Horticultural Update is published by Extension Horticulture, Texas Agricultural Extension Service, The Texas A&M University System, College Station, TX. Editor: Edna Smith, Designer: Jill Stavenhagen. Contributing Editors: Drs. Samuel D. Cotner, Vegetables; George F. McEachern, Pecans & Grapes; William C. Welch, Landscape; Douglas F. Welsh, Landscape
Editor September 1997: Douglas F. Welsh, Landscape Horticulturist
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In this issue . . .
Plant of the Month: Jujube
Fall Webworms
Extension Horticulture Publications on the Web
The Natural Killer: Soil Conditioner
Emergency Procedure
Harvest for Highest Quality
Chinaberry Trees
Garden Checklist for October
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FALL WEBWORMS
This article, by Sonal Bhuchard, Master Gardener Intern, Fort Bend County Extension, appeared in "Fort Bend Gardening," July/August/September 1997.
It's that time of year again! The fall webworms have struck! Easily identifiable and detected by their baggy, grey, Halloween-like, ugly webs that entwine the branches of pecan trees, webworms are the most damaging of the gregarious caterpillars, because they can defoliate entire trees. After webworm outbreaks in the late 1980s, many untreated trees in Texas were left without a single leaf on them.
Life Cycle: A mass of buff-colored eggs, covered with a scaly substance, is deposited on the underside of the pecan leaves; these hatch into tiny worms that eat fast and furiously, and weave webs around the branches. Mature webworms grow to about 1.5 inches. The moth is snowy white, and has a wing span of 1.5 inches. The mature webworms fall or migrate to the ground, pupate over winter in the soil, and emerge in early June. A second brood emerges in August. Trees that suffer damage and defoliation by second-generation worms are more susceptible to winter freezes, because they re-foliate late in the season, and fail to go dormant; thus, they may die back in severe temperatures.
Control and Management: With very light infestations, it may be possible to remove the worms by hand and burn them. Under most circumstances, however, an active approach with a BT product, such as Javelin WG, yields good results. Sevin is also effective in controlling webworms, but it has the disadvantage of killing the beneficial insects, which, in turn, causes the aphid population to rise and cause further damage.
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EXTENSION HORTICULTURE PUBLICATIONS ON THE WEB
By Douglas F. Welsh, Ph.D.
Associate Professor and Extension Horticulturist
Aggie Horticulture, the award-winning web page of the Department of Horticultural Sciences at Texas A&M University, is quickly becoming a major source of Extension publications on landscape plants, design and maintenance. In recent months, over a dozen of the most popular Extension Horticulture publications have been put on the internet at the Aggie Horticulture web site. Each publication reads exactly as it does in the "hard copy" found on the shelf at the county Extension office. Most of the publications have been enhanced with beautiful artwork and graphics. And most important, each publication can be printed off of the web at County Extension offices or at home off personal computers connected to the web.
Below is a list of Extension landscape publications now available at the Aggie Horticulture web site:
Water Gardening in Texas
Fertilizing Woody Ornamentals
Proper Pruning Techniques
Protecting Existing Landscape Trees from Construction Damage Due to Grade Changes
Energy-Efficient Fertilization Practices
Lawn Fertilization in Texas
Landscape Water Conservation . . . Xeriscape
Landscaping for Energy Conservation
Timely Tips on Starting Seedlings at Home
Air Layering for Difficult-to-Root Plants
Master Gardener House Plants Guide
Efficient Use of Water in the Garden and Landscape
Don't Bag It--Leaf Management
Seasonal Color . . . Care and Management
Planting a Tree
Planning the Home Landscape
Aggie Horticulture is accessed by logging on to the World Wide Web using browser software such as Netscape Navigator, Mosaic, Internet Explorer, or similar programs, or by using the exciting new WebTV device. The address (URL) is: http://aggie-horticulture.tamu.edu
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THE NATURAL KILLER: SOIL CONDITIONER
This article appeared in "Growing Fall Vegetables and Annuals in Texas," produced by the Texas Agricultural Extension Service, College Station, Texas.
Cereal rye (Elbon) has proven to be the fastest growing, most cold-tolerant annual grass available to home gardeners in Texas. You can plant cereal rye in late fall, and have a thick mat of grass approximately 10 to 15 inches high in late winter. This grass should be shredded with a lawn mower or flexible string trimmer, and tilled into the soil so that decomposition can occur before you plant in the spring. Ideally, shredding and tillage should be done one month before planting to allow for adequate decomposition.
There are many advantages to following this practice of planting cereal rye in your garden. It beautifies the area with greenery. It will add high levels of organic matter to the garden soil. This type of 'green manure' crop decomposes rapidly. As if these benefits were not enough, the roots of cereal rye also serve as a trap-crop for nematodes; once nematodes enter the rye roots, they cannot escape, and are doomed. And, when cereal rye decomposes, it releases organic acids which tend to help reduce the alkalinity of garden soil.
