Ask Neil

Would you like Neil’s help with your plant question? Send the question along with a digital photo by clicking here. Along with the photo you also will need to include your initials and the city in which you live. Neil will select 3 to 5 questions of the most general reader interest for answering in the next issue of neil sperry’s e-gardens. Unfortunately, Neil cannot respond individually by return e-mail.

What is killing my evergreen trees? What can I do to help them come back?

G.S., McKinney

Answer: These are Leyland cypress plants, and the only things that could have killed them this way would be either getting too dry at some point last summer (although there were all those unusually rainy weeks) or some extraneous chemical such as a weedkiller that got too close to them. If they are served by a sprinkler head you might check to be sure it still can spray that far (maybe some of the branches now block it). Spider mites will sometimes attack them, but they would have gotten tree number 3 at least to some lesser amount. Bagworms often attack them, but they leave no needles (not the case here). As if all that weren’t unsettling enough, the mature size of these is 25 to 35 feet wide. These plants are way too close together and will eventually denude one another. It’s a great evergreen when these problems don’t arise. Sadly, however, these won’t come back.

We have put out pre-emergent for grassy weeds and broadleaf weeds, both last spring and fall. We have been unable to control this one. It is in bloom now. It seems we brought it in in a load of topsoil, as we are the only ones in the area that have it. We have a very high water table. It is now coming up in my flowerbeds. Hopefully you can tell me how to control it.

B.C., Mabank

Answer: The weed appears to be a member of the lily family. Many of them such as wild onion develop bulbs like your weed has done. You could use one of the 2,4-D broadleafed weedkiller products that is labeled for wild onions and get some degree of control of it. I showed your photos to representatives of two of the nation’s leading manufacturers of garden products and they both felt those 2,4-D products might offer help, but that total control would require diligence. They suggested you check the label of Image as well.

My hardy hibiscus plant did not bloom last year for the first time in the 5 or 6 years that I have had it in this pot. Do I need to divide it before it starts growing vigorously this spring?

D.K., Plano

Answer: This plant needs to be set out into the ground. Hardy hibiscus do best in full or nearly full sunlight. Plant it into soil that has been amended with generous amounts of organic matter and keep it moist at all times. It’s just rootbound. I’m amazed you could keep it more than one year in a pot like that.

What is wrong with my holly bushes? They just don’t green up. I used my regular lawn food last summer and they still looked like this.

P.R., Austin

Answer: This Chinese holly foliage shows severe iron deficiency, also known as chlorosis. Apply an iron additive that also contains sulfur. The iron will green up the foliage while the sulfur helps create an acidic soil in which the iron can remain soluble for uptake by the plant’s roots. Keep all iron products off masonry and painted surfaces that could be stained.

Posted by Neil Sperry
Back To Top