Yard & Garden Line News September 1, 2002

Yard & Garden Line News
Volume 4 Number 14 September 1, 2002

Features this issue:
Is Your Black Walnut Worth Big Bucks?
A September Gardening Calendar
Tough Turf Times
Birch Catkin Feeders
Horsehair Worms
What To Do About Squash Bugs
Open House at the Southern Research and Outreach Center--
"Connecting Agriculture and the Community"
Editorial Notes

Is Your Black Walnut Worth Big Bucks?
Meagan Keefe, Assistant Extension Specialist, Forest Resources

Black walnuts. Photo credit: Jim Calkins

Homeowners often call the Forest Resources Extension office with questions regarding their black walnut trees. Sometimes it is to ask why nothing seems to grow under them, but more often it is to ask whether or not there is anyone out there who buys them. They have heard somewhere that these trees are worth quite a bit of money. Unfortunately, this is not usually true for walnuts grown in an urban setting. Black walnut (Juglans nigra) has often been used for furniture, art, gun stocks, and other wood products because of the color, grain and ease of working with the wood. While most logs are turned into lumber, the best logs are turned into veneer. Veneer is a very thin sheet of wood that can be used to cover another species of wood or plywood to give it the appearance of another, in this case, walnut. This allows walnut looking products to be produced at a much lower cost.

Whether the walnut will be used for lumber or veneer, there are several characteristics that determine whether or not the tree is valuable for sale, including trunk diameter, height, branching and whether or not the tree is free of defects. Another concern with urban walnuts is what could possibly be in the trunk itself. An old eye screw from a hammock may be in the tree unknown to both the current owners and therefore could cause harm to the person removing the tree.

Trunk diameter is measured at 4-1/2 feet off the ground. It can be found by measuring around the circumference of the tree and dividing the circumference by 3.14. Most buyers look for trees with a diameter of more than 18 inches. A few may purchase smaller diameter trees if they are a part of a group, but those with a diameter of less than 15 inches are of relatively little value.

Tree height is also taken into consideration. Merchantable height means the trunk height from the base to the point where major branches or trunk forking begin. A buyer will look for trees that would contain logs with a merchantable height of 8-10 feet (this is especially the case for logs that may be used for veneer). In most cases more than one log is necessary for consideration by a buyer.

Tree quality is another consideration. This is measured by how free the trunk is from defects such as crookedness, branches, holes, bumps, cracks, scars, insect or disease damage and wounds. The fewer the defects, the more valuable the tree. In general, the trees with a large diameter and a long trunk free from most defects are the ones that have the greatest potential for being a valuable lumber or veneer tree.

Most trees grown in an urban setting, however, do not usually exhibit these characteristics. An urban tree doesn't have to compete with surrounding trees for light and therefore will often have a shorter trunk with many branches low to the ground. This gives the tree little if any merchantable height. Urban trees are also more likely to have been injured or subject to disease than a tree grown in the forest.

The biggest reason why most buyers will not purchase urban walnuts is the potential risk that they may contain objects imbedded in the trunk that could pose a substantial risk for injury when removing and processing the tree. If the tree is large enough for the owner to consider selling it for lumber, it could very likely have foreign object from 25-50 years ago in its trunk that the owner would have no way of knowing existed.

The last factor is the difficulty and cost of coming to harvest one or two trees in an urban setting. It often makes little economic sense for a buyer to bring a crew and equipment in to harvest the tree. Also, most urban trees grow fairly close to houses, power lines and other structures that make it difficult, expensive and time consuming to harvest.

Although walnuts are not often considered the ideal shade tree for the yard because of the chemical juglone they secrete discourages other plants growing around them; this is often their highest value to the homeowner. A large tree can provide shade, beauty and real-estate value to a home that may not be recovered by trying to sell it for lumber.

If you think you may have a tree that does meet the characteristics for a valuable lumber or veneer tree, feel free to contact the Forest Resources Extension Office at 612-624-3020 or treeinfo@umn.edu for further information. Otherwise, sit back and enjoy the beauty of your tree.

