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September Plant of the Month: Acalypha Wilkesiana, Copperleaf
Grapes: Vine Symptoms for Pierce's Disease
Value of Trees in the Landscape: Yes, Money Grows on Trees
Marigolds: "Mari-Mums": A Breakthrough in Fall Beauty
Cole Crops for Texas Gardens
Chemical Bans: "To be REALLY Safe, Let's Ban Everything"
Oktober Gartenfest Symposium
Garden Checklist for September
As noted last month, the paper form of ‘Lawn and Garden Update' that we have been sending out monthly has been replaced by this Web edition.
‘Horticulture Update' is designed as a source of information for County Extension Agents and Specialists to utilize in local news releases and as part of their educational programs across Texas, but will also appeal to gardeners and plant-lovers of all kinds, especially those interested in growing plants under the tough conditions of Texas and the Southern United States. Our information is oriented for Texas gardeners and Texas conditions.
Each issue includes a monthly checklist for suggested garden activities along with articles on gardening topics and profiles of plants especially suitable for Texas and the South. Another feature of the publication is information about forthcoming educational opportunities sponsored by the Texas Agricultural Extension Service.
Dr. William C. Welch and I share editorial responsibilities for the newsletter. Articles from County Extension Agents (Horticulture) and specialists in related disciplines are welcome and encouraged. Bill and I are both Extension Horticulturists in the Department of Horticultural Sciences at Texas A&M University.
Photos in this issue are courtesy of Dr. William C. Welch and Cynthia W. Mueller.
Acalypha Wilkesiana Copperleaf
By Dr. William C. Welch
Landscape Horticulturist
Although a perennial or evergreen in milder climates, copperleaf is normally used as an annual in Texas. Few flowering plants can compete with its spectacular color from September until frost. Numerous cultivars are available and differ in leaf size, shape and coloration.
Leaves are up to eight inches long and may be bronzy green mottled with shades of red, crimson or purple. In a warm sheltered spot copperleaf may reach 6 feet or more although 3 to 4 feet is more typical.
The many colored strains of Acalypha Wilkesiana are much planted in south Florida and the American tropics. They are native to the South Pacific islands where they occasionally reach 15 feet in height.
By Dr. George Ray McEachern
Professor and Extension Horticulturist
The best tests for Pierce's Disease (PD) of grape vines are the classic symptoms on the vine; leaf burn, leaf petiole retention, green islands at shoot nodes, cluster raisining while most clusters on the same vine are normal, and vine death.
The ELISA or PCR tests are good only if the test results are positive. If the results are negative, the sample could be a false negative, and the sample is actually positive. Growers should not wait for a positive lab test before attempting to prune PD out of the vines, symptoms are enough.
The best test is vine symptoms. Late July, August and September are the best times to observe the symptoms. If at least three of the five symptoms are identified, and if the vines are growing in a PD zone, the vines need to be marked with a flag or paint, so they can be pruned back to the trunk or above the graft union during winter pruning.
Leaf Burn is non-uniform slow marginal necrosis of the leaf blade. The green leaf blade will turn brown at one or two points on the edge of the leaf. This is different from brown all the way around the leaf edge, as with drought or salt burn. A second leaf sign of PD is a yellow front between the brown and green on white grape varieties, and a maroon front for reds.
Petiole Retention occurs when leaf blades on a shoot fall off with a number of petioles attached to the shoot. Normally a leaf falls off with the petiole attached to the leaf blade and not the shoot.
Green Nodes as islands on a brown shoot are a symptom of PD. Normally the shoot internodes and nodes mature at the same speed, thus turning from green to brown together. However, with PD there can be distinctively green and brown areas in the internode area.
Limited Cluster Raisining occurs when one or two clusters on a vine will dehydrate and turn black while all of the berries and other clusters ripen normally.
Vine Death can occur from PD when dormant canes appear normal at winter pruning. A near death infected vine can have limited or no bud break in the spring.
Symptomatic vines can occur as individuals or in a group, they can be at the perimeter or within the vineyard. Young and old vines can have PD. Very few grape varieties are tolerant to PD.
Yes, Money Grows on Trees
By David S. Jones
There is no simple method for determining how much a tree is worth. If you have watered, fertilized and pruned the tree since it was a mere sapling, you may figure the tree is quite valuable. If it's a naturally occurring tree, you may have less attachment.
