Uncommon insect

Dear Neil: I was away for several weeks. When I got home I found that the trees in my backyard had been devoured by some kind of caterpillar. What caused this, and do I need to worry about it next year?
W.P.D., no city given.

Answer: This is an unusual insect that hit parts of North Texas and perhaps elsewhere a few weeks ago. Dr. Mike Merchant of Texas A&M AgriLife Extension did the homework for us and found that this is damage done by an uncommon moth. Here is his report so you can have all of the facts.

Rabbit damage

Dear Neil: I have a patch of my lawn that turns brown like this every summer. I find a lot of rabbit droppings there. Is it possible that the rabbits are responsible? It’s just in this one spot.
G.D., no city given.

Answer: It is highly likely that the rabbits are the culprits if that’s the only place where you see the browning. It may very well be that their droppings are increasing the soluble salts in the soil in that area. Mineral salts, when present in excessive quantities, can actually pull water out of plants’ roots by reverse-osmosis. That causes burning of tree and shrub leaves, and it could lead to this as well. Try watering this area by hand with a hose and water breaker to soak the mineral salts and hopefully to leach them deeply into the soil.

If the hand-watering doesn’t help, and especially if you see rabbit droppings in healthier parts of your lawn, too, push a dowel stick or root-watering rod into the ground in the dying spaces to see if you hit rocks or concrete. If you do, dig them out and remove them.

Columbine seeds

Dear Neil: Can you tell me where to buy Texas Gold columbine seeds?
R.R., no city given.

Answer: It’s a variant of Aquilegia chrysantha var. hinckleyana. Most commonly you’ll have to buy started transplants in the spring, then allow them to self-sow once they finish blooming. ‘Texas Gold’ is a selection identified as a Texas Superstar® plant by Texas A&M. The mother plants are native to only one small part of the mountains of Presidio County, Texas, and I believe the seed source is on protected property. However, if you’ll get just three or four potted nursery plants started next spring, you’ll soon be well supplied with seedlings.

Dying rosemary

Dear Neil: What might have caused my rosemary plant to die back this summer? It was fine until the past few weeks.
D., Plano.

Answer: There has been a great deal of this, and much of it stems back to the prolonged wet weather of spring and early summer. Rosemary needs good drainage. The plants suffered a lot of root loss in the waterlogged soils, and when it finally turned really hot and dry for an extended period of time, the plants didn’t have enough roots to pull them through. Some of us in North Texas also had leftover winter damage to our plants that actually showed up before all the rains moved in. In either event, we’ll probably need to replant next spring.

No blooms on esperanza

Dear Neil: We have several ‘Gold Star’ esperanzas that we’ve had for several years. They came back after the winter, but they didn’t bloom this year. Should we let them come back, or do we need to replant each spring?
B.W., Brownwood.

Answer: Gold Star esperanzas that bloomed in prior years should have bloomed this year as well. However, many of our hot-weather plants got off to a really slow start because of the extended rainy weather in May. In many cases, they were reluctant to bloom, or they were several weeks late in doing so. If your plants survive the winters, it’s absolutely fine to allow them to regrow the following spring. That said, you’re just about as far north as esperanzas will survive.

Crape myrtle aphids

Dear Neil: Why would my crape myrtles’ leaves be shiny and sticky? They started dropping off the branches very early.
E.R., no city given.

Answer: That would be due to crape myrtle aphids. Some years they are really bad, and many years you don’t see them at all. Here is a link to the Pest Control page of our Crape Myrtle Trails of McKinney website. You’ll see information on how to address both aphids and crape myrtle scales should they appear on your plants. The same systemic insecticide applied in mid-May should control both insects with just the one annual treatment.

Damaged live oak

Dear Neil: We planted this live oak tree in January 2014. A couple of weeks later we noticed it was not straight, so my husband put a large strap around it and pulled it until it was straight. Two weeks after that I saw cracks developing where the strap had been. I put paper tree wrap around it to protect it. Recently I removed the wrap, and this is what I found. Should I apply more wrap now? The tree has looked pretty good this summer.
J., Grayson County.

