joined by the salvias, lantanas, duranta, fall asters, mint marigold, and Mexican flame vine as favorite nectar sources. The hummingbirds will seek nectar on most of the same species and also seek out firebush and cape honeysuckle.
Late in September or early in October fertilize the lawn with “winterizer” lawn fertilizer with a 3-1-2 nutrient ratio such as 18-6-12.
If you did not spread your wildflower seeds in August, do it in September. In addition to your favorite coreopsis, poppies, bluebonnets, paintbrush, and Mexican hat obtain and plant some blue curl seed. The attractive blue flowers stay in bloom over a long period and are an important nectar source that fills a gap before the mistflower, zinnias and milkweed begin blooming.