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Q. Three years ago I planted several white pine trees about 6-feet tall. They were doing very well. Then, a short time after a disagreement with one of my neighbors, my pine trees started to die. I planted six trees and every OTHER ONE died. Now I have another maple tree that is dead. I strongly suspect that someone has sprayed some of these trees with Roundup or some other kind of poison. Is there a company that will test and analyze ground samples, branch samples and root samples to find out if these trees were poisoned?

A. It is difficult to distinguish symptoms of herbicide injury from many other look-alike symptoms caused by transplant shock, drought, insect pests and disease. If a herbicide is involved, there would be some intermediate symptoms prior to plant death, such as yellowing foliage, leaf scorch, and possible twisting and distortion of new growth, depending on the specific type of herbicide. But other factors can cause similar symptoms. It is even more difficult to determine the causal agent once plants are completely dead.

There are companies that run herbicide screens, (testing for residues), but one would have to know which specific chemicals to test for. You’ll find a list of certified laboratories online at http://www.agry.purdue.edu/ext/soiltest.html. Contact the labs directly to discuss types of tests, prices and what samples they will need.

When misuse or damage from the use of a pesticide is suspected, the Pesticide Office of the Indiana State Chemist has a process for filing complaints. You’ll find information about that protocol at http://www.oisc.purdue.edu/pesticide/pesticide_complaint_investigations.html.

Q. Regarding “no-mow” grass, I think zoysia grass is more of what your reader was talking about earlier this spring. The only drawback is that this grass goes brown in the fall and is slow to green up in the spring, but it is very slow growing.

A. Actually, zoysia is not what I would consider a “no-mow” grass. Zoysia grass is a warm-season turf species that grows best in Indiana during the months of June, July and August. And, though it may be a viable option for Southern Indiana, it is not particularly recommended for central or northern portions of the state. During the summer months, zoysia needs to be mowed frequently, about twice a week or more, to maintain the turf at one-half inch. Zoysia also tends to develop a thick thatch layer. It is very slow to establish, but, thereafter, does an effective job of out-competing most weeds. Zoysia is also fairly expensive, usually needing to be started by sod rather than seed.

For much of Indiana, zoysia is indeed very slow to green up in spring and quick to brown in fall and is not very tolerant of traffic when dormant. So during the cooler spring and fall months when bluegrass thrives, zoysia will be dormant and brown and, thus, will not need mowing. But it will also not be an attractive ground cover for most of the year. Zoysia will not tolerate shade and, in the sun, it becomes aggressive into flower and shrub beds. We get more inquiries on how to get rid of zoysia than how to establish it!

For more information on zoysia lawns in Indiana, see Purdue Extension agronomy publication AY-6 online at http://www.agry.purdue.edu/turf/pubs/ay6.htm.

Q. When they moved the trailer where I live, they took off the topsoil (it was a field before). Now my backyard doesn’t grow anything but a few weeds. Is there an inexpensive way to get grass or flowers or trees to grow?

A. There is no quick or inexpensive route to good-quality soil. You can purchase topsoil, but beware of inexpensive sources; it might not be all that much better than what you have now. Compare various sources and ask for references; it might well be worth spending extra for good quality.

Or, another option would be to start your vegetable and flower gardening in containers and raised bed planters. You can purchase quality soil mix from garden retailers for those smaller areas. Meanwhile, start a soil improvement program so that you can expand your gardens in years to come. Add a good amount of organic matter, such as compost, animal manure, cover crops or organic mulch materials, each year as the soil is worked. You’ll need to add at least a 2-inch layer of material to make a marked improvement. This translates to about 17 cubic feet of organic matter to cover a 100-square-foot area. Although adding some sand along with the organic matter is acceptable, adding sand alone is not advised. The organic matter offers several advantages that sand does not, including increased water- and nutrient-holding capabilities in addition to improved aeration.

And remember that soil improvement is a program, not just a one-shot deal. You’ll need to continue applications at least once a year for several years to really change the nature of the existing soil.

Q. I planted zucchini seeds last year. They came up and bloomed but produced no fruit. What happened? The previous years, I’d had bumper crops from the seeds. Someone said it needed to be pollinated by bees. I realize the bee population has fallen to one disease or another. Was this the problem? We enjoy zucchini to make bread, eat cooked, etc. I have tomatoes in the same plot and they do OK.

A. It is true that zucchini and other types of squash require bees to pollinate the flowers in order for fruit to be produced. Squash has separate male and female flowers; both types occur on the same plant. The female flowers look like they have miniature squash fruits at the base of the petals; the male flowers produce the pollen, then fall off the plant. Bees are less likely to work the plants during extreme heat or cold. But if no fruit are produced throughout the growing season, then some other culprit is at work. Perhaps bees are in short supply in your area. Sometimes gardeners inadvertently kill bees by applying insect pest controls.

Use more bee-friendly methods of pest control this year, such as hand removal, floating row covers, etc. Plant a variety of flowers of various colors near your garden, to help attract and feed bees. If the lack of bee activity continues this year, you can try to hand-pollinate some of the flowers. Use an artist’s paintbrush to pick up some pollen from the male flowers and then lightly brush the pollen on to the top of the pistil in the female flowers.

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