Fall Extension Garden Packet 08-2
August 28, 2008
  • /Crop Sciences
NOTE TO EDITORS: This is the second of three installments for University of Illinois Extension's Fall Garden Packet. The final installment will be sent Aug. 29. Thank you for your consideration. Bob Sampson, Extension Communications Specialist

August 28, 2008

Source: Richard Hentschel (630) 685-2317 Contact: Bob Sampson Extension Communications Specialist Phone (217) 244-0225; rsampson@uiuc.edu

Plant that Tree

Fall is a great time for planting trees in your landscape, said a University of Illinois Extension horticulture specialist.

"Large retail nurseries will often let you tag a tree to be dug later," said Richard Hentschel. "Trees are also available at retail garden and nursery centers. A tree that has a trunk diameter of two to two-and-a-half inches is a pretty good-sized tree for the homeowner.

"At that size, the tree is not so small that the canopy has not developed but not too big to handle once you get it home."

Nursery-grown trees will be root-pruned, creating a root system closer to the trunk. Canopies will have been properly trained and pruned to provide homeowners with a good start to getting shade in their yards.

"Research indicates that how a tree is planted can make a big difference in how quickly and how well it establishes itself in your yard," he said. "Trees planted too deep are the main cause of poor establishments in most situations involving urban landscapes with heavily disturbed or heavy clay soils.

"Roots will naturally grow down into the soil profile but find it very hard to grow upwards in the soil. Disturbed soils lack the proper pore spaces that allow air and water free movement in the soil."

An important factor in determining if the tree establishes itself or languishes is the planting hole you dig, he added.

"Trees that are slow to establish are often easy targets for insects and diseases," he said. "The hole should be no deeper than the measured ball and two to three times as wide near the top of the measured ball. If there is a question of the soil draining properly, you can dig a slightly shallower hole and the roots will naturally grow down to their desired level.

"Since many of the feeding roots live in the upper 12 inches or so of soil, they really benefit from the planting hole being a lot wider at the top third."

Once the tree is in the hole and sitting straight, backfill the hole with the dirt you dug out. When the hole is about three-fourths filled, settle that soil by adding water. After the water has settled the soil, continue filling the hole and creating a watering berm with any leftover soil.

"Apply more water to settle the newly added soil," he said. "Make sure to check the moisture in the ball and surrounding soil regularly. Water when needed."

For trees planted in the late fall, the time the roots have to grow out into the soil can be extended by mulching. This keeps the soil from getting too cold, allowing the roots several more weeks to grow. Be sure to water one last time before the ground freezes.

"Thin-barked trees will need to have the trunk wrapped to prevent sun scalding and freeze cracks," Hentschel said. "Once good spring weather returns, you can remove the wrap. By the second winter, the tree will have adapted to its current orientation and you will not need to wrap it again."

How long does it take a tree to recover from the initial planting?

"You can count on at least one year for every inch of trunk diameter," he said. "During this time, gardeners will need to continue monitoring the tree and providing water. Visual signs that the tree has recovered from transplanting will be leaves of normal size, an increasing annual growth rate, and a fuller canopy of foliage.

"If you have a larger tree, the recovery time will be even longer. Just remember, the longer the recovery time, the more time insects and diseases have to find your tree."

-30- August 28, 2008

Source: Nancy Pollard (708) 720-7500 Contact: Bob Sampson (217) 244-0225 Extension Communications Specialist e-mail: rsampson@uiuc.edu

Picking Trees for the Long Term

Many trees can be planted in the early fall, allowing the advantage of warm soil for root growth before the tree goes dormant, said a University of Illinois Extension horticulture educator.

"With trees in their full fall beauty, this is a good time to get an idea of what kind of tree you might like for your yard," said Nancy Pollard. "How do you choose a tree you can live with for years to come?

"One way is to follow three tips for successfully choosing a tree."

Begin by looking at the site where you intend to plant the tree.

"Choosing an appropriate site will minimize costly, harmful, or drastic later tree pruning or the premature death of the tree," she said. "Every kind of tree has a unique height, width, and spacing, as well as environmental needs to fully mature. Pick a tree that fits in the space and is well adapted to your site."