Answer: Probably not. This may be compression damage done by the strap, or it could be sunscald or other damage done by the environment. Take a small fine-toothed saw or a utility knife to cut away the one large flap and any others that stick out. Take care not to peel the bark away, however. Hopefully the tree will produce new bark to cover over the open wounds. If the top growth continues to look good, the tree will probably pull through, but this is rather extreme damage.

Dying landscape

Dear Neil: I’m watching all of my landscape slowly die. Our house faces south. The morning sun is blocked by the neighbors’ house, but the area is in full afternoon sunlight. The landscape is three years old. From the outset, the plants to the right of the front door have struggled to survive. My 10-foot crape myrtles have been overtaken by aphids, and now I’m wondering if aphids might be damaging all of the plants. I’d like to stop the losses. Suggestions appreciated.
R.McD., Red Oak

Answer: I’ve looked at all of the photos you sent. First of all, there is no insect or disease that will attack a wide assortment of plants such as your hollies, crape myrtles and others. Individual pests for particular plants, yes, but not any one pest problem that would be common to them all. That leads me to think about environmental concerns, and that’s where I have to tell you that it really looks like all of these plants have needed more water at one time or another. I’ve encountered the same look in my own landscape several times over the years, where I allowed specific plants (often in their first few years of trying to get established) to go past the point of no return (called the “permanent wilting point”). Hollies, for example, don’t really wilt – they just get very dry, turn an insipid metallic green, then brown and die. Aphids do cause crape myrtles to show shiny, sticky residue on their leaves, but that won’t kill the plants. I’ve had probably 50 posts very similar to yours here, via my newspaper columns, and on my Facebook page this summer, and I’ll bet half of those people left the written conversations thinking I was completely wrong. However, nothing else I have ever seen in 45 years of assisting Texas gardeners would cause such symptoms.

Broadleafed weedkiller use

Dear Neil: Just over a year ago I took out a row of dwarf yaupon hollies. I cut them off flush with the ground, and I sponged Roundup undiluted onto their stumps. They have come back. I have applied more of the Roundup to the new shoots, and it hasn’t done anything. How can I eliminate them once and for all?
S.F., Mesquite

Answer: I’m not sure which of the Roundup products you might have been trying, but you need something with a broadleafed weedkiller such as 2,4-D included, not just a glyphosate. Honestly, at this point I would just soak the bed (or work in it after a heavy rain) and dig them out by hand (and foot) with a sharpshooter spade. Done once, they would be gone. If you ever get to a point where you’re removing other shrubs, pull them out, trunk, roots and all. That’s so very much easier. You can hook a chain around smaller shrubs like dwarf yaupons and pull them out with a riding mower or trailer hitch in just half a minute.

Annual weeds

Question: How can I eliminate this obnoxious weed pest in our beds? I’m so tired of pulling it.
S.S., no city given

Answer: The good news is that it’s an annual, so it has to come up from seeds each spring and early summer. If you can break the cycle one or two years, you’ll not have to put up with it. I have found that hoeing or trimming it down before it can go to seed is a good starting point. Then I put down a 1-inch layer of finely ground pine bark mulch to keep the seeds from sprouting. I rarely have to resort to broadleafed weedkiller sprays (containing 2,4-D) to control the non-grassy weeds in my beds, but if you have no other plants nearby, I guess that could be an option.

Snow-on-the-mountain

Question: I have 60 rural acres in Collin County that are inundated by whatever this is. I don’t want to compromise the underlying prairie grass by spraying. Do you have suggestions?
B.McK., Celina

Answer: This is a Texas wildflower called snow-on-the-mountain. Here is information from the Lady Bird Johnson Wildflower Research Center in Austin.

This plant is a member of the huge and fascinating Euphorbia plant family. One of its most noteworthy sisters is poinsettia. Mowing alone would probably eliminate it if that is your goal, but you could also apply a broadleafed weedkiller spray to the plants without fear of harming your grass. Let your farm supply dealer show you the options. As far apart as the plants are, a quick and high mowing would seem to be an easier option. Or just leave it alone. Odds are, if you do, however, that the population would increase over the years.

