Pelargonic acid Do you know where I could obtain a product with pelargonic acid?-via the internet
Two suppliers are Monterey Chemical (www.montereychemical.com; (559) 449-2100), which supplies a product called Quik; and Mycogen/Dow AgroSciences (www.dowagro.com; (800) 253-3033), which produces Scythe herbicide. Other brands are available in garden centers and retail outlets, though these are packaged and marketed primarily for retail consumers.
Shear agony Sometimes when I prune using loppers, the nut gradually tightens until I can't operate the shears anymore. I have to stop and loosen the nut. They seem to do this on their own during use. Why?-California
This can be hard to pinpoint. Bob Denman, a retail tool supplier as well as a product development consultant for Corona Clipper Co., notes several factors that interfere with the normal movement of the cutting-head parts could cause such a problem. Sap buildup, grit, rust or metal burs, especially on the bearing surfaces or threads of the pivot bolt, are possibilities. Designs improvements in recent years should reduce this type of problem, so Denman's guess is that you may be using older shears.
A likely way to solve your problem is to dismantle the cutting head and clean off any grit, sap, rust, metal burs or other contaminants. Be sure you clean all parts, including threads. Then lubricate the shears and reassemble to the proper tightness. If the threaded end of the bolt protrudes noticeably beyond the nut, you might be missing a washer, which is another factor that could result in the problem you describe.
It may be necessary to replace the bolt and nut if they're damaged. Suppliers in some agricultural regions often stock replacement parts, whereas most nurseries and hardware stores do not. If you can't find parts locally, contact the manufacturer directly. Parts generally are inexpensive.
Denman notes that most good-quality pruning shears (unlike the cheaply made "knock-offs," especially imports, which retailers often stock) should last many years if maintained properly. The trouble is that most people, including landscape professionals, rarely take good care of pruning tools. According to Denman, most pruning shears he receives for repair or replacement can be restored simply by cleaning, lubing, sharpening and reassembling them correctly. Of course, it makes more sense to simply take good care of them from the start. Good tool maintenance includes:
* Frequent sharpening with a proper-size diamond file-every day during normal (intermittent) use, every hour or two during constant pruning. * Frequent cleaning and lubrication. Denman suggests using a particular synthetic oil found in several products. Corona carries its own label (CLP), but it is the same ingredient found in BreakFree CLP (for oiling firearms) and Harley Davidson chain lubricant. WD-40 is not a good lubricant for this purpose. * Correct tightening. With most recently manufactured shears, you simply need to tighten the nut until it freezes the shears, then back off just enough for the head to operate freely. * Oiling of wooden handles. Annual treatments with generous amounts of tung or linseed oil prevent drying and brittleness.
Deer-resistant plants Several years ago you ran an article about deer in the landscape. The article included a list of plant species resistant to deer. How can I find such a list?-Via the internet
The article you refer to was "Put deer on a diet," by Jeff Jackson (in the April 1992 issue of Grounds Maintenance). The list that appeared in the article is too long to reprint here. As an alternative to searching for this article, you have some other options. Check with your nearest extension office. They are likely to have something you can use. You also should try an internet search using "deer resistant plants" as the search term. You'll find plenty of information.
It's helpful to use a list compiled for your region, which is why your local extension office (or perhaps a local nursery) should be especially useful. Lists tailored to regions other than your own may be full of plant species not suitable for your area or, conversely, may omit many choices (for hardiness reasons) that could be used in your locale.
Keep in mind that when deer are numerous or hungry enough, even so-called deer-resistant plants can become deer food.
Many state and local governments have imposed yard-waste bans. Of course, yard waste hasn't gone away, which means that if you're responsible for collecting and disposing of clients' leaves, the annual deluge of foliage may put you in a tough spot.
Some communities have composting programs, which can be successful. But such options are not always available. Is there another alternative? One possibility is to treat leaves as you would turf clippings-mulch them and leave them on the ground. The question is "What will this do to turf (and the soil in which it grows)?" A couple of studies in recent years have helped clarify this.
One, conducted by Cornell University researchers, looked at Kentucky bluegrass and its response to red oak and Norway maple leaves, layered 4 to 5 inches thick, mulched with a mulching mower and left in place.