Well-maintained, mature, healthy trees can increase the value of your property by as much as 25 percent, depending on their size, species and location. Check the real estate classifieds, and see how many ads mention a "well-landscaped yard," "shaded patio," "great view of trees" or some other tree-related description.
A tree can be valued from $300 (for firewood) to $10,000 for an appraised tree with maximum benefits. A homeowner might value a tree as priceless because of special memories attached to it.
Trees have a monetary value that can be calculated and often recovered when they are damaged or lost. A knowledgeable arborist is the best person to perform an appraisal of your trees. You should document their value with photos and a professional landscape appraisal if you want maximum proof for insurance and tax purposes.
The replacement method is one of two main methods to value trees. Trees are measured at breast height or 4-feet above ground. With this method, replacement cost is the average cost local nurseries charge for the same size and species tree. The cost may include labor for removing the old tree and planting a new one. Often, however, it's not possible to replace mature trees. Special "tree spades" can move trees as tall as 35 feet, and larger ones can be craned on to a flatbed truck, but now we're talking some big money.
The second technique for determining tree value is called the basic formula method. Value is determined by multiplying the number of square inches in a trunk cross section 4 feet above ground. Adjustments are made for the species, condition and location. Regardless of the method used, it takes technical competence and experience to determine a tree's worth.
Physical condition affects a tree's value. Parts deformed by crowding, storm drainage, fire, insect damage, disease or other causes deduct from its worth. Plant location, especially when it is near buildings, utility lines or other plants, can be a detriment. Trees in planned landscapes often have higher appraised values than those growing wild.
Trees can be worth more for the shade they provide. That's because they help reduce temperatures in and around buildings. According to a technical guide from the USDA Forest Service, three well-placed trees can cut air-conditioning costs by 10 to 15 percent. According to www.treefolks.org, properly placed shade trees can reduce energy consumption by as much as 30 percent. If storm water runoff is a problem in your area, you should be aware that a tree with a modest canopy could reduce runoff by 12 percent to the value of your property, according to Michigan State University. With little or no maintenance, trees usually increase in value from 5 to 10 percent each year.
When trees are appraised, the Guide for Plant Appraisal is cited often. Written by the Council of Tree and Landscape Appraisers, it's the reference professionals use to properly determine factors affecting the value of plants. The April 2000 edition is $125 from the
P O Box 3129
Champaign, Illinois 61826
or
A Breakthrough in Fall Beauty
By Kim Elsom
Master Gardener, Lamar County, Texas
It's mid-August, hotter than a two-dollar pistol and both you and your landscape plants have the late-summer doldrums. This means it is much too early to plant pansies because they will scorch badly in the heat. But, Old Man Summer has hammered most of the earlier planted annuals to a frazzle. Is there a shining knight that can rescue you from these doldrums? You bet there is and it's called a Mari-mum.
The name Mari-mum is derived from a combination of the terms marigold and chrysanthemum and denotes large-flowered American marigolds which possess a similar flower form and are used as a fall crop like chrysanthemums. The marigolds which best fit this concept are hybrids characterized by earlier blooming, larger flowers and high levels of uniformity.
Their Attributes Abound
Several years of testing by Texas Agricultural Extension Service horticulturists in both south and north-central Texas have revealed many desirable attributes exhibited by Mari-mums. For example, they are very low maintenance for a flowering annual. They are extremely easy to grow, almost foolproof when planted in a well-drained soil in full sun. They produce more blossoms and retain better blossom color as a fall crop and they possess tremendous visual impact, even at a distance.
When compared to fall-planted chrysanthemums, Mari-mums will bloom 2-3 times longer. Their open blossoms are more resistant to wind and rain and are less expensive to produce which gives you more bang for your gardening buck.
Spider Mites Not A Problem
At this point many of you are thinking how beautiful Mari-mums will be as a fall crop but you're worried that spider mites, the arch enemy of marigolds, will make their ugly presence known. Spider mites love hot weather but their rate of reproduction is greatly reduced by cool fall temperatures. By first removing any mite-infested plants from the flower bed and then planting fresh marigold transplants in mid-August or early September, you can avoid significant mite injury, all without use of pesticides.