Yellowing mountain laurels

Dear Neil: We started a new landscape in rocky soils last December. Two 15-gallon Texas mountain laurels have developed a rather yellowed look in the meantime. I read that iron deficiency causes leaves to have dark green veins, but these leaves are yellow all over. We don’t want to lose them, as they were rather expensive. Thoughts?
L.E., Georgetown

Answer: I have never seen Texas mountain laurels show iron deficiency. In fact, they are native to highly alkaline soils about 150 miles west and southwest of you. They just don’t need that much iron. This looks more like a general shortage of nitrogen. It causes leaves to be yellowed over the entire plant. If you haven’t applied an all-nitrogen fertilizer to these plants in the past couple of months, do so now. Actually, the same fertilizer you use for your lawn would be great. Just be sure it doesn’t have any kind of weedkiller included with it. Apply 1 or 2 tablespoons per plant. Sprinkle it over the original soil balls, and water it into the soil thoroughly. Be mindful, too, not to let the plants dry out. They’re drought-tolerant, but they still need to be grown in moist soil while getting established.

Poke salad

Dear Neil: This plant comes up in our yard every year. It has reddish stems, and the fruit in the fall is purple. Is it anything we need to worry about?
B.R., Arlington

Answer: This is poke salad. It’s an annual or short-lived perennial, and the fruit is a favorite of birds. However, parts of the plant are quite poisonous, so even though you’ll see recipes that include it, you need to do a lot of reading before you take chances with it. I do let a few plants grow in my landscape, but our grandkids all know to leave them alone. Beautiful plant, but one you may or may not wish to keep around. Click to see what the Lady Bird Johnson Wildflower Research Center has on it.

Red Rocket crape myrtles

Dear Neil: We planted three single-trunk Red Rocket crape myrtles on our rural East Texas property four years ago. They get about six hours of sunlight daily, but they have yet to bloom at all and they haven’t grown very fast. Natchez crape myrtles that are planted nearby are growing and blooming well. Is Natchez just a faster grower?
J.K., Woodville

Answer: Red Rocket is a very good variety that grows almost as quickly and to almost the same height as Natchez. However, six hours of sunlight would be a bare minimum for any amount of blooming. The appearance of the grass and crape myrtles make me think these plants might not be getting nearly enough water. Even with shade, if crape myrtles are kept moist and well nourished, they will grow vigorously. At that point you will know more about the light as it relates to blooming. Crape myrtles bloom on new growth, so you have to have those new shoots in order to get blooms.

Dead spots in bermuda

Dear Neil: What might be causing these random dead spots in our hybrid bermuda lawn? I’ve given it plenty of water and fertilizer. Help if you can.
R., Kennedale

Answer: If this were St. Augustine, I would suspect chinch bugs. The symptoms and location (full sun, hot spots) are perfect. They do attack bermuda occasionally, so I would still get down on my knees and part the grass at the interface of dead and healthy turf. Look for small, black insects with irregular white diamonds on their backs, and if you see them, apply a labeled insecticide followed by a good watering.

If you don’t see the insects (which will probably be the case), this is likely to be Pythium blight, otherwise known as cottony blight or southern blight. It is a disease of abundance, often showing up where fertility levels are high and soil is kept very moist. This has been fairly common this year. Fungicides don’t help very much, but they’re still worth applying. If you decide this is the problem, try to maintain the grass with a more modest level of watering and feeding. Here is a link that might be of help.

Finally, if you have an automatic sprinkling system, do turn that station on to see if there could possibly be something wrong with the heads and their spray patterns.

Bagworms

Dear Neil: How damaging is the pest that creates these cocoons on several varieties of junipers? I’ve picked off hundreds. Isn’t there an easier way?
M.R., no city given

Answer: These are bagworms, and they have been noteworthy this year for two different reasons. First, the populations have been huge, and second they have shown up a month later than usual due to the cool, wet spring. In normal years, the tiny cocoons first show up in late spring (mid- or late May), at which time they are no bigger than pencil points, bags and all. The larvae are quite mobile then, pulling the bags around behind them. Then, a month or so later, the caterpillars quit feeding and tie their bags to the twigs. They will persist there until next spring, when adult moths will emerge, fly, mate and start the cycle over again. The best way to deal with these is to watch in May and early June, and when you see the first defoliation and small bags, spray with almost any common garden insecticide. Bacillus thuringiensis is the most universally effective control for all caterpillars, plus it’s organic. That will stop them from any further feeding for that entire year. This late in the season, however, you’re left with no option but to pull them by hand.