Gardeners should be careful to purchase cereal rye (Elbon) rather than annual rye. Annual rye is used to over-seed lawns , and should not be used in your vegetable garden. In fact, cereal rye has been found to be superior to annual rye for seeding lawns as well.
Cereal rye can be planted by merely seeding directly on top of the garden soil and raking in. Apply seed at the rate of one pound per hundred square feet of garden area, to insure good coverage and adequate growth. Raking to give seed some soil coverage helps. Be sure to water the rye regularly, and fertilize with any type of non-slow fertilizer every three weeks for maximum growth. Remember that the majority of the organic material produced is in the root system rather than the top foliage. This is a case of 'What you don't see is what you actually get!' Always shred the rye before it forms seed heads, since sprouting rye seed in early spring could become a nuisance. There is no danger of rye seeded in the fall becoming a weed problem during the spring, since rye plants cannot withstand hot temperatures, and they will die. Shred rye and till the soil one month before planting so that the massive rye root system will have adequate time to decompose.
Now you know how to give those nematodes what they deserve -- the death sentence.
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EMERGENCY PROCEDURE
This article appeared in "Growing Fall Vegetables and Annuals in Texas," produced by the Texas Agricultural Extension Service, College Station, Texas.
In late fall, the weatherman will give the bad news: a blue norther, which will freeze all tender vegetation, is on the way. If you followed recommended planting schedules, your fall garden should have been producing luscious vegetables for over a month. However, gardeners should prepare to weather the storm! Texas weather is peculiar. Northers blow through for several days, then the weather often clears and warms. The next cold weather may not occur for several weeks. If tender vegetation was protected during the cold snap, you can continue harvesting summer vegetables in winter months.
Only tender, frost-susceptible vegetables need protection. Hopefully, these were planted together, as recommended. Frost-tolerant vegetables can withstand considerable cold.
If tomatoes have been supported by cages secured to prevent blow-down by high winds, these cages can be used as miniature greenhouses. Cover each cage with a plastic bag, and place a light bulb in each covered cage. The burning bulb releases enough heat to prevent plant damage from temperatures as low as 25 degrees F., or colder. Remember to anchor these cages, because if they blow down on a cold night, all efforts are in vain.
Anchored cages can also act as supports for a larger covered structure. For example, where a row of caged tomatoes borders each side of two rows of beans or squash, a greenhouse-type structure can be made by draping a large sheet of polyethylene plastic from the base of one row of cages to the base of the opposite row of cages. Anchor loose ends of plastic with soil or rocks.
As little foliage as possible should come into contact with the plastic, since the contacted foliage will freeze. After danger of frost is past, only one side of the makeshift greenhouse is rolled back. The other remains secured with soil for a quick cover on the next frost alert.
Maybe you don't want to go to all of this trouble. In that case, be prepared to harvest all frost-susceptible vegetables before the first killing frost.
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HARVEST FOR HIGHEST QUALITY
This article appeared in "Growing Fall Vegetables and Annuals in Texas," produced by the Texas Agricultural Extension Service, College Station, Texas.
Many gardeners do not know when to harvest home-grown vegetables. Proper harvesting at the right stage of growth is essential for good yields of high quality vegetables from the fall garden.
Bean, snap - when pods are nearly full size but before seeds begin to show appreciable enlargement.
Beets, as greens - when leaves are 4 to 6 inches long.
Beets, as tops and small beets - when beets are 1 to 1-1/2 inches in diameter.
Beets, as beet roots only - when roots are 1-1/2 to 3 inches in diameter.
Broccoli - when flower heads are firm and fully developed, but before individual flowers start opening; cut 6 to 7 inches below flower head.
Brussels sprouts - when buds along the stem become solid, and thereafter as higher buds become firm. Remove leaves along stem to hasten maturity.
Cabbage - when heads become solid; to prevent splitting of mature heads, twist plants enough to break several roots, and thus reduce water uptake from the soil; excessive water uptake causes splitting.
Carrots - when roots are 3/4 to 1 inch or more in diameter; during cool, dry periods, leave carrots in the ground for later harvests.
Cauliflower - when curds (heads) are 4 to 8 inches in diameter but still compact, white, and smooth; exclude sunlight when curds are 2 to 3 inches across by covering them with an inverted cabbage leaf (this may need replacing once or twice), or by loosely tying the outer cauliflower leaves together above the curd; curds exposed to sunlight rapidly become discolored, rough in appearance, and coarse in texture.
Chard - thin and use small plants when they become 6 to 8 inches tall; thereafter remove only outer, older leaves when 8 to 10 inches long; new leaves continue to grow for a continuous harvest of young, tender chards.
