Calvin R. Finch, Ph.D., Conservation
Manager, San Antonio Water System,
Q. Tell me something about the Mexican white oak. I am afraid of oak wilt and have heard that this tree is a good option.
A. According to Paul Cox of the San Antonio Botanical Gardens, Mexican white oak entered the nursery trade in our area in the 80s. It is native to Northern Mexico and Texas near Del Rio. The tree is an outstanding landscape tree. It grows as fast as Texas red oak, looks like a live oak, and appears to be oak wilt resistant. Monterrey oak is a trademark name for Mexican white oak. Mexican white oak is a good xeriscape plant.
Q. Is it time to plant tomatoes?
A. Yes, plant a determinate variety such as Sun Master, Merced, Heat Wave, Surefire, Celebrity, Carnival, Bingo, or Whirlaway. Mulch over the root system to help prevent blossom end rot.
Q. We saw our first hummingbirds. They were on our Salvia greggii. What is the sugar water mix? Do we need to boil or use coloring in the water?
A. Mix four parts water to one part sugar by volume. Boiling may help dissolve the sugar in the water but is not necessary. Store excess sugar water in a recycled plastic milk jug in the refrigerator. Put fresh solution in the feeder each week. Place the used sugar water in a flat container for the butterflies.
We use red food coloring but it does not appear to be necessary.
Q. The bluebonnets are so small. Will they increase in size with the rains? How long do we have to leave the old plants to encourage reseeding?
A. Yes, if you received one or two good rains in March, expect the bluebonnets to grow to normal size sometime before mid-April. It is best to leave the old plants until they brown and the seeds are distributed naturally. If you must rush the process, leave the plants until the pods are full size and show some color change (straw color). At that point you can mow. It also works to pull the plants and place them in new locations where you want to seed new plants. Remember, wildflowers will not reseed in sod or mulched soil. The seed must reach soil and be exposed to light.