Take a good look at the site.

"Look up. Do you see wires?" she said. "Avoid planting under electrical wires, or, if you do, chose a short variety.

"Look down. Find out where underground utilities are by calling 811 before you dig. Plant at least 10 feet away from utilities. Look around. Will views of traffic signs, pedestrians, or vehicles be obstructed as the tree grows? What other physical features are nearby?"

Finally, she added, observe the growth environment. Is it sunny or shady? Does the soil drain well? What is the soil pH? Is the soil compacted by foot or vehicle traffic? How much root space is there?

The second tip is--pick a tree to match your site.

"When fully grown, how big will the tree be compared to the space available?" she said. "The mature crown should be 10 feet or more from utility lines. Will it need to be pruned away from buildings? Will it obstruct signs or views?

"Is the tree native or well-adapted for your site? Is it prone to common diseases or insect pests typical of the region? Answering these questions may take research. Be sure to choose disease and insect-resistant tree varieties."

Determine what kind of maintenance will be required in the short- or long-term. Will falling leaves and fruit need to be removed, or can they be left for wildlife? What seasons will showcase the tree at its most interesting?

"There are some resources to help you match the right tree to the right location," she noted. "A good place to start is a University of Illinois Extension website (http://www.extension.uiuc.edu/cook/urbanhort.html)."

The third tip involves picking a good tree at the nursery or garden center.

"Is the trunk straight?" she said. "Choose a tree with a straight, single central leader. If it has multiple leaders, look for wide branch angles. As they get older, narrow-angled branch V's are prone to split during storms. Good selection and early pruning out of narrow V's reduces storm splitting.

"Is the trunk wounded? Reject trees with wounded trunks. Is the crown full and well balanced? Are there many crossing branches that rub and create wounds that will need to be pruned out? Will narrow V's have to be removed to keep the tree strong? How will corrective pruning affect the crown balance?"

Also check to determine if you need to purchase mulch or woodchips at the same time the tree is purchased. Mulches keep soil cool and reduce water loss, thereby lowering stress during drought and keeping weeds at bay.

"They also protect the trunk from wounds that lead to shortened tree life," she said.

-30- August 28, 2008

Source: Maurice Ogutu (708) 352-0109 Contact: Bob Sampson Extension Communications Specialist Phone (217) 244-0225; rsampson@uiuc.edu

Picking and Storing Apples and Pears

As fall approaches, many homeowners with fruit trees would like to know when to pick their apples and pears, said a University of Illinois Extension horticulture educator.

"Apples and pears tend to have different maturity indicators that will help the backyard orchardist know when fruits are mature," explained Maurice Ogutu. "Fruits tend to mature based on weather conditions and where they are grown in the state. Fruit maturity is late in northern parts of the state compared to the central and southern parts."

For apples, the time to pick is when the fruit is fully mature but before it becomes overripe.

"When to pick apples can also be determined by the time elapsed between full blooms and when it is picked, changes in ground color or flesh, and ease of separation of the fruit from the spur," he said. "The maturity indicators for apples are color, ease of separation, fruit drop, and softness and flavor.

"Color both outside and beneath the skin is a very important indicator of maturity. In varieties of apples that are yellow, when green gives way to yellow, then it is mature. The change of flesh color from green to white is also a sign of maturity in apples."

Ease of separation from the spur usually occurs in mature apples, he noted. When testing if the apple fruit is mature, do not pull it down but twist it upwards with a rotating motion. Dropping of good fruit from the tree is a signal that the fruits on the tree are mature.

"When apple fruits become softer and taste sweet and juicy, this indicates maturity, although there are some varieties that become sweeter in storage such as the Delicious," he said.

Pears, however, are picked before they are ripe and continue to ripen in storage. Mature pear fruit detaches from the fruit stem when held at a horizontal position from the usual vertical hanging position.

"However, some varieties such as Bosc are very hard to separate from the spur," he said. "Pears picked when the fruit is mature and starting to ripen will ripen better in storage.

"It is also very important to know the usual period of maturity for each variety."

