I love your e-mails, and do my best to answer each and every one of them, as you who have written know. Frequently, I share your questions and my answers in print. Here are a few recent queries.
I lose my full-sun lawn every summer to brown patch. Since it is only 800 square feet, it is manageable to reseed in the fall. This year I seriously applied Daconil in the curative rate, two or three times a month, beginning in April. It failed. Since Daconil doesn't work, is there something else I could use? Each fall I get seed that is recommended for this area, and it fails. So are there any grass alternatives that give a person a better chance of avoiding brown patch?--Frank Sobol
I just fought brown patch on a client's property. It appeared as dead flat patches of grass and has been an especially widespread problem on lawns this summer. Daconil was a successful treatment in our case. But, as you now know, it doesn't always work. There's also a new fungicide on the market that is labeled for brown patch and is applied in very small amounts, making it more environmentally friendly. It's called Heritage. But, with the help of fungicides, I believe that the lawn we cared for recovered fully because the turf had been growing in deep, rich topsoil.
It may be necessary to reseed your lawn one more time to correct the problem. Before doing it this fall, get a soil test through your local garden center or cooperative extension service. Then perform the following tasks:
Aerate very thoroughly with a plug aerator, available from a tool rental company. Run the aerator over the turf many times to punch lots of holes. Amend the soil, adding lime and/or fertilizer to adjust the pH or nutrient level as per the results of the soil test, then sprinkle compost into the aeration holes with a broadcast spreader or shovel. This will give you a growing medium that'll help your lawn cope with diseases.
Seed the lawn with a disease-resistant, compact turf-type tall fescue blend at a rate of about four to five pounds per 1,000 square feet. Make sure there are at least three different named types in the blend to ensure best disease resistance. Then all you need is rain or a lawn sprinkler to keep the grass seed moist while it is established.
I have many azalea bushes, and some are 60 years old. In the last few years I have noticed random leaves on a branch beginning to wilt, and then the whole branch dies. This occurs with no particular pattern, and not on all bushes. I thought it to be winterkill, but this does not seem to be the case. I would be very grateful to know how to control this problem.--Klaus Hirtes
It sounds like a classic case of a root rot. I have seen it occur on many plants in the heath family, of which azaleas are members. This is not good news because there's no effective chemical control. Judging by your description, it could be phytopthora, usually caused by poor, impermeable or wet soil. Azaleas can outgrow and survive the disease, if they get even moisture and good drainage.
Try to correct the situation by laying compost over the roots and digging it down three to four inches around their perimeter, which is about at the edge of their leaf spread. Spading organic material around a plant's roots is called vertical mulching and will help achieve the perfect moist, well-drained balance that they need for good health. For more information on root-rot diseases, call your cooperative extension service.
I have been trying to use rhododendron and azalea stem cuttings to create seedlings, but they don't survive. Is there a trick to starting rhododendron seedlings?--Jackie Korat
You can root rhododendrons and azaleas from softwood cuttings (no woody bark) in summer. It can still be done now.
Cut the stems for rooting from the new growth on the plant, about four to six inches long. Pull off lower leaves and dip stems into a rooting hormone, such as Rootone. Place stems into a container of perlite, which you can get at your local garden center, and keep them wet. They'll root in several weeks. Then you can plant them in a bed outdoors that has lots of leaf-mold compost mixed with the soil. Protect them through winter with a shade cloth such as one called Sunscreen. In spring, transplant the new plants.
There also is another way. Simply scrape a little of the bark on the low-growing outer stems of the plant. Then put leaf mold around each and place a rock on the leaf-mold-covered stems to hold them down onto the soil until they grow roots where the stem touches the ground. This could take several weeks or months, depending on the amount of moisture. Once you see that a stem has rooted into the soil, prune it away from the parent plant and transplant to a new location. Spring is the best time to cut them away and transplant, provided that they have grown a small cluster of roots by then.
Could I plant an aucuba by my patio this time of year? If not now, when is the best time?--Wallace K. Babington
Aucuba can be marginally hardy to our winters. I recommend that you wait until April. That'll give it more time to grow and establish feeder roots, which will make this large-leafed, shade-tolerant evergreen more likely to survive its first winter on your property. You can get aucubas that have deep green or gold variegated foliage. They like moist, shady sites that are rich in organic material, so plant it with lots of compost.
Write on! And keep reading "Green Scene."
Lerner is president of Environmental Design in Capitol View Park, Md. His e-mail address is email@example.com