Posts tagged trees

The deadly juglone of black walnut trees

The following is by Linn County Master Gardener, Claire Smith:

    The seeder wagon is in place.  The lawn mower towed it out of the shed down to the water way and then with two planks and my favorite son’s strong back we pushed and pulled it to the other side of the ditch.  With the addition of an old wire garden gate staked behind a sapling, a hand pump from my parent’s former home and a rock lined pseudo fire pit filled with Petunias that were on the end-of-season sale, the area reflects the peaceful primitive atmosphere I was striving for.  This is the area I mentioned in an earlier blog that became inaccessible to mow due to last year’s flood.  Hosta, native grasses and prairie perennials will grace the space next year.  We continued our zeroscaping to include a part of the road ditch that I learned is also impossible to mow after the mower and I suffered a close encounter with the culvert.  Now that waterway is filled with large rocks and what was a sloping grassy space is mulched. 

            Hosta will ring the two Black Walnut trees in the roadway ditch.  Hosta is a plant of choice there because I have some that need transplanting and they are not sensitive to Juglone, a chemical secretion from Black Walnut Trees. 

             Discovered in the 1880s, Juglone is produced in the fruit, leaves, branches and root system of several trees with Black Walnuts exhibiting the highest concentration.  The greatest intensity in the soil exists within the tree’s drip line, on an average 50 ft. radius from the trunk of a mature tree.  Plants susceptible to Juglone display yellowing leaves, wilting and eventual death.  Plants sensitive to Juglone include Peonies, Hydrangea, Asian Lilies, and Lilacs.  There are multiple choices that will withstand close proximity to Walnut trees such as most grasses, Phlox, Sedum, Daylilies, Iris and Hosta.

            Now my challenge is to determine plants that are not only resistant to Juglone, but also to the deer population in this neighborhood.  Unfortunately, Hosta is one of the critters’ favorite choices.  They have already decimated the Hosta and Bee Balm in the ditch on the other side of the lane.  A great winter  pastime will be comparison shopping perennials and grasses that are both deer and Juglone resistant as well as low maintenance for those landscapes. 

             I actually enjoy mowing.  And I like the challenge of creating and maintaining flower beds, but the  simple clean lines of zeroscaping does appeal to me.  A few plants and shrubs easily embellish the area without overstating the purpose of low maintenance.

Advertisements

Leave a comment »

Backyard Abundance tour Saturday

Toni and Jake DeRyke home (photo, Backyard Abundance)

Toni and Jake DeRyke home (photo, Backyard Abundance)

Information on the following Backyard Abundance event came from Fred Meyer: 

Decades of steady care by Toni and Jake DeRyke, 2101 Muscatine Ave., Iowa City, have led to a peaceful and orderly yard filled with beautiful flowers, tranquil shade gardens and an abundance of food. The yard will be open to view from 3-5 p.m. Saturday (June 27, 2009.)

 The DeRykes strive to keep their environmental impact low while also saving money:

  • Growing their own food eliminates the carbon dioxide that would otherwise be emitted to transport food to their home.
  • Rain barrels capture free rainwater for their garden, reducing the need for energy-intensive purified tap water.
  • Steady supplies of low-cost reclaimed building materials are frequently acquired from the Habitat for Humanity ReStore.
  • Trees shade their home, reducing energy bills and providing bird habitat.

 Toni and Jake reflect our growing efforts to think globally and act locally; and it does not get more local than your own backyard.

 Parking for their event is available on 3rd Avenue, on the west side of their home.

 For more information, see: http://www.backyardabundance.org/events.aspx

Comments (1) »

Your questions: tree talk

Readers have trees on their minds this month.

Dale, who lives in southeastern Wisconsin, submitted the following question: I have a beautiful Walnut tree but it has been sprouting branches near its
bottom and just does not look right.  Can I prune them now ? If so what angle? And should I put something on the exposed ends? Some of the branches are approx. an inch in diameter. I surely don’t want to harm my tree!

Teresa submitted the following: I am in need of help to get rid of the seedlings from my pear tree. I need to know when and how to manage them as I have a flowerbed under my tree. I did not put these in but inherited them from the previous owner. They are a nightmare to deal with. Thank you for your help.

If you have advice for Dale or Teresa, leave a comment below.

Leave a comment »

Japanese beetles are back

They’re back.

Japanese beetles

Japanese beetles

I spotted the first Japanese beetle of the season yesterday on my raspberry bushes. I went to check one of my rose bushes and sure enough, there was another one, sucking the life out of a beautiful pink bud. Unfortunately, both got away.