Peach problems

Dear Neil: What is going wrong with my peaches (for the second year), and what can I do to stop it?
A.A., Grand Prairie

Answer: It looks like your peaches have been invaded by both insects and disease. Plum curculios attack both plums and peaches. They are small larvae that devour the flesh of the fruit, leaving congealed sap plugging their exit holes. Spraying to protect against them begins in late winter as the flower buds are swelling, then continues on until a couple of weeks before harvest. As for the rotted fruit, that’s brown rot. It has been unusually troublesome this wet year. Include a fungicide with your insecticide each time that you spray. Here are a couple of links that should be of help.

From my own website’s FAQ pages.

And from Texas A&M’s horticulturists.

Crape myrtle insects

Dear Neil: We have these insects on our crape myrtles. We have ruled out webworms. What are they, and how do we deal with them?
S.L., North Richland Hills

Answer: There are many species of webworms and tent caterpillars. It certainly looks to me like that’s exactly what you have here. Break open the webs with a coathanger or pole pruner. Birds will come to feed on the larvae. In fact, while you’ll breaking the webs open, just pull out as much as you can. You could spray with Bacillus thuringiensis combined with one drop of liquid dishwashing detergent per gallon of spray to break up the surface tension on the webs, but you’d still have the webs to look at. Pulling or pruning them out is the simplest solution.

Wildflower weeds

Dear Neil: What are these weeds that we have growing beneath our bur oak? They open in the mornings and close up at night.
D.G., no city given

Answer: It’s a little hard to see the plant due to focus, but I’ll bet it’s a partridge pea. They are fairly common wildflower weeds in Texas, especially when we have good moisture. Mowing will probably eliminate almost all of them (and other weeds), but I guess in a pinch you could apply a 2,4-D broadleafed weedkiller specifically to the weeds. Your local independent retail garden center can show you a couple of products that contain only 2,4-D. Most of the combination herbicides contain one or more ingredients that can do damage through trees’ roots, but products that have only 2,4-D will not.

Here is a good photograph and an interesting piece of writing about partridge peas.

Cankerworms on pistachio

Dear Neil: My Chinese pistachio leafed out very sparsely. Could it have been too much rain? Neighbors’ trees look just fine.
K., Allen

Answer: I’m betting this is old damage done to the first leaves of spring by a looping caterpillar known as cankerworm. The tree has been busy putting out new leaves at the ends of its branches. It will be fine. For the record, you’ll see trees side by side in the forest. One will be ravaged by the pest, others next to it, not. The tiny larvae hang by thin threads in April, eating new leaves as quickly as they emerge. You can control them with Bacillus thuringiensis then, but there is no call to action now.

Paper mulberry

Dear Neil: How do I get rid of this tree/weed? It has long roots all over my yard.
S.O., no city given

Answer: This is paper mulberry. Apparently your opinion of it is about the same as that of the invasive plant experts in Florida. I grew up with this on my folks’ small rural farm in Brazos County, and our repeated cutting and stump-pulling got rid of it. If the stumps are large enough after you cut them back level with the soil, you could drill holes into them and pour a broadleafed weedkiller in to fill the holes. It would be carried out to the roots, and it would keep so many sprouts from redeveloping. But it may take awhile.

Possum grape

Dear Neil: Is this plant worth keeping? I’ve fought it for years, but I decided just to let it cover my fence this year. Is it harmful? (I see that it has three leaflets.)
R.P., Midland

Answer: I love this vine. It’s Cissus trifoliata, and it goes by the great common names of possum grape and cow-itch vine. It is native to much of our state. I first saw it as a youngster working alongside my dad in his Texas A&M herbicide plots north of Uvalde, but people have asked for help identifying it from all over the state. Whether you decide to keep it or not depends totally on whether you like its looks and want it where it’s growing. Here is what the Lady Bird Johnson Wildflower Center says about it.