Spanning 3 years, the study examined clipping yield, visual quality, thatch development, soil pH, soil organic matter and soil-available phosphorus, potassium, calcium and magnesium. The researchers found no significant difference between the turf with mulched leaves and turf that received no such treatment, indicating that mulching leaves and leaving them in place on turf can be a viable method of disposing of leaves without harming turf.
In related work, researchers at Rutgers University looked at how leaves affected farmland after soil incorporation. The Rutgers investigators did not look specifically at turf or landscapes, but their work clearly has implications for these settings.
The Rutgers researchers analyzed the nutritional content of leaves. The dry leaves they evaluated averaged 1.0 percent nitrogen, 0.1 percent phosphorus and 0.38 percent potassium. However, after incorporation, the leaves caused a temporary nitrogen deficiency in plants grown in the leaf-amended soil. This was not surprising considering the high carbon-to-nitrogen ratio of the leaves (50:1). To compensate, the researchers recommend adding supplemental nitrogen for crops growing in leaf-amended soil.
Other effects the Rutgers researchers observed with leaf-amended soil were greater moisture retention, as well as a somewhat higher level of weed infection (perhaps due to the higher soil-moisture level or herbicide tie-up). However, no serious problems occurred, and crop yields on the treated land actually increased compared with untreated land.
More research is needed, especially on different turfgrass species, to better understand the effects of leaf disposal by mulching or soil incorporation. However, the studies strongly suggest that these can be viable disposal methods with few, if any, serious drawbacks. In the coming years, this is likely to become even more important as fewer landfills accept yard waste.
Pollen's ability to cause allergic reactions varies by plant species. This fact has enabled people to predict, based on bloom times, when allergies might be most severe. However, a misconception many people share is that when offending plants are in bloom, you literally cannot get far enough away.
The fact is that researchers now understand that in most cases, 99 percent or more of pollen travels no more than 30 feet from its source, according to Tom Ogren, author of Allergy-Free Gardening (to be published this spring by Ten Speed Press, Berkeley, Calif.). Considering this, it's apparent that the kinds of plants growing in landscapes (particularly one's own) do make a difference. Ogren's book and a similar work, Allergy Free Living by Scott Seargeant (Seargeant Publishing Co., Visalia, Calif.) contain extensive lists of low-allergen species, providing landscape designers with the tools to design allergy-free landscapes.
Ogren's work gives this story a new twist (a fairly obvious one, in retrospect). More than just the species of plant affects allergies. The sex of the plant also matters. For those of you not botanically inclined, some plants are monoecious, meaning that both sexes are present on each plant. However, many are dioecious, with distinct male and female plants. Because male flowers are the ones that produce pollen, a pollen-free plant would, of course, be female.
Low pollen production has not been high on the list of characteristics that plant breeders seek. On the contrary, female plants have been considered less desirable in the landscape because they produce messy fruit and seeds. In the ongoing drive toward lower-maintenance landscapes, growers have produced myriad selections of so-called "fruitless" plants-fruitless mulberry, fruitless ginkos, etc. Many people are unaware that these are not distinct varieties in the traditional sense. They are simply males. Fruitless selections have become so popular that, according to Ogren, in some towns virtually no females of certain species are present.
Ogren also began to notice that many of the most allergenic plants happen to be dioecious. Thus, with the propagation of fruitless selections (which, for the most part, are necessarily dioecious), we have inadvertently been increasing dramatically our exposure to allergenic pollen. While fruit and seeds can be a serious nuisance, the price of eliminating the mess may now be measured in terms of health-not a favorable tradeoff.
Noting that plants vary and are not simply "good" or "bad" when it comes to allergies, Ogren has developed a scale of 1 to 10 (which he calls "OPALS," for "Ogren's Plant Allergy Scale") to define plants' allergenic potential (1 being least allergenic). His book rates more than 5,000 plants according to this scale.
Ogren notes that the U.S. Department of Agriculture is combining its urban species biomass data (an analysis of plant species composition in many U.S. cities) with OPALS to rank cities by their allergy potential. Thus, people who suffer from severe allergies to pollen may have a way to evaluate cities according to their allergy potential.
Local governments are getting in on the act, too. Ogren, who is working with Albuquerque, N.M., on a plant-allergy ordinance, notes that we can expect to see many similar local regulations in the future. The Albuquerque ordinance, still in the formative stages, may serve as a model for other localities. "Like it or not," says Ogren, "this is about to happen and a whole lot sooner than people in the trades realize."
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