Yes, it is that time of year in Texas! The heat has arrived and all the beneficial rains have stopped. When I am on site walking properties, I not only feel the heat, but I can see the stress the heat is causing plant materials. Monitor your plants closely and if you observe wilting or yellowing, and your soil is dry, water!
If you are watering and your soil is wet, but you observe yellow or browning leaves, this could be due to the plant not keeping up with water loss from the leaves and the plant is adjusting to the heat by self-pruning leaves to conserve water loss. This is not a bad thing to see leaves falling off plants. The remaining leaves are what the plant roots can sustain in the extreme hot weather. Your job in this process is just to make certain the plants receive adequate moisture.
If your turf is browning and soil is dry and cracking, probe to a depth of 6 inches and if dry at that depth, add water. If you are applying adequate moisture and soil is moist at that depth, the brown turf could be due to heat stress. During excessive heat, turf will go into dormancy for protection. Fortunately, your turf can tolerate much drought and as soon as adequate moisture is applied or the extreme heat breaks, the turf will start growing again and green up. Turf likes water and fertilizer so make sure you are doing both of these things if you want to keep your turf green.
Browning turf can also be caused by grubworms and sod armyworms. If grubworms are present, the brown turf will lift right out of the ground and you will see white grubworms. If armyworms are present, you will see a hoard of worms eating your turf. If present, treat either of these worms with a granular turf insecticide.
This is Texas so the hot weather is here to stay for a while. Assist your plants with the water needed to survive this heat.