GARDENER'S MAILBAG: Did my Italian cypress trees experience freeze damage?

By Neil Sperry
Special to the Herald Democrat

Dear Neil: I believe these are three Italian cypress trees. They were doing great until the big freeze, but gradually they have gone downhill. Was the cold responsible? Will they come back?

Italian Cypress Frozen

You are correct on your identification, and you are also correct on the diagnosis of freeze damage. Italian cypress trees are normally dependable in the southern half of Texas, but this February’s cold has killed plants over big parts of the state. Curiously, it wasn’t obvious immediately. It started showing up several weeks after the thaw, and it’s still getting worse. You’re going to need to think about replacing these. I’m sorry for the bad news.

Dear Neil: My tomato plants’ blooms are all falling off without setting fruit. What causes this, and what can I do to correct it?

Tomato blooms look like they've been cut off

This is a very common question with tomatoes at this time of year. One of the most common causes is poor variety selection. Large-fruiting types, including Big Boy and Beefsteak, will not set fruit when temperatures begin to get hot (or when it’s cool at night). They were bred for northern summer gardens and certainly not for Texas. We need to stick with small and mid-sized types. Also, plants that do not receive enough mechanical agitation by the wind won’t get pollinated. Tomatoes are not pollinated by bees. Their pollen sheds within the individual flowers, and wind is critical to causing the plants to shake and shed their pollen. If your plants are growing against a fence or wall, strange as it may seem, it might help if you thumped each flower cluster every couple of days. And there’s also the chance that prolonged cloudy, cool weather might have contributed.

Dear Neil: I know you have been warning us not to let anyone cut down oaks that have been slow to leaf out this spring. Does that warning continue now as we head into June?

Absolutely! Some of the state’s most respected arborists, nursery professionals, Extension horticulturists and, most notable of all, veteran foresters with the Texas A&M Forest Service, continue to tell us that a big percentage of oaks are producing new growth at their own pace, some rather rapidly and others painfully slowly. But they keep telling us there is no reason to hurry. We all are seeing examples of leftover damage to trees from the cold, so no one is going to think poorly of you because you have a tree that is sluggish. Oaks, especially, have survived here for centuries, and almost all will survive this bad experience, too. (I know you’ve seen this answer before here, but I’m being asked this repeatedly everywhere I go. This week’s emails had five consecutive questions on this same topic. Our oaks are worth fighting for.)

Dear Neil: I’ve attached a photo of my 16-year-old Italian stone pines. They are 40 feet tall, and I had scheduled to have them taken out due to damage from the February cold. However, before the company arrived I saw new green growth coming out from the tips of the branches. Is it enough to support large trees like this?

Frozen Italian Stone Pines

Judging from the photo, probably not, but again, there is no harm in waiting. Granted, they’re unattractive, but if you want to wait another couple of months to monitor if more new growth is produced, you’ll have a better idea.

Dear Neil: About five years ago I planted three rose bushes. Almost immediately they became infested with black spot fungus, I suspect from the nursery. I’d like to pull them out and try again. How long will the ground remain infested with black spot before it is healed?

Black spot is almost omnipresent in our environment. I certainly wouldn’t blame the nursery. We all have it on most of our roses in spring and fall when it’s cool and humid in Texas. If you decide to replace your plants, take a look at the varieties listed by Texas A&M at their EarthKind® Roses page. These are a couple of dozen varieties of roses that have been thoroughly tested in many gardens across America for their proven resistance to black spot. Be sure, too, that you’re not fighting the much more serious (and fatal) rose rosette virus. Its symptoms are very different from black spot. Rosette causes distorted growth, buds that don’t open properly, extreme thorniness and very strong “bull” canes. Black spot causes only yellowed leaves with dark brown or black spots on the leaves.

Dear Neil: We lost our privacy plants between our house and our (very nice) neighbors’ two-story house. They now can peer directly into our windows. I want to plant Nellie R. Stevens hollies, but was advised to plant them 5 feet apart. If I’m going to want them to grow to 18 to 20 feet tall, will that be enough room?

Great observation! No. They need to be approximately two-thirds as far apart as their heights will be. That means 12 to 13 feet apart. If you plant them much closer than that they will crowd into one another and kill their bottom branches. They’re a great choice for what you want, but you have to give them adequate space to fill out.

Have a question you’d like Neil to consider? Mail it to him in care of this newspaper or e-mail him at mailbag@sperrygardens.com. Neil regrets that he cannot reply to questions individually.