Dying viburnum

Dear Neil: What might have caused our viburnum to die? Is it because we pruned it recently?
B., no city given

Answer: I’ll do the best I can to answer, but the photo was in extremely low resolution and I don’t know where you are trying to grow it. Viburnums are best adapted to the eastern third of the state. I’m guessing that’s where you are from the surroundings in your photo. I’ve grown viburnums most of my life, and there are almost no insects or diseases that attack them commonly. Some types are tender to winter cold, but the damage would have shown up in February or March, not in the summer. Pruning would not have caused damage at all. I’m going to have to guess that there is either trunk or root damage. Look at the trunk for any signs of trauma you might find (trimmer damage, rodent chewing, etc.). Think back to the rainy weeks in May and early June, and consider whether the water table in that area could have been high enough to do damage. Thousands of plants in Texas were lost due to our waterlogged soils.

Scale on crape myrtles

Dear Neil: I have a row of seven lovely old crape myrtles. They have had scale insects, and now I see this white ooze coming out. What is it, and what can I do to stop it?
E.E., no city given

Answer: All that I see on this trunk is scale insects. If you press on them, they will be filled with dark red fluid. Apply a systemic insecticide such as imidacloprid immediately to lessen this year’s population. Make that same treatment in mid-May next year to get ahead of the curve. Here is what we have on our Crape Myrtle Trails of McKinney website. Scroll toward the bottom of the page.

Dallisgrass or crabgrass?

Dear Neil: I think our garden has been overtaken by dallisgrass this year. How can we get it back, even if it means starting from scratch? It has cosmos, gomphrena, lantanas and morning glories. It also has three tree stumps left over from the removal of the trees. Without using a grinder, how would you recommend getting them out?
N.W., no city given

Answer: This is not dallisgrass. The photo is extremely low resolution, but this appears to be an annual weed, not perennial. My guess is that it’s crabgrass. If this were my bed, I would mow all the weeds, then I’d strip off about an inch of the topsoil to get most of the seeds that have already formed out of the way. I would incorporate 4 or 5 inches of different types of organic matter, and then if I were amending a clay soil (I don’t know where you live), I would also add 1 inch of expanded shale. I would rototill it all to 12 inches deep. You would be able to plant fall annuals now, but apply 1 inch of pine bark mulch to discourage seeds from germinating again.

Lace bugs

Dear Neil: I have a chinquapin oak that was planted last October. It looks like it has rust-like stuff on its leaves, and the undersides look like there’s something there. Any suggestions?
C.M., no city given

Answer: Your chinquapin oak has lace bug damage. Left unchecked, these insects will turn the leaves manila-folder tan within the next couple of weeks. Active lace bugs are fairly easily controlled with any general-purpose insecticide. Next year you might apply a systemic insecticide to the root area in early to mid-June to prevent their damage for the season. The black specks are their excrement, as they feed from the backs of the leaves. The specks are not of major concern other than the cosmetic effect they have.

Mulberry seedling

Dear Neil: Should I leave this tree-like plant? It is growing so rapidly. It came up as a seedling.
B.McK., no city given

Answer: This is a seedling mulberry tree brought to you by birds. It will grow to be 35 feet tall and wide, and it will consume a huge amount of water each summer. Because of the mess the fruit makes, most people opt not to grow these, which is why you’ll not see them being sold in Texas nurseries. We are “gifted” with probably 25 of them in my gardens each year, and I faithfully remove them all. By the way, what you see in the photo is juvenile foliage. If you leave the tree to mature, its new leaves that develop on down the line will be of the more traditional shape.

Tree trunk growths

Dear Neil: Do I need to worry about these growths on the trunks of my crape myrtle tree? They seem to be multiplying.
L.M., Fort Worth

Answer: These are burls. They’re the result of abnormal growth of the stem tissues of a tree or shrub. In some forest trees, burls are among the prettiest of all of our lumber, usually used as thin veneers due to their scarcity. In most cases, the cause is uncertain, but I would definitely remove any stems that have them at this point, probably completely to the ground or at least flush with another healthy branch. I have seen them before on a crape myrtle near a bank in Frisco, also near a country club in McKinney, but they’ve always been solitary.