The beauty of these copper-colored beetles belies the devastation they wreak. Adult Japanese beetles feed on more than 300 types of plants – turning leaves into lacy skeletons. As larva, the white c-shaped grubs feed on turf grass roots.

I’ve heard some people have luck with the Japanese beetle traps that can be found at garden centers. Others say the traps just lure more beetles into your yard. When I see just a couple of the bugs, I use the squish method, but as they become more numerous, I’ll try to control their numbers with soapy water.

Take a small bucket with water and dish detergent – any kind will probably work – and knock the beetles off the plants into the bucket. The beetles are more active at certain times of day and will fly off. Othertimes, they do a drop and roll, which is the best way to get them to fall into the bucket. Early evening seems to be the time when they are more sluggish and easier to catch that way. Obviously, if you are growing crops that the beetles are attacking, such as grapes (another favorite,) you’re going to need a different method of control. They also favor certain trees, but supposedly they don’t kill the trees as do pests like the emerald ash borer. I also wonder what they will ultimately do to the monarch butterfly population, as Japanese beetles devastate the monarch’s food source, milkweed.

Since they make my top 10 bad bugs list, the Japanese beetle and different control methods can be found in several posts on this blog. Just use the search box at the right to find more from city arborist Daniel Gibbons, master gardeners and others on this foreign invader.

Leave a comment »

Getting ready for Japanese beetles

   I’ve been keeping a careful watch for Japanese beetles in my garden and enjoying my roses before the pesky beetle begins its annual invasion. The city of Cedar Rapids sent out the following today, (June 8, 2009) which made me wonder if Japanese beetles had already emerged. City arborist Daniel Gibbons, who wrote the article, assured me that he hadn’t seen any. Yet.

Japanese beetles

Japanese beetles

But, they will arrive, worse in some areas than others. If you haven’t seen this foreign invader yet, be grateful. Whether or not you have, read the following from Daniel Gibbons to learn more:

Japanese beetle has become one of the most destructive and frustrating pests for gardeners, farmers, and green industry professionals.  A transplant from Japan during the early 1900’s, Japanese beetle (Popillia japonica Newman) populations have enjoyed explosive growth across the East and Midwest.  Damage inflicted by various stages in the beetle’s life cycle can be severe to turf grasses, agricultural crops, and over 300 ornamental trees and landscape plants.  The USDA estimated in 2007 that control measures alone cost over $460 million.

Success of the non-native Japanese beetle can be primarily attributed to a lack of natural predators and a supportive climate and food source.  Although eradication is not feasible, successful management leading to reduced populations will minimize pest damage.  Those who succeed in managing Japanese beetle do so by gaining local cooperation, using an integrated approach to natural and chemical control, and by shrewdly selecting plant material when designing a garden or landscape.

Local cooperation is critical because of Japanese beetle mobility.  Despite the best efforts of one property owner, beetles from neighboring yards are usually a significant problem.  Success will increase if adjoining neighborhoods and property owners cooperate with sound management techniques.

Integrated Pest Management (IPM) is simply the use of multiple control techniques to reduce the comprehensive use of pesticides.  When properly used, IPM creates a healthy biotic environment in which populations of undesirable pests are reduced over time by the introduction of predatory elements, resistant plants, and targeted use of pesticides when necessary. 

Natural predators of Japanese beetle include microscopic nematodes (Heterorhabditis bacteriophora), naturally occurring soil bacteria (Bacillus thuringiensis), and the spores of Bacillus popillae (referred to as “Milky Spore”).  The success of these and other products can be effective, but depends on adherence to application and storage directions, climatic and soil conditions, and the presence of other pesticides or chemicals which may be harmful to these living organisms.  Products such as Milky Spore will become more effective over the span of several years when the bacterium has had time to establish.

Application of pesticides may be used to reduce heavy infestations, but should be performed by competent and trained applicators.  Some chemicals may only be used by licensed pesticide applicators.  Considerations in choosing insecticides to control Japanese beetle will include application method, seasonal timing, location, type of plant material being protected, and the presence of sensitive environment features such as waterways.  Assistance in choosing the latest formulation of pesticide for a particular site may be obtained from local garden shops or government extension agencies.

