Extension Fall Garden Packet--III
Published: Sep. 5, 2007
NOTE TO EDITORS: This is the final installment of University of Illinois Extension's Fall Garden Packet.
September 5, 2007
Source: Martha Smith (309) 836-2363 Contact: Bob Sampson (217) 244-0225 Extension Communications Specialist e-mail: rsampson@uiuc.edu
Browning Evergreen Foliage
Every fall, some people become upset when the foliage on their evergreens changes color dramatically, said a University of Illinois Extension horticulture educator.
"People are convinced that their plants must have some type of virus or fungus and want to know what can be done," said Martha Smith. "There is really nothing to be concerned about. What is happening is commonly called inner needle drop or third-year needle drop."
All trees and shrubs renew their foliage annually, producing new leaves in the spring of the year and shedding old leaves in the fall, she explained. The leaves of deciduous plants such as maples and oaks live for one growing season and then fall off, usually in a blaze of color.
"But evergreen foliage lives from one to several years, depending on the species," she said. "As new growth emerges in the spring, last year's growth becomes shaded. Its role as primary photosynthesizer is over. During late September and October, this inner or older foliage dies and falls away."
In some species like white pine and arborvitae, this fall browning takes place rather suddenly. The older needles turn a bright gold-yellow and remain attached for about seven to 10 days, depending on weather.
"If we have strong autumn winds and heavy rains, those needles fall quickly," Smith said. "Sometimes, this natural occurrence is hardly noticed. But every few years it is very noticeable, and people become concerned."
This natural foliage drop may be distinguished from cases of severe foliage damage due to disease by its uniform appearance over the whole tree and its common occurrence on neighboring trees of the same kind. It is also confined to the innermost or oldest needles. Nearly all pines bear needles in bundles of two or five, and the needles remain together when they drop.
"No harm is done to the tree by the loss of this foliage," she said. "The amount dropped depends somewhat on the condition of the tree and the preceding growing seasons. Less vigorous individuals will lose a greater proportion of their total leaf area. If the new, terminal, or current year's growth is fresh and vigorous, the health of the tree is not in jeopardy."
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September 5, 2007
Source: Martha Smith (309) 836-2363 Contact: Bob Sampson (217) 244-0225 Extension Communications Specialist e-mail: rsampson@uiuc.edu
Deep Watering Evergreens
Be proactive and deep water your evergreens this fall, said a University of Illinois Extension horticulture educator.
?Water as much of the root zone as possible,? said Martha Smith. ?Don?t water at the base of the trunk but water out near the drip line?the outside perimeter of foliage. More water-absorbing roots are in this area.
?Place a hose on a slow trickle and let the water soak in. Move the hose around the plant to ensure you are reaching as much of the root zone as possible.?
This is necessary because a major concern for evergreens is winter survival if the plants have little soil moisture. Pine, spruce, fir, yew, juniper, and arborvitae are easily stressed from summer?s extreme temperatures and are in real danger if they can?t pull moisture from the soil to replace what is normally lost due to winter weather, she noted.
?As a result, evergreens can dry up, turn brown, and die in the spring,? she said.
During the winter dormant season, top growth ceases in evergreens. However, roots are still active until soil temperatures drop below 35 degrees F.
?Evergreen foliage is exposed to the elements all year round,? Smith said. ?Winter winds pull out available moisture, and the roots need to take up moisture to replace this loss.?
A dry growing season followed by a cold windy winter with little snow can trigger damage in evergreens. The wind blows over the evergreen foliage and sucks out any available moisture.
?In February and March, we often have warm, spring-like days,? she said. ?It is at these times that the evergreens try to replace what moisture they have lost. If the soil is dry, the plants suffer.
?In comparison, deciduous material such as maples and oaks lose very little moisture in the winter. When their leaves emerge, it usually means we are experiencing ample spring rain to allow for adequate water uptake.?
Smith also recommended that homeowners avoid using any de-icer materials along walkways or roads near evergreens. Salt-laden runoff can restrict water uptake.
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September 5, 2007
Source: Richard Hentschel (630) 685-2317 Contact: Bob Sampson Extension Communications Specialist Phone (217) 244-0225; rsampson@uiuc.edu
Fall Lawn Care
Managing your lawn in the fall will ensure a fuller, greener lawn next spring, said a University of Illinois Extension horticulture specialist.
?Taking care of your lawn this fall really depends on the kind of summer temperatures and the amount of rainfall you have had,? said Richard Hentschel.
?In parts of Illinois where rainfall has been plentiful, homeowners have had to mow more often than expected to keep up with the rapid growth and maintain the one-third rule of removing no more than one-third of the grass at a mowing.?
If you have had that amount of rain along with high temperatures, turf grass diseases have been a problem and may have left your lawn thinner than you?d like, he added. If rainfall has not been plentiful, your lawn may be thinned due to drought.
?You may need to over-seed thinned areas or re-seed bare areas of your lawn, and fall is a great time to do that,? he said. ?Since most weed seeds tend to germinate in the spring of the year, you get a much better stand of new grass in the fall. Whatever method you use, be sure to purchase high-quality disease-resistant seed.?