Tree choices

Dear Neil: I’m considering another shade tree for my backyard. You see my young live oak. I would really like another, but I’ve also considered a cedar elm. Distances are deceiving. The trees would be spaced 32 feet apart, 15 feet from the fence and 26 feet from the house. We may add a covered patio by the windows just behind the flag. The patio would come out 16 feet from the house, making it just 10 feet from the tree. I don’t want a tree with surface roots that could interfere with the patio. Am I on the right track with the live oak idea?
S., Frisco

Answer: Live oaks grow to be 50 or more feet across, so I’d be cautious about putting two in an urban backyard. Plus, they are notorious for the large surface roots that actually become a part of their natural look and charm. Cedar elms grow egg-shaped (a bit more upright than spreading). They are also very large at maturity. I would at least consider Little Gem southern magnolia or its little sister called Teddy Bear.

Yellowing photinias

Dear Neil: Three of my many photinias in a row are turning yellow and their trunks seem to be cracking open. The others still look fine. These are a critical part of my landscape. What is happening?
D.L., St. Paul

Answer: This could be simple iron deficiency, but odds are very strongly against it. Unfortunately, I fear that it’s Entomosporium fungal leaf spot, and it looks like it’s fairly far advanced. We do not have a reliable fungicide for that disease, which has relegated what used to be a good large screening shrub or small tree to a plant that few landscapers use any longer. If you see any leaves with maroon freckles, that’s how the disease gets started. Here is a photo I took three months ago in McKinney.

Rainfall damage

Dear Neil: We planted this 95-gallon Chinese pistachio the first week of March. The nursery had very specific instructions for May through October, i.e., to give it 71 gallons of water every other day. Because of all the rain we had in much of April and all of May, we did not water it. We reset the watering schedule on June 5, and today as I send this (June 8), I see all these yellow leaves with brown spots. Is this evidence of too much water? We have clay soil.
L.L., Bonham

Answer: Yes. This is a question thousands of Texas gardeners have repeated time and again this spring. It is not insect- or disease-driven. Good plan not to water while the soil was already wet. I’m surprised by the suggestion to add that much water that frequently in a clay soil environment. My long-held policy has been never to water wet soil. The only other thing I would suggest you do at this point would be to wrap the trunk with paper tree wrap to protect it against sunscald. Oak and pistachio trunks are especially vulnerable. Leave the wrap in place for the first two years.

Invasive ivy

Dear Neil: I looked through your website’s FAQs, but I couldn’t find information about how to rid my beds of invasive ivies. Nothing seems to kill them. Help!
S.C., Brenham

Answer: You have two of the most tenacious of all of our weeds. You have smilax briars (with the thorns) and snailseed vine. Simply cutting the vines to the ground is a start. Smilax, especially, can be killed simply by removing its top growth. You’ll still have 10 or 20 percent of the plants that will regrow from their roots with both of these plants, and that will take you to the second step. Weedkiller sprays aren’t very effective on either of these vines, and you can’t use them anyway if “good” plants are nearby. Therefore, a sharpshooter spade becomes your best friend. Dig out their root clusters. You may find tubers with the smilax, and you’ll find woody, fibrous roots with both plants. But if you get the crowns of the root systems, those plants won’t come back.

Infested euonymus

Dear Neil: My golden euonymus is dying. Whatever this is has started killing branches. What is it, and what should I use to control it?
S.B., Southwest Fort Worth

Answer: Your plant is infested with euonymus scale. They are the primary reason almost no landscapers use this shrub. Once they gain this kind of hold over a plant, it is almost impossible to turn the problem around. The recommendations are to apply horticultural oil in January or early February and summer-weight dilutions of the same product now. There are other systemic insecticides that also list scale as pests they will control, but it’s a long and steep hill and the results are never really perfect. If I were suddenly to move into your house, I wouldn’t spend a dime trying to save infested plants. (Sorry for the blunt comment.) I would start investing in their replacements to be planted this fall.

Failing plum tree

Dear Neil: Whatever hit my plum tree was sudden and thorough. It did bear a lot of plums this year. I think it’s gone, but was it due to the wet weather?
No name given, near Forney

Answer: Whatever the problem is, it’s near or below the ground line. I agree on the wet soils as a major consideration. I also see evidence that the trunk has cracked. Did the tree tip over at some point? Finally, check the trunk for evidence of peach tree borers having invaded it. You would see waxy globs of congealed sap. I don’t see them in your photo, but it’s an easy check to make as you remove the tree.