Color and size of the fruit are very important factors to determine pear fruit maturity. The yellow pear varieties, such as Bartlett, D'Anjou, and Comice, show a change in skin color to a lighter shade of green at maturity.

"The flesh becomes whiter, and juice will ooze on a cut surface," he noted. "When pear fruits are mature, they should be at least two inches in diameter at the widest portion of the fruit except fruits from the Seckel variety.

"The larger fruits are mature so it is advisable to start picking larger fruits first and then smaller ones when they have reached the right size."

Fruits that are not going to be used immediately should be stored. Separate bruised and damaged fruits and store those that are in good condition. Store apples and pears in well-ventilated containers immediately after they are picked. The storage temperature should be 30 to 32 degrees F in a humid environment.

"Do not store fruits with onions, potatoes, or other strong-smelling vegetables and herbs, as the fruits will absorb the flavors," Ogutu said. "Inspect the fruits regularly and remove the ones with excessive ripening, mold, freezing, or flesh breakdown.

"Check storage temperatures to ensure that fruits are not frozen, particularly apples. Partly frozen pears can be thawed and still maintain their quality, but freezing usually ruins apples."

Ripen pears before they are ready for consumption, he added. The storage lives of apples and pears vary according to variety, storage temperature, and relative humidity.


August 28, 2008

Source: Jennifer Schultz Nelson (217) 877-6042 Contact: Bob Sampson (217) 244-0225 Extension Communications Specialist e-mail: rsampson@uiuc.edu


Grow cranberries in Illinois? It may not be that farfetched, said a University of Illinois Extension horticulture educator.

"In theory, at least, you should be able to grow cranberries in Illinois if given the right conditions," said Jennifer Schultz Nelson. "I've seen cranberries marketed in catalogs and at local garden centers as groundcover in recent years. Their evergreen color and creeping growth habit would make a very attractive ground cover in many situations. However, most homeowners would have to do some pretty serious soil amending to get the acidic, sandy conditions that cranberries love.

"But if that doesn't deter you, there's a good chance that with a little attention and proper fertilizing you could grow some cranberries of your own."

Most people don't pay much attention to cranberries except during the holiday season. As Thanksgiving approaches, fresh cranberries will again start to be available in the grocery store. How in the world do they get there? Do they grow on a tree, a plant, or what?

"The answers may surprise you," she said. "As natives to North America, cranberries are truly an American fruit. Back in the 1660s, English colonists found cranberries growing wild in what are now southern Canada and the northeastern United States. Native Americans used them along with other berries as a food source.

"However, there is no solid evidence that cranberries were present at the first Thanksgiving. They certainly could have been, but the written accounts that exist do not specifically mention them."

Nelson remembers as a child being taught in school that cranberries grew in bogs.

"So for a very long time, I had this picture in my mind of cranberries bobbing along in some sort of swampy bog, growing on huge bushes," she said. "In reality, nothing could be further from the truth."

Cranberries are actually a creeping evergreen shrub--hence, the use as a groundcover plant--whose stem may stand as high as eight inches above the ground on a good day. The upright stems arise from an underground rhizome, which is technically modified stem tissue itself.

The leaves are exceedingly tiny, at only one-fourth to one-half inch in length. The leaves live for two seasons before being shed.

Flowers bloom on cranberry plants in late June and early July. Whitish-pink flowers occur singly at the end of the upright stems. The flowers hang downward, giving them an upside-down appearance. The flower's resemblance to the head of a crane is the source of its original name--crane berry, which shortened over time to cranberry.

These flowers self-pollinate, and the berries that develop start out green, then turn white, and are deep red when fully ripe. This process can take anywhere from 60 to 120 days after pollination, depending on the weather and the cultivar.

"You may have noticed a somewhat new product in the juice aisle of your local supermarket called white cranberry juice," Nelson said. "Sounds pretty exclusive and special, doesn't it? In reality, the juice comes from white cranberries, but they are not some special cultivar. Rather, they are fully mature but unripe cranberries.

"Before someone had the idea to market them as a 'special' juice, they would have reduced the quality of a batch of cranberries brought in for processing. Now, there's a market for them."