Prior to seeding, lightly top-dressing the area is recommended. Top-dressing serves two purposes. First, it provides a seedbed for the new turf seed and, second, it fills in those low spots that held extra soil moisture which likely contributed to lawn diseases.
?Timing is also important to allow for adequate establishment of your new seeding before cold weather moves in for the winter,? Hentschel said. ?In northern Illinois, for example, fall seeding is best done mid-August through mid-September. Any later than that and you gamble that the new seedlings will be hardened off in time before cold weather arrives.
?For central Illinois, you can go a little farther into September and in southern Illinois usually to the end of September.?
Fall is also a great time to put down fertilizer, as most of our grasses are still putting food into reserves and expanding root systems before cold weather. If you only fertilize once a year, fall is the best time?just stay away from high-nitrogen fertilizers in the fall.
?Another cultural management practice that is beneficial to the lawn in the fall is core aeration,? he said. ?This opens up compacted soil from traffic patterns made by kids, pets, or?next to the driveway?by car tires hitting the lawn. Knotweed is a good indicator plant for compaction.
?Core aeration is also great for managing the thatch layer that develops in your lawn. Thatch will catch the water and prevent it from getting down into the soil. As a result, grass roots tend to stay near the surface rather than growing deeper into the soil. Leave the cores on the surface and let them dry out. The next time you mow, they will break up and disappear. You can rent these machines and split the cost with a neighbor.?
A fall broadleaf weed control will eliminate the need for a spring treatment to get rid of dandelions. Because lawn weeds are also putting food reserves into their root systems, fall treatments often give better and more consistent results than a spring application.
?Continue to mow the lawn as long as the grass grows,? he said. ?This might mean wearing your coat and gloves for that final mowing in late October or even into November.
?One of the easiest ways to make sure your lawn looks good is to have a sharp mower blade. This is very important if you are using a mulching-style mower. A dull blade will not cut cleanly, leaving a ragged, uneven cut.?
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September 5, 2007
Source: David Robson (217) Contact: Bob Sampson (217) 244-0225 Extension Communications Specialist e-mail: rsampson@uiuc.edu
Overwintering Geraniums
You can beat the frost and save your geraniums by taking them inside to overwinter, said a University of Illinois Extension horticulture educator.
?As soon as we get freezing temperatures, most unprotected annual geraniums will turn a mushy green and die,? said David Robson. ?However, it?s possible to take those geraniums before they get nipped by a hard frost and overwinter them indoors.
?You can pot up the plants, take cuttings, or store the plants as bare-root specimens. No matter what method you choose, understand that success isn?t guaranteed. The headaches and heartaches may not be worth it, especially since geraniums can easily be purchased every spring.?
It is important to make sure the plants you attempt to overwinter are vigorous, healthy, and insect and disease free.
?If you grew your geraniums in individual pots for the summer, you probably don?t have much to do except examine each plant carefully to make sure you?re not bringing insects indoors,? he said. ?White flies, aphids, and mealy bugs can hide on a plant. Outdoors, they don?t cause many problems as there are predators to keep them in check. Indoors, though, those predators aren?t around.
?Make sure to check the soil to avoid bringing in other hitchhikers. Some gardeners will always re-pot the geranium in fresh houseplant soil. That might be a little unnecessary, though it practically guarantees no soil-borne insects are brought indoors,? he said.
For plants in larger pots or in the ground, carefully dig the geranium and plant in a six- or eight-inch pot. Use potting soil instead of garden soil to avoid a soggy, heavy soil indoors. Prune back each plant by half.
?Geraniums need at least 10 to 12 hours of light indoors ideally,? he noted. ?Place the plants in a bright south window or under fluorescent lights.
?Indoor temperatures are just as important. Geraniums, by nature, are more of an arid plant; they prefer warm?65 to 70 degrees F?day temperatures and cool night temperatures of 55 to 60 degrees F. Excessively warm temperatures may result in leggy plants.?
Using the cutting approach allows using smaller plants that take up less space and have a better chance of acclimating to indoor light, temperature, and humidity levels.
?Take four to six inches of terminal growth and strip off the bottom two to three inches of leaves,? Robson said. ?Dip each cutting in a rooting hormone. Stick the cuttings in sand, perlite, or vermiculite up to the first set of leaves. Water thoroughly and place in a bright sunny window or under fluorescent lights. Cuttings should root in one or two months.
?When rooted, pot in a three- or four-inch pot and continue to grow until spring.?
The bare root approach is by far the easiest but also the least successful, Robson said. It involves digging the geraniums up, shaking most of the soil from the roots, and hanging them upside down in a cool basement or dry crawl space where temperatures hover around 45 to 50 degrees F.
?Once a month, soak the roots for an hour or two in warm water,? he said. ?Expect that leaves will probably turn brown, dry up, and fall off. If all goes well, though, stems should remain green.
?In March, cut each plant back by half or to green, fleshy, solid stems. Pot each plant up and water thoroughly, placing the geraniums in a bright, sunny window. Plants should start budding out, sending out new shoots, and developing into attractive plants that can be set outside in May.?
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