Rose rosette virus

Dear Neil: Attached is a photo of my Knockout roses. Are they infested with the dreaded Rose Rosette?
T.M., Rockwall

Answer: Rose rosette virus has taken a horrible toll in Texas rose gardens over the past several years, and no varieties are any more devastated than the Knockouts. That said, I do not see evidence of it on these plants. So that you can see it first hand, here is a link to the information and photos I have archived on my website.  And here is a short video piece I taped a few days ago.

Leaning tree

Dear Neil: My young redbud tree is leaning. What can I do to straighten it? Should I trim the branches?
K.H., no city given

Answer: Trimming limbs away from the “heavy” side will certainly help, but the improvement may only be temporary. Unfortunately, the trunk is always going to lean unless you dig and reset the tree in the winter. I wonder why it has such a lean. The Leyland cypress seems far enough away not to be casting shade, but if something else is creating heavy shade on the “lighter” side of the tree, it’s just going to grow right back with a lean. At that point, I have to hand it all back to you.

Aphids or insect galls?

Dear Neil: This great tree has served our family well for 20 years, and now I’d like to return the favor. It’s made it through our terrible West Texas drought and a horrible hailstorm two years ago. This year it’s had ample moisture. Now I’m told it has aphids, and its leaves are turning yellow. The systemic insecticide the nursery sold me hasn’t worked. Any suggestions?
I.G., Lubbock

Answer: The yellowed leaves are probably related to all the moisture and high humidity – something you haven’t encountered any time recently. I would expect that the tree will shed some of the affected leaves and then bounce back. The bumps you’re calling aphids are actually insect galls. There are scores of types of galls that attack a wide variety of plants, from oaks and pecans to hackberries and elms. They do almost no harm to plants, which is good, because we have no means of controlling them. The adult female insect stings the plants and lays her eggs. She is there for only a short period of time. The larvae develop within the protection of the gall, so insecticides have little or no impact on them. No harm. No call to action.

Trunk cavity

Dear Neil: The crotch of our oak tree collects water. Does this harm the tree? Should we put pea gravel or stones in the cavity to help drainage? How can we stop mosquitoes from breeding there?
C.H., Southwest Arlington

Answer: Odd as it may seem, trees are able to wall off from damage from standing water in situations like this. Do not put anything in the cavity. Periodically, rinse or blow it clean, but do nothing else. You could put one tiny drop of oil on the surface of the water and stop mosquitoes. You could also put a few drops of insecticide in. The tree will most likely grow enough to fill in the cavity with its own tissues.

Grassburs or sedge?

Dear Neil: I have about an acre and a half of centipede grass. Grassburs are everywhere in my lawn. How can I get rid of them? I mow them off, and they produce seeds within just a short while later.
N.B., Winnsboro

Answer: Please do me a favor. Dig up one of the plants and roll its stem between your thumb and index finger. I suspect it will be triangular in shape, and if so, you have sedge, not grassburs. The flowers and heads that are produced also won’t be painfully prickly. If that’s the case, one of the nutsedge killers such as Image or Sedgehammer will probably help. Buy a small amount and try it for six weeks. These materials take a little longer than conventional herbicides to show results.

In the chance that you have grassburs elsewhere in your lawn, there is no post-emergent herbicide that will kill them. Your only option is to apply pre-emergent granules (Team, Dimension, Halts, Balan) to keep them from germinating in the spring. Where you are, that would be early March and 90 days later in early June. Once grassburs have sprouted and are growing, there is nothing more you can do to stop them until the following spring.

Boxwood

Dear Neil: What should we do with this boxwood? It looked like this a year ago when we moved in. Will it grow back, or should we just remove it?
T.G., McKinney

Answer: You can probably make a case for either action. It will grow and fill in if you give it time. You can speed things along if you carefully prune the dead wood out of the top growth. You’ll want to reshape it in the process, so you’ll probably end up cutting growth back by almost half, one branch at a time. On the other hand, if that will leave a gap in your landscape bed, nurseries certainly have nice plants that could be put in in its place. If it were mine, I’d trim it and give it a chance.