A September Gardening Calendar
Deborah Brown, Extension Horticulturist

'Autumn Red'--a new My Favorite mum. Photo credit: My Favorite Co.

After a long, cool June followed by a horribly hot July (and tons of water in many parts of the state), it's hard to believe the gardening season is already winding down. But one look at the calendar tells us otherwise. Here are some future-oriented garden and landscape activities that will help put a positive spin on September's arrival:

Plant Flowering Perennials

Despite our unpredictable climate, we are blessed with literally hundreds of beautiful flowering perennials that thrive here. If you want to expand your flower beds (what better way to reduce the amount lawn you'll need to care for?) or simply add more perennials to replace some of your annuals, early autumn is an excellent time to plant. And as a bonus, many garden centers sell potted specimens at reduced prices this time of year.

When planting perennials in September, the sooner you can get them into the ground, the better. You want at least three or four weeks of decent growing conditions before more harsh weather sets in. Add about two inches of mulch around the plants right away. Then when the soil begins to freeze sometime in late October or November, cut the foliage close to the ground and cover the plants with six or more inches of straw, leaves, or other mulching materials.

Plant Bulbs for Spring and Summer Displays

Spring flowering
bulbs. Photo credit: Netherlands Flower Bulb Info

Potted mum. Photo credit: Plant Exch.

Pansies. Photo credit: Deb Brown

Most people realize that spring-flowering bulbs are planted in fall. But bulbs don't always get planted in time to develop enough roots to help them through winter in good condition. Tulips are pretty tough, but daffodils, hyacinths, crocus, Siberian squill, and other small bulbs will probably perform best if you can plant them later this month, rather than waiting until late October or November to get them into the ground. A combination of rainfall and periodic watering until the soil freezes will encourage them to form plenty of roots.

Whether you buy locally or order from a catalog, your choice of bulbs will be better now than later. And, it shouldn't be difficult to find a pleasant day for planting. Getting down on your hands and knees to plant bulbs in cold damp soil on a chilly, raw day is no one's idea of a good time. Regardless of when you plant them, mulch bulbs as you would flowering perennials, once the soil surface freezes. Any bulbs that don't make it into the garden this fall will have to be forced for indoor bloom. You can't hang on to them and expect good results planting them next spring.

In addition to planting spring-flowering bulbs, mid-September though October is the ideal time to plant both Asiatic and oriental garden lily bulbs for blooms next summer. There are so many beautiful bulb cultivars that it's tempting to buy one of each. Resist that urge and plant groups of the same variety, using either three – or better yet, five – identical bulbs in each cluster. If your site provides full sun and well-drained soil, summer bulb clusters will expand over the years, especially the Asiatics which are hardier than the orientals.

Add Evergreens to Your Landscape

By September you've had plenty of opportunity to assess junipers, arbovitae, and other evergreens that may have suffered winter injury last year. If they haven't filled in over the summer, take advantage of fall sales to replace them. Or, if you're looking to add color and improve the appearance of your winter landscape, consider adding pine, spruce, or fir trees for the future. In either case, don't feel compelled to plant the largest specimens you can find and afford. Smaller evergreens will transplant more easily and generally "take off" faster after transplanting.

Early autumn is really an excellent time to plant young evergreens. They'll have the chance to begin becoming established in their new location, since roots will remain active until the ground freezes later in the season. By mulching them with several inches of shredded bark you can keep that soil from freezing as early as it would otherwise, allowing you to continue watering them longer.

Deciduous trees and shrubs may be planted in September, but they can also be planted after they've gone dormant and have lost their leaves. Evergreens hang on to most of their leaves (needles), and continue to lose moisture through those needles all winter long, which is why it's more critical that you plant them earlier in the season so their roots begin to function.