Collard - break off older, lower leaves when they are 8 to 12 inches long; new leaves continue to grow for a continuous harvest.
Kohlrabi - when bulbs (thickened stems) reach 2 to 3 inches in diameter.
Lettuce, leaf forms - when older, outer leaves are 4 to 6 inches long.
Lettuce, heading forms - when heads are moderately firm, and before seed stalks start; take older, outer leaves from either leaf or head lettuce as soon as these leaves are 4 to 6 inches long; new leaves provide a continuous harvest of tender, tasty leaves until excessive cold weather.
Mustard - when older, outer leaves are 6 to 8 inches long; new leaves provide continuous harvest until leaves are strong in flavor and tough in texture from hot weather.
Parsley - when older leaves are 3 to 5 inches long; continue to take older, outer leaves for fresh, tender parsley until heavy frosts in early winter.
Peas, regular varieties - when pods are fully developed but still bright green.
Peas, edible-podded varieties - when pods are fully developed but before seeds are more than one-half full size, if pods are to be eaten; harvest when seeds are fully developed but still fresh and green, if pods are to be discarded.
Potato - when tubers are full size and have a firm skin; new potato tubers may be dug at any size, but generally are not harvested before the tubers are 1-1/4 to 1-1/2 inches in diameter.
Radish - when roots are 3/4 to 1-1/2 inches in diameter, thin radishes to 1 inch between plants, to insure rapid, uniform growth and crisp roots.
Spinach - when larger leaves are 4 to 6 inches long; pull larger whole plants or harvest older leaves, and allow new growth to develop.
Squash, winter types - when fruits are full size, the rind is firm and glossy, and the bottom of the fruit (portion touching the soil) is cream to orange colored; light frost will not damage mature fruits.
Sweet potato - late in the fall, but before the first early frost; lift to avoid cuts, bruises, and broken roots; cure in a warm, well-ventilated place for 2 to 3 weeks, and store in a cool, dry place.
Turnip - when roots are 1-1/2 to 3 inches in diameter, but before heavy frosts in the fall.
This article appeared in Growing Fall Vegetables and Annuals in Texas, produced by the Texas Agricultural Extension Service, College Station, Texas.
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CHINABERRY TREES
By Greg Grant, Cherokee County Horticulturist
Texas Agricultural Extension Service
In the 1987 book "Gardening for Love," the late Elizabeth Lawrence talks of Chinaberries . . .
"Chinaberries are hardy as far north as Virginia, and have been planted in the South since Colonial times. At Monticello, Thomas Jefferson planted a grove on the southwest side at the roundabout, and it also grew in the gardens of Williamsburg. Before the Civil War, it had become as typical of the South as lilacs are of New England. Longfellow wrote in Evangeline of the houses of planters shaded by China trees, and Harriet Beecher Stowe described them in detail. When Uncle Tom arrived at Simon Legree's plantation, "The wagon rolled up a weedy gravel walk, under a noble avenue of China trees, whose graceful forms and ever-springing foliage seemed to be the only things that neglect could not daunt or alter -- like noble spirits, so deeply rooted in goodness as to flourish and grow stronger amid discouragement and decay." And when Legree rode around the quarters on a moonlit night, "the shadows of the graceful China trees lay minutely penciled on the turf below, and there was that transparent stillness in the air which it seemed almost unholy to disturb."
Often frowned upon by today's horticulturists due to its weak wood and relatively short life span, this stately member of the mahogany family used to be a universal item in landscapes of the South. According to the 1993 Hillier Manual of Trees and Shrubs, it has been cultivated in England since the sixteenth century. In his diary, George Washington mentions planting the Pride of China tree at Mount Vernon, and Thomas Jefferson makes numerous references in his garden diary to the Pride of China trees cultivated at Monticello.
The Chinaberry was frequently used as a street tree. Loudon's Encyclopedia of Gardening (London, 1839), mentioning the garden of Lewis LeConte, says, "The village of Riceborough . . . is very picturesque. Most of the houses have verandas; and it is observed, both by Captain Hall and Mr. Stuart, that the pride of India [Chinaberry], the Melia Azedarach, is planted along the streets, as well as in those of most of the southern towns, particularly Charleston and Savannah." In a letter to the editor of the Natchez Daily Courier on October 24, 1854, Thomas Affleck was among the first horticulturists to bash the ever-so-common Chinaberry with the written word: "The perpetually recurring Pride of China tree, beautiful though it be, to the exclusion of the scores of magnificent trees, native and introduced, is, to say the least of it, in very bad taste. It is a filthy tree, too, about a yard, when compared with many others." He goes on to chastise the city by saying, "Suppose that, instead of the China tree, your streets and pleasant Bluff promenade had been lined and shaded with . . . oaks!"