Finally, avoiding plants and trees that are susceptible to Japanese beetle is the best method to reduce the pest’s impact on a particular landscape or garden.  Keeping landscape plants healthy will also increase resistance.  The following trees are specifically targeted by Japanese beetle: Linden, Birch, Norway and Japanese maple, pin oak, beech and horse-chestnut.  Trees that show resistance to the beetle include hickory, red maple, tulip poplar, dogwood, northern red oak, pine, spruce, arborvitae and hemlock.  Resistant herbaceous plant groups include: Columbine, ageratum, coreopsis, coral-bells, showy sedum, hosta, and forget-me-not.  Herbaceous plants to avoid in areas where beetle populations are high include: rose, hibiscus, evening primrose, clematis, sunflower, peony, zinnia, asparagus and morning-glory.

Despite recent challenges with Japanese beetle, thoughtful management can reduce the impact to community gardens and landscapes.  Education, cooperation and savvy IPM practices will also reduce the impact on our pocketbooks, while promoting a healthy and vibrant growing season.

More information on Japanese beetle may be obtained through the following online sources: “Managing the Japanese Beetle: A Homeowner’s Handbook”    http://www.aphis.usda.gov/publications/plant_health/content/printable_version/JB3-07.indd.pdf

Iowa State University – Iowa Insect Information Notes http://www.ipm.iastate.edu/ipm/iiin/node/125

Leave a comment »

Emerald Ash Borer larva found in Iowa; UPDATE: ash tree protection

An infestation has not been confirmed, but officials are scouting northeast Iowa after an Emerald Ash Borer larva was found.  Iowa State University extension sent out tips today (June 5, 2009) on protecting your ash trees. See those tips at the end of the following info that was released Thursday (June 4, 2009) from the Iowa Department of Agriculture and Land Stewardship:

ELKADER – Efforts to scout portions of northeast Iowa for the presence of emerald ash borer (EAB) have intensified following the submission of an EAB larva to the Iowa Department of Natural Resources.  The larva was reportedly from Clayton County, however no additional EAB larvae have been found and no signs of infestation have been spotted in the immediate area. As a result, an EAB infestation cannot yet be confirmed.

 The EAB larva was reportedly found in a small sentinel tree at the Osborne Welcome and Nature Center in Clayton County.  The tree was established by the Iowa Department of Natural Resources with funding from the U.S. Forest Service.

 Officials from the Iowa Department of Agriculture and Land Stewardship, DNR and Iowa State University Extension have been conducting extensive scouting of the tree and around the Osborne Center this week.

 The Osborne Center is located approximately five miles south of Elkader and approximately 60 miles southwest of where an EAB infestation was confirmed in Wisconsin in early April of this year.

 Additional experts are returning to the area in the upcoming weeks to place traps in the immediate and surrounding area, during the next one-two weeks, to determine if an EAB infestation is present in the area.

 Officials from the Iowa Department of Agriculture and Land Stewardship, the Iowa Department of Natural Resources and Iowa State University Extension will also be hosting two public meetings on Tuesday, June 16th at the Osborne Center about this discover.  The officials will meet with timber industry representatives 1:00 p.m. and then host a public meeting for residents that evening at 6:30 p.m.

 EAB detection in Iowa was the result of collaborative team members looking for this pest since 2003. From visual surveys, to sentinel trees, to nursery stock inspection, to sawmill/wood processing site visits, and hundreds of educational venues [meetings, phone calls, written correspondence, media interviews, and 1-on-1 conversations], the Iowa EAB team has been working to spread the word about this invasive insect and to protect the state.

 The Emerald Ash Borer (EAB) is native to the Orient, and was introduced in the United States near Detroit, Mich. in the 1990s.  EAB kills all ash species by larval burrowing under the bark and eating the actively growing layers of the trees.

Emerald Ash Borer

Emerald Ash Borer

 Iowa State University Extension will issue a separate news release providing EAB management recommendations.

 The metallic-green adult beetles are a half inch long, and are active from May to August.  Signs of EAB infestation include one-eighth inch, D-shaped exit holes in ash tree bark and serpentine tunnels packed with sawdust under the bark.  Tree symptoms of an infestation include crown thinning and dieback when first noticed, epicormic sprouting as insect damage progresses, and woodpecker feeding.

 “We started our scouting efforts in the park where the larva was reportedly found and are spreading outwards. We have a five-mile radius grid that is going to be thoroughly investigated for any additional signs of EAB,” said Robin Pruisner, State Entomologist with the Iowa Department of Agriculture and Land Stewardship.

 If an infestation is ultimately confirmed in Iowa, officials have a plan is in place to help stop the spread of EAB that would include a quarantine prohibiting the movement of hardwood firewood, ash nursery stock, ash timber or any other article that could spread EAB from infested areas.