Help Your Lawn

Right now, through the middle of this month, you can overseed thin areas in your lawn with the expectation that new grass plants will develop strong enough roots to carry them through winter and come back thicker next spring. It's also important to fertilize right away. Then apply fertilizer a second time towards the end of October. Because roots will still be active, nutrients in your lawn fertilizer will help develop those underground portions rather than encouraging more growth above ground. The result will be an earlier green up next spring, and a thicker, stronger stand of grass.

Highlight Your Entryway With Pots of Instant Color Last but not least, put yourself in an autumn frame of mind by picking up several large pots of fall colored chrysanthemums to perk up your entryway. You'll find them everywhere from garden centers to grocery chains and builder's supply mega-stores, offered for sale at very affordable prices. Choose plants with buds just beginning to open, so you'll be able to enjoy them for weeks.

Look, too, for containers of pansies, violas, and johnny jump-ups. These colorful annuals are usually associated with spring, when weather is cool, but lately garden centers have realized that they make excellent flowers for fall – for the same reason. They can even tolerate light frosts, just like chrysanthemums.

Tough Turf Times
Janna Beckerman, Extension Plant Pathologist

Overall view.
Photo credit: Y & G client

Discolored blades. Photo credit:
Janna Beckerman

Spores on blades Photo credit:
Janna Beckerman

My Grandmother had a saying that bad things always happened in threes. That saying certainly applies to the problems that our turfgrass has been faced with this year! We started the season with Septoria leaf blight, followed by Ascochyta leaf blight. As the weather warmed, but the rains continued, Leptosphaerulina leaf blight, emerged as the epidemic of August.

The fungus Leptosphaerulina australis, is considered a minor pathogen. Try telling that to distraught homeowners! This disease flares up in warm to hot, wet, muggy weather. This disease has been found on creeping bentgrass (Agrostis palustris), Kentucky bluegrass (Poa pratensis) and fine fescues (Festuca spp). Disease symptoms are similar to the previous epidemics, Ascochyta leaf blight and Septoria leaf spot, in addition to Pythium blight and Nigrospora leaf spot. Microscopic examination is required to distinguish between these problems. Because warm, wet and humid weather is stressful to the cool season turfgrasses we grow, disease outbreaks are exacerbated by close mowing, applications of herbicides, excessive nitrogen fertilizer, or newly laid sod that lacks good root contact with the underlying soil.

Symptoms of Leptosphaerulina are often confused with the "patch diseases." Large turf areas may become uniformly blighted or appear patchy. Careful examination of individual leaves will reveal a pattern where the grass begins dying back from the tip down to the leaf sheath, unlike other foliar disease problems, which cause scattered leaf spots throughout the blade. Careful examination of the dead and dying leaf blades will reveal the abundant reproductive structures or fruiting bodies (perithecia) where spores are produced that allow the disease to spread. The spores can be observed by handlens or microscope. The spores are produced and released in warm, wet weather and are then blown, splashed, and transported by shoes or lawnmowers to healthy leaves. The spores germinate and penetrate the leaf blades in a film of moisture. The life cycle is repeated, enlarging dead patches as long as the weather permits. Ultimately, this fungus overwinters as perithecia and mycelia in dead grass tissue.

When the first turf epidemic struck, I asked that you think about lawn care as preventive health care. The idea is to prevent problems from occurring so you don't have to treat them. Many of the homeowner samples that had Leptosphaerulina had underlying problems from poorly established sod, to too much shade to greenbug infestations. A healthy lawn can out-compete most weeds, survive insect attacks, and fend off most diseases--before these problems become unsightly. A preventive health care program for your lawn should have the following steps, which can't be repeated often enough:

1.Develop healthy soil
2.Choose a Minnesota- appropriate grass type
3.Mow high, often, and with sharp blades
4. Do not mow wet grass.
5.Water deeply but not too often
6.Dethatch and aerate as needed (now is the time!)
7.Tolerance-for yourself and your lawn. Set realistic goals. Grass is a living organism, not a carpet.
As the hot wet weather abates, so should Leptosphaerulina turf blight. Unfortunately, lawns susceptible to this disease probably have underlying problems that have left them susceptible to Ascochyta or Septoria blight. These problems are expected to re-emerge when the weather cools.