The most sought after form of this tree was the Texas umbrella China (M. azedarach umbraculiformis). Bailey's 1916 Standard Encyclopedia of Horticulture describes it as such: "Leaflets are less broad than in M. azedarach, and the branches erect, and, in a manner, radiating from the trunk, the drooping foliage giving the tree the appearance of a giant umbrella . . . The first tree that came to notice is said to have been found near the battlefield of San Jacinto, Texas, but there is no record of its introduction there. If the flowers are cross-pollinated with the common sort, the percentage of seedlings which reproduce the exact umbrella shape seldom varies; hence, it is supposed by some to be a distinct species."
I'm not sure when the umbrella form was introduced. Langdon Nurseries of Alabama lists it in the 1881-82 catalog, mentioning that it originated in Texas. The 1888 catalog of Mission Valley Nursery near Victoria, Texas, says it is "Too well known to require description . . . " It is not, however, listed in Thomas Affleck's 1851-52 Southern Nurseries Catalog from Washington, Mississippi. The 1905 Alvin Nursery catalog says the Texas umbrella is the "Finest shade tree known. With care, the tree will make a spread of fifteen feet in one year. A most beautiful shaped tree, making a very compact head without pruning." The umbrella China was eventually offered by most southern nurseries and probably every early Texas nursery.
I remember as a child, the umbrella Chinas at my grandparents' home in Shelby County, Texas. There was a huge one in the back yard where the corn shucking always took place. It had an open spot in the center where the chickens nested and I would perch in hiding. I also remember my grandfather, Elroy Emanis, topping the young ones to make the umbrella shape even tighter. This severe topping or pollarding was, and still is, a common practice on Chinaberries in the rural South. Before he died, he planted some Chinaberries that turned out not to be umbrella chinas, and he wasn't pleased.
Even if you don't like Chinaberries, it is hard not to enjoy the fragrant lavender spring blossoms. But you might as well learn to like them, because we probably couldn't get rid of them if we wanted to!
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GARDEN CHECKLIST FOR OCTOBER
Dr. William C. Welch, Landscape Horticulturist
Texas A&M University, College Station, Texas
October through November is an excellent time to purchase bulbs while there is still a good selection. Bulbs can be planted at any time, except tulips and hyacinths.
Refrigerate tulip and hyacinth bulbs until mid to late December before planting. The lower part of the refrigerator is best. Do not leave bulbs in airtight plastic bags during refrigerator storage.
Plant bulbs in well-prepared beds. The base of the bulb should be at a depth that is three times the diameter of the bulb. In sandy soil, set bulbs slightly deeper; in clay soils, slightly shallower.
Start collecting leaves for composting. Be sure to have enough soil on hand to cover each 6-inch layer of leaves with several inches of soil. Add about 1 pound of a complete lawn or garden fertilizer to each leaf layer to provide the necessary nitrogen for decomposition. Thoroughly wet the leaf layer before adding soil.
Check your nursery or garden center for plants of snapdragons, pinks, sweet williams, poppies, and calendulas. Planted now, they will usually provide a riot of spring color.
Keep Christmas cacti in a sunny spot with nighttime temperatures below 65 degrees F; buds drop if nighttime temperatures rise above 70 degrees F, or if the plants become excessively dry. To initiate flower buds, Christmas cacti should be kept in total darkness from 5 PM until 8 AM for about 30 days in October.
If you have saved seed from your favorite plants, first air-dry them, and then place in an airtight container and refrigerate. Carefully label each packet. Remember, plants grown from hybrid plant seed seldom resemble the parent plant.
Prepare planting beds for pansies as soon as they are available at garden centers, and the night temperatures begin to cool. Pansies need well-drained soil and at least a half day of sun. It is best to use started plants, as seed is difficult to handle.
If you wish to save caladium tubers for another year, dig in late October and allow them to dry in a well ventilated but shaded area. After 7 to 10 days, remove the leaves and dirt; then, store in dry peat moss, vermiculite, or similar material. Pack so that the tubers do not touch each other, and dust with an all-purpose fungicide. Store the container in an area where temperatures won't drop below 50 degrees F.
If twig girdlers have infested your trees, and many twigs and branches are dropping, make sure these are collected and destroyed, since the eggs are deposited in that portion of the branch that drops to the ground.
There is still time to divide and reset perennials such as phlox, violets, iris, day lilies, and shasta daisies.
October is a good time to reduce the potential for insects and disease in next year's garden. Clean up the garden, removing all annuals that have completed their life cycle. Remove the tops of all herbaceous perennials when they finish flowering, or as soon as frost kills the leaves.
Holly plants with a heavy set of fruit often suffer from a fertilizer deficiency. Applying a complete fertilizer late in October can be helpful, and will provide a head start next spring.
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