Q. We had a cedar elm tree die of hypoxylon canker. The arborist involved made it sound like that there was nothing to do to protect the other trees in the vicinity from becoming infected. That cannot be right can it?
A. I am afraid that is pretty much correct. The disease infects trees that are growing in poor conditions and are stressed. A disease organism exists, but infection is related to the lack of water and good growing conditions rather than any kind of spread of the organism from one tree to another. A new irrigation program may help to prevent more trees in the vicinity developing the disease and dying, but there is no guarantee.
Q. We have built a new raised bed and want to grow a fall tomato crop. The soil is an equal mix of compost, soil and sand. We have learned in the past that such a soil mix is great to work with, but requires to be enriched with nutrients to grow a good crop. What is your recommendation to prepare it for fall tomatoes?
A. I recommend that you apply 10 cups of slow release lawn fertilizer for every 100 square feet of new bed. The 19-5-9 mix works well.
Q. We have brown patches in our zoysia lawn. Does it work to replace the dead areas with patches of fresh sod?
A. Is the sod dormant or dead? Zoysia grass will turn brown if it does not receive enough water, but it will recover when the rains or irrigation and cool temperatures return. To test the brown areas, select two or three patches and water them generously every other day for a week. The test areas will green up if the grass is just dormant. You will not have to waste money and all that hard work on replacing the brown patches.
Q. Is it true that we can buy esperanza and poinciana in full bloom at the nursery and plant them immediately in the ground without eliminating the bloom?
A. Yes, the plants can be slipped out of the container without disturbing the root ball and carefully placed in the pre-dug hole in full sun. Dig the hole as deep as the plant is in the container and two to three times as wide. Run water into the hole until it fills up, and then cover the roots with 3 inches of mulch.
Q. We are new in the effort to make good habitat for Monarch butterflies. We have planted 10 tropical milkweeds for Monarch egg-laying sites, but notice that the Queen butterflies are laying their eggs with the caterpillars eating the foliage. Will there be any milkweed left this fall when the Monarchs return to San Antonio? Should we intervene?
A. The Monarch natural history is complex! I do not recommend that you intervene. It is most desirable if the Monarchs that visit San Antonio in the fall just use the milkweeds for nectar to continue the migration trip, rather than lay any eggs. The same individuals that travel through to the wintering ground this fall should return in the spring to lay eggs.