Neil Sperry: Patio roses could be infected with rose rosette virus – San Antonio Express-News

Q: My roses bushes are in large pots on my patio, but they have a disease. When I put new plants in the pots, do I need to have new soil for them? Is there anything I can spray on them that will cure this disease?

A: Oh, I so wish you might have attached a photo of the disease. Roses have many diseases. Black spot is most common, of course, and some people confuse damage of thrips with diseases.

However, almost all of the questions Ive gotten over the past 10 years relative to rose diseases have been about rose rosette virus (RRV). It is spread by a wind-blown microscopic mite. Contrary to what some may try to get you to believe, there is no prevention nor any cure.

And none of these three problems is soil-borne, so changing the soil wont offer any help. In fact, if you have RRV in your neighborhood, its time to change to some other types of flowers until a workaround for the virus has been determined. It has been more serious in some parts of Texas than others, notably in Dallas-Fort Worth.

Those of us who have seen far too much of it recognize it on sight. It causes clubby new growth on rank-growing stems that have several times the normal numbers of thorns. The buds do not open properly, and over the course of a year or two, the plants lose vigor and die. As soon as its presence has been determined, infected plants should be dug and removed, put into plastic trash bags and sent to the landfill.

Q: I cannot find a local business that sells Carissa hollies. Any advice?

A: Without knowing where you are or where youve tried, I cant offer much specific help, but what I would suggest is that you talk to the owner of your favorite independent retail garden center. Carissa hollies are the best-selling dwarf hollies in Texas today.

Wait a few weeks until they are stocked up for spring. I would expect that almost every independent retail nursery in Texas will have them in stock. If they dont, they can easily order them in for you.

Q: At our place in the Texas Hill Country, we have a row of five elaeagnus plants that we set out to replace some old and tired hollies. The new plants had done well until the middle one suddenly died.

Cotton once was grown in this soil, so I wonder about cotton root rot. Weve had the property for 30 years and have never had this happen before. What might the cause be?

A: Ive grown and observed elaeagnus for all of my life. Ive rarely seen them die unexpectedly. Lace bugs are the main problem they encounter, and they only cause the plants to lose their color, not to die.

Your photo does look like cotton root rot. Its a soil-borne fungus that can remain dormant in the soil for many years before it attacks susceptible plants. Hollies are highly resistant, which would explain why they would not have died.

Elaeagnus are listed by Texas A&M as tolerant, meaning they will occasionally succumb. So that could be the problem, or this plant might have been hit slightly harder by last summers drought so that it was impacted more than the others. That happens all the time.

Its one or the other, but thats as close as I can come.

Q: We had to have our live oak tree cut down and the stump and surface roots ground out. They were threatening our foundation. How long before the other roots will decay? We want to plant new sod there. Our yard is just too small for trees as large as oaks.

A: HOAs and cities that require two trees in compact urban lots should never recommend live oaks and other large shade trees. Its easy to forget that a tree thats 8 or 10 feet tall with a 2-inch trunk will eventually grow to spread 75 feet and cover an entire city lot.

Those old roots will eventually rot, but it may take many years. They may even try to send up tons of new sprouts this spring. In all candor, it might be easiest to get the folks with the root grinder back in to finish their job. I doubt if youll be able to dig them out by hand.

Q: We hired a lawn care company to care for our yard for the first time last year, but the backyard looks terrible. They didnt pick up the leaves, but merely mulched over them.

Since three large trees contributed to the leaf matter, I feel like the grass was smothered. Could they have brought disease in from other lawns they tend? Do you have any ideas?

A: I doubt if they carried diseases in. You really do need to remove leaves over the three- or four-week period of heaviest leaf drop in autumn to keep from having way too much organic matter being put back into the soil in a short period of time.

Its also possible that all of that shade has weakened your grass, so the decline may have nothing to do with the lawn care company. In the meantime, do get the leaves off the lawn each autumn. Put them into the compost pile or use them as a mulch in flowerbeds.

Mail questions to Neil Sperry, c/o Features Department, San Antonio Express-News, P.O. Box 2171, San Antonio, TX 78297-2171, or email him at SAENgardenQA@sperrygardens.com.

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Neil Sperry: Patio roses could be infected with rose rosette virus - San Antonio Express-News