Mari-Mum At A Glance
Transplant in mid-August to early September for the longest period of spectacular bloom. Purchase transplants with foliage only or in bud, but not in full bloom. Plant in full sun with good drainage. Water thoroughly at planting. For the first week after planting, new transplants may need to be watered almost daily. Thereafter, water only when the top inch of soil is dry.
Recommended Cultivars include ‘Discovery Yellow' and ‘Discovery Orange,' dwarf plants 8-10 inches in height, and ‘Voyager Yellow,' a somewhat larger cultivar at 24-26 inches in height.
By Cynthia W. Mueller
Master Gardener, Galveston County
Fall and winter in Texas are ideal for best production of cole crops, which include cabbage, turnips, kale, mustard greens, broccoli, cauliflower and specialty Chinese varieties. In many areas such as South or Central Texas, these plants ignore frosts and light freezes and are only ‘done in' by more severe winter weather conditions. Cole crops often last through the entire season until spring is finished.
Buying ready-grown transplants is the easiest solution for a very small garden. For larger areas, grow your own transplants, except for vigorous varieties such as mustard greens or turnips, which may be direct-seeded outside. Check for optimal planting dates with the local County Extension Office or with the planting calendar offered in the PlantAnswers section of the Aggie-Hort Web. It is important to purchase good seed from a reputable source and sow according to directions in containers. Thin when necessary, and keep a watchful eye out for insect problems such as aphids, and for cabbage loopers. Fertilize occasionally with a light solution of water-based fertilizer. As soon as the weather has cooled, set transplants outside in well-prepared garden soil. Maintain good watering, cultivating and fertilizing routines. Keep dead leaves cleared away to discourage pillbugs, crickets and diseases such as downy mildew.
When planning the fall garden, group the cole crops you intend to plant into three categories so that as the earliest maturing plants are taken out, something else may be planted instead. Mustard, turnips and turnip greens are considered ‘quick producers,' taking from 30 to 60 days to mature. Broccoli, cabbage, Chinese specialty greens (Bok Choy, Tat Soi, etc.) are ‘moderately quick' and provide food for the table in 60 to 80 days. ‘Slow producers' taking 80 days or more include Brussels sprouts, cabbage and cauliflower.
Cole crops are able to take a little more shade than many vegetables. Parts of your garden that might have been too shady during the summer could now be considered for planting now that many trees and shrubs are losing their leaves. Brussels sprouts, cabbage, collard, kale, mustard and turnips all tolerate partial shade.
Ornamental, frilly mustards, colorful kale, and red or green cabbage plants may be interspersed in flower beds to add contrast. Harvest outer leaves throughout the season as garnish or stir-fry ingredients while leaving the rest of the plant for its decorative effect.
By Dr. Elizabeth M. Whelan
President and Science Advocate for the
American Council on Science and Health (ACSH)
While Americans blithely go about their business, an insidious and irrational flight from technology is taking place, all in the name of 'public health'. In recent weeks, two safe and useful products have been taken away from consumers, despite the conclusions that the approved use of these products is safe. To make matters worse, some manufacturers of these rejected technologies are joining forces with some extreme environmentalist groups and the U.S. Environmental Protection Agency (EPA) to protect us from hazards that do not exist.
Recently, ACSH criticized 3M's withdrawal (prompted by pressure from the EPA) of its unique fabric protector Scotchgard. The product will soon disappear from the supermarket shelves, not because there is any evidence it is unsafe, but because trace levels of some of the product's chemical components have been persistent in human blood samples and in the environment. These trace levels of chemicals in the blood have not been deemed harmful, but their mere detection was enough to be fatal to Scotchgard.
The EPA has also announced its ban of Dursban, one of the most common ingredients in home, lawn, and garden bug killers. This compound is found in familiar household pesticide sprays such as Raid and Black Flag roach and ant killer. EPA administrator Carol Browner defends her decision to ban this useful product by claiming that Dursban causes damage in the brains of newborn rats. She further argues that both children and adults have been harmed from the use of these products. These sprays can indeed, when misused, be toxic, and misuse and accidental ingestion of the products could cause serious health hazards. Yet, Ms. Browner presents no evidence that the approved and intended use of Dursban products poses any health problems at all.
Thus, the 3M Scotchgard episode and Dursban sequel illustrate an emerging -- and unscientific -- code for 'protecting public health', as follows.
