Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, February 7, 1993 TAG: 9302080294
SECTION: HOMES PAGE: D-5 EDITION: METRO
SOURCE: John Arbogast
DATELINE: LENGTH: Long
WALNUT TREE MAY BE FOILING EFFORTS TO GROW TOMATOES
Q: I have two questions:1. For the second season in a row all my tomatoes died from blight before harvest. I have tried starting my seeds and using several different disease-resistant as well as non-hybrid varieties. I have also tried planting "new ground," where vegetables had not grown before. Nothing worked. The plants grow beautifully and many fruits form, but they die before ripening. Most of my neighbors have the same problem. Is there any hope for next year?
2. My two-year old Clematis lanuginosa of the cultivated variety called "Candida" grew pretty well and had quite a few flowers, but this past summer most of the foliage turned brown and dry only along the margin of each leaf. Growing right alongside of it, a Clematis viticella of the cultivated variety called "Mme. Julia Correvon" was completely unaffected. Is there a way to prevent that problem this season? D.S., Independence
1. Your work at trying different tomato varieties and locations was good horticulture. However, because of the pattern, including the loss of the tomato plants before the green tomatoes ripened, sounds like "walnut wilt," a problem caused by a substance given off by the roots of black walnuts that persists in the soil and is slowly toxic to tomatoes growing in that soil. Walnut wilt does not affect most other vegetables.
In previous columns I have discussed this problem, which can affect all varieties of tomatoes. Very poorly drained soil could cause poor growth and death of tomatoes, but that likely would cause the loss of other vegetables as well. I am assuming that you have had no trouble growing other vegetables. If you and your neighbors have an abundance of black walnut trees around and you still want to grow tomatoes, your choices are to remove the black walnut trees, wait two years and try tomatoes again, or try raising tomatoes in containers using bagged soil mix.
If you have no black walnuts, wait and see if the problem occurs this year; and if it does, carefully pull up an affected tomato plant and take it to your local Cooperative Extension Office to be sent to the Virginia Tech Plant Clinic. You are served by the Grayson County Extension Office on the second floor of the County Office Building in Independence. Or call 773-2491.
2. Your clematis problem, affecting only the margins of the leaves, sounds like "scorch," which is caused by a plant's inability to supply moisture to the foliage at the rate that the leaves lose moisture.
If there was adequate moisture in the ground, which there must have been because the neighboring clematis did well, the scorching of that one clematis must have resulted from inadequate roots. That could have resulted from that plant's simply being weak, the roots not growing to keep up with the top, or hard or rocky soil close by.
Clematis won't do well in an extremely wet site, but some watering may be required. The leaf-edge browning might not occur this growing season. However, if it does, take a sample of clematis stem with several affected leaves to you local extension office.
Q: I have tried unsuccessfully to grow empress trees (botanical name is Paulownia) from seeds. I have a single tree, which has clumps of seed pods; each walnut-sized pod contains four seeds and numerous white flakes. I have planted dozens of these, but none has even sprouted. Any suggestions? Also, when is the best time to transplant a 4- to 6-foot Paulownia, and are there any special considerations? Finally, when is the best time to transplant a 6-foot Mimosa? T.S., Roanoke
A: Light is necessary for germination of Paulownia seeds; this means that Paulownia seeds that are covered deeply will not sprout. Seeds of this tree supposedly will germinate like grass if placed on the surface of the propagation soil and kept misted. Fresh Paulownia seeds should be used. Seeds of this tree are not dormant when ripe like seeds of some trees.
Late in the plant's dormancy, before new growth starts, is a good time to transplant the Paulownia you asked about.
For more information about this super-fast-growing tree, write to the National Paulownia Center, 4303 Kenny St., Beltsville, Md. 20705-2738.
Transplant your Mimosa at the same time (late dormancy) as the Paulownia. Select a well-drained, sunny site with average soils for both kinds of trees.
Q: Please explain how to propagate mountain laurel. Is this the time of year to begin? We have loads of wild ones. Are these more difficult to propagate than nursery stock? L.V., Floyd
A: According to the "Manual of Woody Landscape Plants" by Michael A. Dirr, the mountain laurel is inherently difficult to root from cuttings, so I can't suggest a good time of year to start.
If you are seriously interested in this, go to a large library and look up the article "Propagation of Kalmia latifolia [the botanical name for mountain laurel] by Cuttings" in the book "Proceedings of the International Plant Propagators' Society 27:479 - 483, 1977." That book also says that mountain laurel seeds should be sown directly on damp peat as a propaging media, but the seedlings are extremely small and hard to work with. you have a question about your plants, garden, lawn or insects, write to Dear John, c/o the Roanoke Times & World-News, P.O. Box 2491, Roanoke 24010-2491.
\ MEDIA GOOFED! Different people have told me that television and newspaper reports have incorrectly called those plants we've seen recently with yellow blooms early forsythias.
Those yellow flowers belong to a plant called winter jasmine that is supposed to bloom in our area in February, so we're not too far off schedule.
John Arbogast is the agricultural extension agent for Roanoke.