Please check out the new diagnostics web pages at
http://www.extension.umn.edu/projects/yardandgarden/diagnostics/

Birch Catkin Feeders
Jeff Hahn, Assistant Extension Entomologist

Birch catkin feeders Photo credit: Jeff Hahn

It is common to see birch catkin feeders, Kleidocerys resedae, on birch at this time of year. Also known as birch catkin bugs, these insects are true bugs (Hemiptera), belonging to the seed bug family (Lygaeidae). They are small,1/8th inch long, reddish brown insects with the posterior half of the wings being clear. Birch catkin feeders have well developed scent glands and can emit a pungent odor. They feed on the catkins of birch as well as the seeds of other plants, such as azaleas and rhododendrons. Despite this feeding, they do not harm plants. No control is necessary for birch catkin feeders found in the landscape.

Birch catkin feeders are also found indoors occasionally. They fly in through windows or other small cracks or spaces or hitchhike in on clothing or other objects. Fortunately, people usually only see a few at a time and those that do get indoors do not generally live long. They do not hurt people or damage property. Just vacuum nuisance birch catkin feeders or ignore them. They are a short-lived problem that will go away on their own as weather become colder.

Horsehair Worms
Jeff Hahn, Assistant Extension Entomologist

Horsehair worm
Photo credit: Gary Averbeck

Periodically, people find long, very thin worms in their gardens or in their homes during the summer. These creatures are a type of nematode known as horsehair worms. They are pencil lead thin being no more than 1/25 - 1/16 inch in diameter. They are typically several inches long, although they can be growth to be as large as 14 inches. They range in color from white to tan to black.

When immature, horsehair worms parasitize large insects, such as crickets or grasshoppers. When they emerge as adults, they become free-living and can be found on plants. They are also attracted to water and are commonly found in puddles. They originally got their name because when they were found in horse troughs, they resembled strands of horse hair.

Indoors, it is not uncommon to find one in a toilet. This often startles residents as they may imagine that this could be some type of a human parasite. Fortunately, they are harmless to people and pets. No control is necessary for horsehair worms found outside or inside and they should just be ignored.

What To Do About Squash Bugs
Jeff Hahn, Assistant Extension Entomologist

Squash bugs-adults
and nymphs. Photo credit: Eric Burkness

Squash bugs have been very abundant this summer. They are found occasionally in home gardens, feeding on squash, pumpkins, and other curcubits. Squash bug nymphs are wingless and grayish-white with black legs. As adults, they are dark brown and range from ½ to 3/4 inch long.

It is common for squash bugs to congregate on the underside of leaves to feed. They use piercing-sucking mouthparts to feed on plant sap which can cause yellowish spots on leaves, later turning brown. Squash bugs can cause vines to wilt, turn brown, and then black before completely drying up. Although squash bugs do not often injure plants, crops can be severely damaged when squash bug numbers are high.

Control generally is not necessary late in the season. However, if you are seeing high numbers on the foliage, especially if you have a lot of adults, you should try to treat them. Carbaryl (Sevin) and permethrin (Eight) are available to the public for squash bug control, although they are only moderately effective against these insects. Because squash bugs do have a tendency to congregate together, you can try to handpick them or knock the insects off into a pail of soapy water. This will somewhat depend on the size of your garden and how much time you have as this is labor intensive. Later in the season, after the plants dry up, squash bugs can directly attack the fruit and damage them. Watch for that and treat damaging number of bugs.

Adult squash bugs overwinter under debris on the ground. You can reduce the number of squash bugs that survive in your garden and adjacent areas by clearing out accumulations of leaves, plant debris, brush piles, boards and other moist, protected areas that can give squash bugs favorable sites to hibernate.