#1. Ban the product if you can find traces of any chemical components persisting in the body or the environment. Scientists know that the ability to merely measure the presence of a chemical that is potentially harmful does not indicate that human health is in jeopardy. Furthermore, it is well known that human blood contains traces of nearly all the myriad natural and synthetic chemicals to which we are exposed daily.
#2. If it causes health problems in rodents, ban it. Yet repeated laboratory-animal studies using extremely high levels of naturally occurring chemicals (in food, water, and air) can cause toxic effects, cancer, and reproductive damage. For example, the naturally-occurring chemicals hydrazines, found in mushrooms, are carcinogenic in rodents. Arsenic and solanine, natural components of potatoes, can be highly toxic to humans and animals in high doses, but are harmless in the trace levels found in spuds.
#3. If the product is abused or misused, ban it, even for its rational, approved use. Yet common pharmaceuticals, cosmetics, cleaning agents -- and even table salt -- can cause injury and death if misused or accidentally ingested. In the case of a small child, even small amounts of such ingested material can pose a grave risk. Are we pursuing such a degree of safety in our society that we are willing to discard any and all useful technology where no valid evidence of a health threat with intended use exists? And what negative consequences might we face from the purging of these allegedly hazardous materials?
That 'household hint' guru, Heloise, recently appeared on the Today Show, suggesting primitive ways of protecting our clothes from stains, now that Scotchgard will be gone. But what her comments made clear is that there are no good alternatives to Scotchgard available, and that means higher costs for all of us to replace blighted clothes and furniture. And with Dursban gone (most likely to be joined in the graveyard of chemicals by pesticides with similar properties), we have lost even more of our tools in fighting off the asthma-inducing effects of cockroaches and other pests.
The most troubling aspect of this insidious threat is that consumers seem unaware that we are on a slippery slope, with almost any useful and safe consumer product now vulnerable to strident cries to 'be safe rather than sorry' to 'protect the children'. And, to make matters worse, some manufacturers seem to be willing to fold up their tents and move on rather than stand up for the science-based conviction that their products are safe.
Texas Gardens: Something Old, Something New
October 27-28, 2000
Round Top, Texas
For information about Oktober Gartenfest 2000, click on the following: 2000 Oktober Gartenfest
To print out a registration form, click on the following: Registration Form
For information about overnight accommodations in the Round Top area, contact Gloria Jaster at the UT Winedale Center (979) 278-3530 or fax (979) 278-3531.
By Dr. William C. Welch
Professor and Landscape Horticulturist
- Rejuvenate heat stressed geraniums and begonias for the fall season by lightly pruning, fertilizing, and watering.
- Caladiums require plenty of water at this time of year if they are to remain lush and attractive until fall. Fertilize with ammonium sulfate at the rate of l/3 to l/2 pound per 100 square feet of bed area, and water thoroughly.
- Don't allow plants with green fruit or berries to suffer from lack of moisture. Hollies will frequently drop their fruit under drought conditions.
- Remove weak, unproductive growth from crape myrtles and roses to stimulate new growth for all beauty.
- Prune out dead or diseased wood from trees and shrubs. Hold off on major pruning until midwinter. Pruning now may stimulate tender growth prior to frost.
- Sow seeds of snapdragons, pinks, pansies, and other winter flowers in flats for planting outside during mid to late fall.
- Prepare the beds for spring flowering bulbs as soon as possible. It's important to cultivate the soil and add generous amounts of organic matter to improve the water drainage. Bulbs will rot without proper drainage.
- Divide spring flowering perennials such as irises, shasta and oxeye daisies, gaillardias, canna lilies, daylilies, violets, liriopes, and ajugas.
- Fertilize and groom verbenas, perennial salvias and lantanas by lightly pruning and removing non-vigorous wood, to stimulate a long and productive fall season.
- Christmas cacti can be made to flower by supplying 12 hours of uninterrupted darkness and cool nights (55 degrees F) for a month starting in mid-October. Keep plants on the dry side for a month prior to the treatment.
- As they begin to dry naturally on the plants, cut ornamental gourds and store in a well ventilated, dry place for several weeks prior to use.
Douglas F. Welsh, September Editor
Cynthia Mueller, Editorial Assistant
Jill Stavenhagen, Web Site Design
Extension Horticulture
Texas A&M University
HFSB 225
College Station, Texas 77843-2134
(979) 845-5341
fax: (979) 845-8906
http://aggie-horticulture.tamu.edu/