Dear Neil: We have alkaline soil and heavy shade. Cotton root rot has become a real problem. What can I plant beneath our live oaks that will also be highly resistant or immune to the root rot?
A: Cotton root rot is a soil-borne fungus. It does not imply, as some will think, that soils are kept too wet. It’s just there waiting to attack susceptible plants. As for shrubs and groundcovers, the types that will handle shade and never give you a problem with the disease would include any of the dwarf hollies (dwarf yaupon, dwarf Chinese, Carissa, dwarf Burford, etc.), leatherleaf mahonias, nandinas and, in sun where you have it, junipers and abelias. I have never seen cotton root rot bother Asian jasmine, purple wintercreeper euonymus, mondograss or liriope groundcover beds. And, because you’re manipulating bed soils when you plant perennials and annuals, you should have no problems with color gardens when you work up the ground for those plantings.
Dear Neil: What would be causing my pittosporum’s leaves to wilt, one branch at a time? I notice that the bark on the affected branches has split, while the rest of the shrub remains healthy. Others have told me that it’s too much or too little water or that an animal is eating the bark or that maybe it’s not getting enough sunlight.
A: The only thing that I have ever experienced doing that to my own pittosporums was freeze damage, and that showed up much earlier than mid-summer. But it does make me wonder if it might be moisture-related. Trim out the dead area and be mindful to soak the plant deeply every five or six days in the heat of the summer. Hopefully you can stop further damage.
Dear Neil: What can I do to save this mountain laurel? It’s been in the ground for 25 years.
A: More clues would have definitely been helpful. I can’t see it well enough to know if Genista moth caterpillars stripped off all its leaves or if it has declined enough that it has dropped all its foliage. If the latter, it may have decay in the stems. It does look like it was planted a couple of inches (or more) too deeply. I don’t see any of the root flare at the soil line. I would suggest having a certified arborist look at it. He or she may want to use an air spade to open up the flare.
Dear Neil: I am forced to plant two trees of 1.5-inch diameter or greater to complete final inspection for a new ADA-compliant home on 0.157 acres next to my parents’ house in South Texas. I hate to do this in the summer, since it’s the most challenging time of the year, but it’s the rule. Which would be your suggestions, and what tips do you have on making sure they survive?
A: Some of the very best small to mid-sized trees for a smaller lot would include Little Gem southern magnolia (slower growing, but probably the best), Lacey oak (equally good), golden raintree or redbud. If Texas mountain laurel, tree-form crape myrtles or tree-form hollies would qualify, they would be excellent. My choice of large shade trees remains Shumard red oak or Chinquapin oak, but I worry that those might grow too large. Summer plantings can work fine if you protect the trees from highway winds, plant them immediately, and water them deeply with a garden hose every 2-3 days through fall. Apply paper tree wrap to oak trunks.
Dear Neil: I bought a fuchsia plant last spring and hung it in the shade, but soon parts of it started to die. How could I have prevented that? It’s gone downhill continuously.
A: The optimum conditions for fuchsias are full, bright sun and daytime highs in the 60s. As such, Texas is not their favorite places to spend late spring and summer. Honestly, plant vendors ought to point all that out when you buy one. It’s virtually impossible to keep one alive through a Texas summer. In fact, I’d be willing to delete the word “virtually.”
Dear Neil: My daughter gave me a plum tree three years ago. When is the best time to prune a plum, and what is their life expectancy?
A: You begin pruning plum trees the day that you plant them. Prune them to 22 to 24 inches and begin to train their horizontal, “scaffold” branches on which the fruit will be carried. Each winter thereafter you prune to create horizontal branching and to remove strongly vertical shoots. The tree should grow to be 8 or 9 feet tall and 15 or 16 feet wide. That way the sunlight will reach all of the ripening fruit, and it can also be harvested from the ground. If peach tree borers leave your plum alone, you can expect it to live 10 to 15 years, perhaps 20.
Dear Neil: I’m not sure if this is take all root rot or not. We have lots of trees and shade. We are getting the trees trimmed later this month or in August. Our yard looks sick, while others are lush and lovely. What can you suggest?
A: I don’t want to suggest anything until we’re a lot more certain of the cause. In my many years of getting variations of this same question, most of the time it’s been associated with excessive shade. But pruning usually doesn’t help that for very long because the trees grow right back. In my own landscape I changed over to shade-tolerant groundcovers, but to go into all that detail would be to write chapters, and as mentioned, I don’t want to do that until we are more certain, especially without the help of a photo. Please look closely at your lawn. Is the grass worst in the heaviest of the shady areas?
If you’d like Neil Sperry’s help with a plant question, drop him a note in care of The Eagle, P.O. Box 3000, Bryan, Texas 77805. Or email him at email@example.com.