Open House at the Southern Research and Outreach Center--
"Connecting Agriculture and the Community"

On Thursday, September 12, the University of Minnesota College of Agricultural, Food, and Environmental Sciences welcomes visitors to an Open House at the Southern Research and Outreach Center in Waseca. A special invitation is extended to everyone, both rural and urban folks, to attend the Open House (or, in this case, "open tents"), where many of the University's programs and activities in south-central and southeastern Minnesota will be showcased. The event will run from 2:30 to 8:00 p.m. and is being co-hosted by the UM Extension Service, and the Southern Research and Outreach Center.

The theme, "Connecting Agriculture and the Community" will encourage open communication between all sectors of the population. Displays, tours, one-on-one interactions, demonstrations, and activities will be the primary modes of communicating our story to audiences ranging from farmers and agribusiness to politicians, youth and other citizens in southern MN communities. The displays will highlight specific research, outreach, and extension, show inter-relationships between agriculture and rural and urban communities, and stimulate one-on-one discussions. College administrators and specialists and industry experts will be on hand to answer questions and discuss a variety of topics in an informal setting. From 2:30 to 5:00, several tours will focus on specific agricultural topics with more in-depth discussion. There will be hayrides throughout the day, which will be general "show and tell" tours describing what's happening at the SROC.

The Open House will include activities for all ages and feature farm animals, old and new farm equipment, birds from the UM Raptor Center, and 4H Skillathons. Bring your family to the hog roast (5:00 to 7:00 p.m.), chat with Goldie Gopher, hear Al Batt tell "Bird Stories" (at 5:30 and 7:00 p.m.), or take your chance at winning some prizes. Admission, supper, and all activities are FREE of charge.

While the Open House will allow us to unveil philosophies and new directions, feedback from attendees will help shape future programs. In addition to being a forum for information exchange, we view this as an opportunity to express appreciation for past support received from the community.

The Open House will be held, rain or shine, from 2:30 to 8:00 p.m. on September 12. Supper will be served between 5:00 and 7:00 p.m. For more information, contact your local Extension office or the Southern Research and Outreach Center at 507/835-3620.

For a map and directions go to: http://sroc.coafes.umn.edu/index.html

Editorial Notes

Magic lilies Photo credit: Beth Jarvis

The flowers at left are Magic Lilies, also called Resurection Lily or Naked Ladies, among other namess. They put on a flush of growth in the spring then the foliage dies back. Flower stems emerge from the soil later in summer. They're quite spectacular. The Latin name is Lycoris squamigera.

Hope to meet some of you at the Southern Research and Outreach Center open house!

I'm hot on the trail of authors for pieces acid soil-loving landscape plants and breeding flowers for fragrance. I have a rose breeder colleague who had agreed to write about maintaining rose bushes, kind of a check list of what to do when and how. That will probably be in the next issue. A bit further on the horizon: Integrated Pest Management: just what is it and how to apply to home gardens.

Please feel free to cut and paste any of the articles for use in your own newsletters. All we ask is that you give our authors credit.

Back issues Yard & Garden Line News are on the Yard & Garden Line home page at www.extension.umn.edu/yardandgarden/. Our home page has clickable links to most of the components of the Yard & Garden Line, such as Bell Museum of Natural History, INFO U and the Soil Testing Lab.

Deb Brown answers gardening questions on Minnesota Public Radio's (MPR) "Midmorning" program on the first Thursday of every month at 10 a.m. Katherine Lanpher hosts the program that is broadcast on KNOW 91.1 FM, and available state-wide on the MPR news radio stations.

If you have gardening questions, please call the Yard & Garden Line at (612) 624-4771.

If you would like to receive an e-mail reminder when the next issue of the Yard & Garden Line News is posted to the web, just send an e-mail to: listserv@lists.umn.edu (note: the second E in listserve is omitted), leave the subject line blank, then in the body of the message, type: sub yglnewslist or to unsubscribe, enter: unsub yglnewslist

Happy gardening!

Beth Jarvis
Yard & Garden Line Project Coordinator

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