Groundcover removal

Dear Neil: We moved into this house a while back. The previous owners had planted groundcover here, and I’m considering removing it and making an area where our grandchildren can play. Can I safely use Roundup to kill it without killing the trees? Also there are two kinds of groundcover here. Do you see poison ivy in the photo?
G.E., Plano

Answer: You’ve asked my opinion, and I would not take this planting out. It took it a long time to fill in so nicely. It could certainly be tidied up in an hour or two. A line trimmer would trim it off the house. You could even use the trimmer to get it away from the fence, but let the line aim down to the ground and not into the wood of the fence. You could remove it by hand from the crape myrtle trunks. (Line trimmers can be quick death for trees.) As for the question about poison ivy, I do not see any. I do see Virginia creeper with its five-part leaves. It is harmless to you, but it will overrun the English ivy groundcover, so you do want to trim it out.

Oh, and my other reason for not trying to convert this to a play area for grandkids is that, at least in my own experience, they don’t play outdoors much anyway. You wouldn’t have room for a fort or a swing set in this spot, and the noise and heat of the air conditioners would be unpleasant to them. But that’s just one guy’s opinion. As for the Roundup question, if you use the original glyphosate-only Roundup, you should have no problem.

Leaf-footed bugs

Dear Neil: I have found these insects on my althea leaves. Only on one plant, and only on this one leaf. What are they, and do I need to worry about them? I did wash them off with a hose.
O.P., Arlington

Answer: These are young leaf-footed bugs. I had a lot of questions about them several weeks ago, but fewer more recently. While they can be harmful to plants, their populations usually don’t justify doing much more than what you did. General-purpose insecticides will control the young bugs. Fully grown adults will be more difficult. My bet would be that you didn’t see them again.

Spider mites on plumeria

Dear Neil: What is wrong with my plumeria? It keeps looking this way, almost as if it had been burned by sunlight. I have it in a bright spot, but with no direct sunlight. Is there a spray I should use? Would spiders be the problem, or some disease?
No name, no city given

Answer: Thump one of these leaves over a sheet of white paper. You should see very tiny specks start to move around freely. Those aren’t spiders, but the much smaller spider mites. I would suggest you take a bucket of warm water with a drop or two of liquid dishwashing detergent and two very soft sponges. Put one sponge in each hand and pull them (dripping wet) from the bottom end of each leaf to the tip. That will wash the leaves clean of the mites. Repeat it weekly for a month. The detergent doesn’t actually kill the mites, but it will make it easier to wipe them off the leaf surfaces, both top and bottom.

Holly growth

Dear Neil:These two yaupon hollies are several years old. They were from the same source and planted on the same day, yet they have grown to be this different in size. This leaves an unsightly gap. Would you suggest standing pat hoping that the smaller plant catches up, or should I move the smaller plant to another spot and possibly put in a tree such as Little Gem magnolia or Shantung maple?
M.D., DFW area

Answer: The smaller plant looks fantastic. Sure, it’s more compact, but it’s also nicely filled. I wouldn’t touch it. Consider trimming the taller tree branch by branch to groom it and even its height up with the smaller tree. As they continue to grow, they will probably be at a more even pace. You could also guide their growth so they would come together. It doesn’t look like you have room for a much larger tree like the two you mentioned in the spot where the smaller yaupon is now. It looks like a magnolia or maple would soon grow into the tree at the left edge of your photo.

Confederate jasmine

Dear Neil: Do you have any idea what is causing this discoloration in my Confederate jasmine plants?
U.D., Houston

Answer: These leaves are dying. The only things I’ve seen cause this in my 55 years growing this plant have been cold damage (not likely in Houston) and drought (even less likely this year in Houston). I have never seen any insect or disease bother either Confederate star jasmine or its sister, Asian jasmine. I’m left to wonder if there might have been water standing around this plant for a period of time, or at least a very high water table for a week or more. I’m assuming these plants have been growing in your landscape for a year or more. If they are brand new plants, perhaps they got too dry just before you set them out. They really don’t give you much warning. They don’t wilt. They just change to a drab shade of green before they look like this.

Crape myrtle damage

Dear Neil: My crape myrtles have dead limbs at their tops. I’ve never seen them do this before. What caused it, and what should I do?
D.L., St. Paul

Answer: This is cold damage from this past winter. It has been rather widespread across the northern half of Texas. Some varieties were impacted more than others. Yes, trim out the dead growth and reshape the plants as needed. Here is a more detailed post from my website.