 |
 |
 |
 |
||
 |
 |
 |
|||
|
|
|
|
|
||
|
|
|
|||
 |
|
body |
September is here, and after the summer we've had, overseeding or establishing new turf may be the answer to the popular question: "What should I do about the lawn?" question. Beyond deciding whether to reseed or not, anyone with tall fescue or Kentucky bluegrass lawns should plan to fertilize and cultivate this time of year.
September is an ideal time to aerate and fertilize cool-season lawns. And, believe me, many lawns need it. Cool-season grasses are coming out of their summer doldrums and beginning to grow more vigorously as days shorten and temperatures moderate, especially at night. Cool-season grasses naturally thicken up in the fall by forming new shoots at the base of existing plants. Bluegrass re-establishes itself, spreading by underground stems called rhizomes.
Two common aeration methods are power-raking and core-aerating. Power-raking is primarily a thatch-control operation. It can damage turf excessively if not done carefully. For mostly fescue lawns or lawns with « inch of thatch or less, I don't recommend power-raking. Thatch is a springy layer of light-brown organic matter that looks something like peat moss and is located above the soil but below the grass foliage.
Core-aeration is a much better practice for most lawns. By removing cores of soil, core-aeration relieves compaction, hastens thatch decomposition and improves water, nutrient and oxygen movement into the soil. Perform this operation when the soil is just moist enough to crumble easily when worked between the fingers. Make enough passes so that holes are spaced about two to three inches apart. Ideally, the holes should penetrate 2 « to three inches deep. Cores can be left on the lawn to decompose naturally. (This usually takes 2 or 3 weeks, depending on soil type.) They can also be broken up with a vertical mower set just low enough to nick the cores, and then dragging them with a section of chain-link fence or a steel door mat. This creates a mixture of soil and thatch that is good for the lawn.
If your lawn has been severely damaged over the summer you may want to start over. Soil aeration is just as important in this case and best achieved with a rototiller, which not only loosens the earth but also dislodges weeds and other dead or dormant plant material. If you decide to till, be sure to water ahead of time to moisten the hard, summer-baked soil. Once you've tilled, rake to get rid of clumpy plant debris, and roll to smooth the surface. Then fertilize and seed.
To fertilize in September, apply 1 pound of actual nitrogen per 1,000 square feet. Aerate first so it is easier for the fertilizer to work into the soil. Most of the nitrogen should come from a quick-release source at this time. Trust me, the turf will use it. It's been fasting all summer. Most fertilizers sold in garden centers and department stores contain either quick-release nitrogen or a mixture of quick- and slow-release, but many of these mixed products are predominantly quick-release. In any case, they can be used effectively for your fall applications. (MF)
Christmas Cactus (Schlumbergera bridgesii) and Thanksgiving Cactus (Schlumbergera truncata) are popular flowering holiday plants. Both are epiphytes native to the jungles of South America. Epiphytic plants grow on other plants and use them for support but not for nutrients. Though these cacti are different species, they will hybridize and produce varying stem shapes. Christmas cactus normally has smooth stem segments. Thanksgiving Cactus has hook-like appendages on each segment.
Flowering will not occur unless induced by temperature and/or light treatment. If the temperature is held at 50 to 55 degrees F, flowering will occur regardless of day length. But flowering usually is not uniform. Temperatures below 50 degrees F prevent flowering. Flowers can also be generated by nights greater than 12 hours long and temperatures between 59 and 69 degrees. Twenty-five consecutive long nights is enough for flower initiation. It takes an additional nine to 10 weeks for flowers to complete development and bloom.
Both of these cacti like bright indirect light. Too much sun may cause leaves to turn yellow. Common household temperatures are fine. Soil should be kept constantly moist but not waterlogged. These plants seem to flower best if kept a little pot bound. If you need to repot, try waiting until spring. (WU)
If you have saved last year's poinsettia and want it to flower again this year, you must follow certain procedures. Poinsettia's are known as "short-day" plants. Growers found out long ago that poinsettias can be brought into bloom if they are given short days and long nights. Originally, it was thought that short-day plants needed a short duration of daylight in order to flower. Now we know that flower formation is actually triggered by long periods of uninterrupted darkness. For poinsettia, at least 12 hours of each 24 must be uninterrupted dark. Night temperature also has an effect and should be below 70 degrees F with 60 to 65 degrees F preferred.
During the day, place the plants in the sunniest location of the house. This high level of light is needed for the plants to have the energy required for good bract coloration. Day temperatures should range between 65 and 75 degrees F.