Cranberries prefer acidic, sandy soil with added organic matter. Often peat moss is used as the source of organic matter. The idea of a "cranberry bog" comes from the methods used to harvest the fruit and provide winter protection for the plants.

"For every acre of cranberries grown, there are anywhere from three to 10 acres of 'support' land used to store or transport water for the cranberries," Nelson said. "These plants are very flood-tolerant but very sensitive to drying out in cold winter winds.

"The fields are flooded for the winter to protect the plants. This is especially important since next year's flower buds develop at the end of the current growing season. If portions of the plants die over the winter, this will potentially decrease the next year's crop yield."

But what about those television commercials featuring the fellows standing hip-deep in a cranberry bog?

"Fall is the prime time for harvesting cranberries, and they can be harvested dry, using a series of rakes to 'comb' the berries off the plants," she said. "The more common method is a 'wet' harvest, where individual fields are flooded, and the ripe berries float to the top and are herded to one side and loaded onto a conveyor and into a truck."

At the processing plant, the berries are sorted first by bouncing and later by hand.

"It sounds silly, but a good-quality cranberry will bounce whereas a bad one will just make a dull thud," she said. Only a very small percentage of cranberries make it to market as a fresh berry during the holiday season. Another small percentage is sweetened, dried, and marketed as a raisin-like dried fruit.

"About 90 to 95 percent of cranberries end up in a juice or sauce product."

Cranberries are somewhat unique in the world of fruit because they can be refrigerated without losing quality for several months, and even longer if frozen. This makes it possible to spread out the processing of the berries into juice, sauce, and dried products over the year.

Wisconsin produces about half of the national cranberry crop. Massachusetts is runner-up with about one-third of the crop, with the rest grown in Oregon, Washington, and New Jersey.

And for would-be Illinois growers, Nelson has a bit of good news.

"You don't necessarily have to overwinter your plants underwater--a good layer of mulch or floating row cover will also combat the drying winter winds," she said.


August 28, 2008

Source: Martha Smith (309) 836-2363 Contact: Bob Sampson (217) 244-0225 Extension Communications Specialist e-mail: rsampson@uiuc.edu

Mushrooms in the Lawn

While rain is often desperately desired for home lawns and gardens, it can bring problems, said a University of Illinois Extension horticulture educator.

"High humidity and excess moisture lead to plant problems," said Martha Smith. "One of those 'problems' can pop up quickly literally overnight--mushrooms."

Mushrooms, sometimes called toadstools, are the reproductive or fruiting stage of fungi. They are quite common following prolonged wet weather and often disappear as soon as soils start to dry.

"The majority of mushrooms are nuisance problems, appearing repeatedly if conditions are right. They may have an odor," she said. "They are annoying but cause no damage to the grass or to our landscape plants. Most fungi in lawns are beneficial because they decompose organic matter buried in the soil, releasing nutrients that are then available for plant growth."

The mushroom is the reproductive stage. At that stage it can produce and release tiny spores that are carried by the wind to new sites. The mushrooms growing in your lawn could have blown in from your neighbor down the street or across town.

"When spores reach a favorable place to grow, they germinate and send out long, thin filaments called hyphae," she said. "Hyphae decompose wood such as an old stump or the roots left behind from a tree cut down several years ago or construction debris buried after the house was built or the sunroom added on.

"A single hyphae is too small to be seen by the naked eye, but groups of hyphae can be visible as a mass of thread-like growth known as mycelium. When mycelium has developed sufficiently, mushrooms pop up. These nuisance fungi can survive in soil for years and will only produce fruiting structures when conditions are favorable."

There is nothing homeowners can do to keep mushrooms from coming up. Merely removing the mushroom doesn't remove the underground portion from which they are growing.

"But removing them will prevent them from spreading more spores that can lead to future pop-ups," Smith said. "Simply mow them off or take them up and discard them. Remember, they may continue to appear periodically over the next several years during favorable environmental conditions until the organic matter they are feeding on is gone.

"Never eat mushrooms growing in your lawn or garden. The majority are poisonous. Removing them eliminates any potential attraction for curious children and pets."