Dear Neil: Someone told me that I needed to wrap the trunk of my new pistachio tree. Do you agree? If so, why?
Absolutely. I use the term “non-negotiable” for wrapping the trunks of recently planted Chinese pistachios and oaks, particularly Shumard red oaks, willow oaks and water oaks. The problem for these species is that they all have rather slick trunks when they’re new. They’re grown in nursery rows in their containers, but then we set them out in our landscapes and their trunks are suddenly exposed to full Texas sunlight. The rapid temperature changes and drying from the sun’s rays cause the bark to split. Subsequently the internal wood is exposed. Borers can invade and decay can set in. You’ll see it on the south and west sides of the trunks, and it normally shows up after a couple of years. Apply paper tree wrap from the nursery or hardware store from the ground up to the lowest branches and leave it in place for 18 to 30 months.
Dear Neil: Our daughter has a sago palm in The Woodlands that extends out over her sidewalk. Can they be trimmed? If not, what can be done to make it more tolerable?
She could remove a leaf or two, but depending on where the crown is in relation to the walk, it may be a no-win proposition that would leave the plant flat-sided. It might be better to consider digging it and resetting it a few feet farther back. Those are about the only two options.
Dear Neil: I read your recent article concerning Nellie R. Stevens holly. It sounds like it would make a good choice for a hedge I want to plant alongside my fence. I can let it grow to 10 to 12 feet tall, but I need to keep it at 3 to 4 feet wide. Is that possible?
That’s too much pruning. It’s a larger plant than that. Oakland holly would be a better choice. It’s slower growing, but it’s more compact and somewhat upright. Or if you like the looks of Nellie R. Stevens hollies, a smaller variety that has a similar appearance would be Willowleaf holly. You might be able to keep it within those size boundaries.
Dear Neil: I am having 40 new shrubs planted. How much do I need to water them to be sure they are established?
That’s always a tough question to answer because it depends on the size of the plants and the nature of the soil in which they were grown (since all of their roots are still in the original soil balls for the time being). Stick your fingers down into the soil every couple of days. When it begins to feel dry to the touch it will be time to soak them thoroughly again. For most new shrubs I try to water three times per week from late April or early May into October. I use a garden hose with a water bubbler to slow the flow and prevent washouts. Normal lawn and landscape irrigation alone will not be nearly enough.
Dear Neil: I have several surprise lilies in our backyard that I’d like to share with my son. When can I dig them? They have big leaves on them right now.
Like many of the fall-flowering bulbs, this one (Lycoris squamigera, also known as naked lady lily) produces its foliage in late fall and over the winter. The leaves then die down in the spring. The flowers emerge in late summer or early fall. Digging and moving them is best done soon after the tops die down in May or early June. This is a prized perennial. Bulbs are hard to find and rather expensive.
Dear Neil: My Texas mountain laurel has only bloomed one spring since I bought it eight years ago. What can I do to encourage better flowering?
I’ve grown them since I was a young horticulturist, and I have to say that’s the way they often behave when they’re young plants. They grow slowly as shrubs and small trees go, and they usually don’t bloom reliably until they’ve become somewhat mature. Be patient and you’ll be rewarded. Hopefully it’s in full sun, and ideally it will have perfect drainage. Flowers are sometimes lost in really cold winters as well.
Dear Neil: How can I prune Powis Castle artemesia to keep it more compact? My plants are getting a bit rangy.
Use hand shears to clip the stems back one at a time. It’s the easiest of all artemesias to grow here in Texas, and you can selectively remove just a few stems. It will quickly fill in with new shoots. It’s one of our finest gray-leafed plants for the Southwest.
Dear Neil: My soil test report suggests I apply only nitrogen to my tomato garden. Won’t that result in all leaves and no fruit?
Probably not, but I do understand your concern. To bring everyone up to the same speed, we learn in soil sciences class that there are three major elements that plants utilize in the greatest quantities: nitrogen (chemical symbol N), phosphorus (P) and potassium (K). Nitrogen promotes leaf and stem growth. Phosphorus promotes roots, flowers and fruit. Potassium, or potash, aids in summer and winter hardiness. So common sense would have you believe that plants need some of all three. However, the fact is that most Texas soils, most especially those with a high percentage of clay, hold phosphorus very tightly. It accumulates almost to the point of becoming detrimental to the plants. States are limiting its inclusion in fertilizers, and university soil testing labs are sending back recommendations very similar to the one you received. Trust it and follow it. Your plants will thank you.
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.