Providing uninterrupted darkness can be a problem for gardeners unless there is a room in which the lights are never turned on. If you don't have such a room, place your poinsettia in a dark closet or cover it with a cardboard box each night for the required 12 hours. If using a cardboard box, tape all the seams with duct tape to cut off any light. Poinsettia takes anywhere between eight and 11 weeks to flower once the dark treatment has been started. Normally, people start the dark treatment in early October. The first six weeks are critical. For every night you miss during the first six weeks, add two days to the bloom time. After the six-week dark treatment, the buds have set and the dark treatment is no longer needed. (WU)
We have been seeing some twig dieback on pin and other red oaks recently that has been caused by a fungal disease called Botryosphaeria canker. Affected trees show a wilting or "flagging" of the terminal growth on the ends of branches. Dieback usually extends 4 to 6 inches down the twig with leaves bending back toward the twig before turning brown. Dead leaves remain attached to the tree. If you look closely at the twig you should see a rather marked transition from healthy to diseased tissue. Take a knife and scrape away some of the outer bark tissue. Healthy tissue is a light green whereas diseased tissue tends toward brown to black.
This differs from oak wilt in that whole branches are affected from oak wilt. Botryosphaeria canker affects only the tips of branches.
The last time I remember an outbreak of this disease was 1997. It appears stressed plants are more likely to be damaged. The hot dry spell this summer probably contributed to the problem. This disease causes such minor damage that chemical control measures are unwarranted. Dead twigs on small trees may be pruned off if desired. (WU)
There has been a recent spate of telephone calls regarding caterpillars feeding on various shade trees and woody ornamentals. And just as varied as the host plants are the different larval species currently active in Kansas.
Two species are associated with webbing: mimosa webworms and fall webworms. Both species vary from year to year in their abundance between geographical locations as well as within certain areas. For instance, mimosa webworm activity in Manhattan varies depending where one is within the city. Some trees appear completely brown, whereas others show no signs of any mimosa webworm activities. Fall webworm activities are mostly absent in the Manhattan area but more prominent east of Topeka and in southeast Kansas. But even in these areas, the current degree of webbing activities in no way matches the amount seen several years ago in the late nineties.
Mimosa webworms are named for the host plant upon which they mainly infested after their introduction from China back in the 1940's. However, they have moved over to honey locusts as the tree that they do well on (of course, they do well on mimosa, but mimosa trees - in Kansas - are not as commonplace as honey locusts. Although some honey locust cultivars are considered to be less-susceptible to mimosa webworm, they too succumb to the feeding activities of mimosa webworms under heavy population pressures. Treatments at this time are not recommended. The damage is done. And despite the current unattractiveness of "browned trees/leaves", come springtime, trees will leaf-out and regain their green beauty.
Fall webworms are well into their cycles, and again, there is little to be gained trying to eliminate them. While (for our purposes) it is academic as to which race of fall webworms is present, probably the red-headed race is most common at this time of year, especially feeding on walnut and pecan trees, and on sumac along roadsides "out in the country". If webbing is objectionable, simply pull out/break up the webbing. But do not prune out branches with web masses--those branches are alive and healthy, and will produce a new flush of leaves next spring.
There are four species of caterpillars that people are reporting: walnut caterpillars, yellownecked caterpillars, sumac/blacknecked caterpillars, and greenstriped mapleworm. The first three are closely related larvae of notodontid moths. And basically, all can be addressed at the same time. Walnut caterpillars are associated with walnut and pecan. As mature larvae, they are very dark/grey and densely covered with long white hairs. Sumac/blacknecked caterpillars are restricted to the various sumac species. Only yellow-necked caterpillars have a more varied host range (crabapple, peach, cherry, maple, elm, oak, walnut, pecan, locust, sumac and more). Yellownecked caterpillars are so named for the light colored prothoracic shield/ "neck" immediately behind the black head capsule. This varies from yellowish to orangish to light brown in color. The "neck" of the blacknecked/sumac caterpillar is decidedly black.
Greenstriped mapleworms are the larvae of a saturnid moth (related to the large showy luna, cercropia and polyphemus moths). They are almost exclusively restricted to maples (primarily silver maples due to the prevalence of this maple species in Kansas), but also reportedly (on occasion) on oak. Currently, the second generation larvae are those in question.
With any of these latter four species, it is recommended that they be left to run their course-complete their feeding. They are at the end of their feeding period by the time they are noted. Any additional foliar feeding will be minimal. And also important to consider is the fact that trees are fast approaching that time of year when they will be shutting down for the season. There is little lost by these late-season defoliations. And for every leaf consumed, well, that is one less leaf to rake in the fall of the year. Plus, trees will leaf out in normal fashion next spring. (BB)
Contributors:
Ward Upham, Extension Associate; Bob Bauernfeind, Entomologist; Matt Fagerness, Turfgrass
Horticulture 2006 E-mail Subscription
For questions or further information contact: Hort
WebMeister.
KSU, County Extension Councils, Extension Districts, and U.S. Department of Agriculture
Cooperating.
All educational programs and materials available without discrimination on the basis of
race, color, national origin, sex, age, or disability.
Extension Horticulture Home Page | Horticulture Information Center