Texas has two growing seasons separated by 10 weeks of intense heat from July 1 to September 15. During this period, many perennials become dormant until the cooler days of fall, and the spring annuals are finished blooming and are going to seed. Because of this natural cycle, which includes very little rainfall, it is difficult to keep colorful annual flowers blooming and looking good in the landscape. By choosing the right annual plants and adding supplemental moisture, you can have healthy and colorful flowering plants throughout the summer.
Clear an area for your flowering plants of all weeds and garden debris. The area should be located in full sun and near a source of water, because supplemental moisture will be needed in Texas. Full sun means the sun shines on the area at least six hours a day.
Spread a 1-inch layer of well-rotted compost and the amount of granulated organic fertilizer recommended on the fertilizer container label over the cleared area. Use a hoe to work the compost and fertilizer into the top 2 to 3 inches of soil. The organic material in the compost helps the soil hold moisture. Rake the new flower bed smooth.
Plant heat-tolerant annual flowers in the flower bed with the plants that grow the tallest in the background and the shorter ones in front. If the flower bed is to be viewed from all sides, plant the taller plants in the middle and the shorter plants along the borders.
Plant on a cloudy day or in the evening so the plants can adjust for a few hours before being exposed to the Texas heat. Add water to the root systems of the plants during the planting process to ensure a good soil seal around the roots.
Add a 1-inch layer of mulch around the newly planted plants. Water every other day until the plants are established, which takes about two weeks. Annual plants typically wilt somewhat during the day and recover in the evening. If the plants do not recover in the evening, they are not getting enough water.