 Clayton County is one of the top producers of forest products in Iowa.  The county has an estimated 66 million woodland trees and an estimated 6.6 million ash trees.

 EAB has been killing trees of various sizes in neighborhoods and woodlands throughout the Midwest. Ash is one of the most abundant native tree species in North America, and has been heavily planted as a landscape tree in yards and other urban areas. According to the Iowa DNR, Iowa has an estimated 58 million rural ash trees and approximately 30 million more ash trees in urban areas.

 The Iowa Emerald Ash Borer Team includes officials from the Iowa Department of Agriculture and Land Stewardship, Iowa State University Extension, the Iowa Department of Natural Resources, USDA Animal Plant Health Inspection Service (APHIS) and the USDA Forest Service.

 The movement of firewood throughout Iowa and to other states poses the greatest threat to quickly spread EAB.  Areas currently infested are under federal and state quarantines, but unknowing campers or others who transport firewood can spark an outbreak.  As a result, officials are asking Iowans to not move firewood and instead buy wood where they are staying and burn it completely.

 To learn more about EAB please visit www.IowaTreePests.com or for additional resources Iowans can visit http://www.iowadnr.gov/forestry/eab/index.html

Ash leaf damage/ Deb McCullough, Michigan State University

Ash leaf damage/ Deb McCullough, Michigan State University

From ISU Extension:

AMES, Iowa — The presence and new discovery of emerald ash borer (EAB) in states adjacent to Iowa has increased interest in this exotic, invasive insect and what Iowans can do to protect ash trees (Fraxinus species) on their property.

ISU Extension is collaborating with Iowa state regulatory agencies and local officials to prevent introduction of EAB into Iowa and limit its spread. For a full list of EAB detection and education activities, please visit our website at: www.extension.iastate.edu/pme/EmeraldAshBorer.html

Treatment options to protect ash trees from this destructive pest are available but careful and thoughtful analysis is needed to circumvent spread of false information and excessive and needless use of insecticides. Forest, horticulture, and insect specialists with Iowa State University Extension have developed a guide that outlines your management options against EAB.

The first step for many is confirming that you do have an ash tree. Only ash trees are susceptible to EAB attack, but all species and cultivars of ash trees are at risk.

Second, is the ash tree growing vigorously and in apparent good health? Trees must be healthy and growing for treatments to be effective. Ash trees with mechanical injuries, loose bark, thin canopies, and those growing on poor sites (limited rooting area, compacted soil or other stresses) are not worth treating. If your ash tree looks healthy and is important to your landscape, then preventive treatment options may be considered.

Insecticide control measures against EAB should not be used unless you live within 15 miles of the confirmed EAB infestation. Treatment outside this risk zone is not advised. Protecting ash trees with insecticides is a long-term commitment. Most treatments will need to be reapplied annually or twice per year for an indefinite number of years to protect the tree. With that in mind, most homeowners would be ahead to remove and replace susceptible trees.

Treatment timing is critical and must be matched to insect life cycle. After mid-June treatment is not recommended because it takes time for the systemic insecticide to be distributed within the tree (from 2 – 8 weeks depending on the application method).

Ash tree damage from Emerald Ash Borer/ Mark Shour, ISU Extension

Ash tree damage from Emerald Ash Borer/ Mark Shour, ISU Extension

The recommended time of application is early to mid April each year. If the tree is large (more than 16” diameter), a treatment in early fall is also suggested. So the next window for treatment for trees in Iowa would be mid to late September 2009.

A new Iowa State University Extension publication, PM 2084, Emerald Ash Borer Management Options,  will be available on June 12. The North Central Region Integrated Pest Management Center’s Insecticide Options for Protecting Ash Trees from EAB was issued in May 2009. Both can be found at www.extension.iastate.edu/pme/EmeraldAshBorer.html

Comments (3) »

Bugged by bugs?

  

Japanese beetles

Japanese beetles

 Spring in Iowa is too fleeting. Rare are those 70-degree days with cool nights before the air explodes with humidity and bugs begin their annual invasion. I can look at healthy green potato plants today and know that in a week or so the Colorado potato beetle will begin its defoliation quest. Same is true of the lush rose bushes that succomb ever earlier to the dreaded Japanese beetle, a copper-colored foreign invader.

   Because of the devastation they wreak on my plants, the Japanese beetle and potato beetle rank number one and two on my list of “bad bugs.” I was enjoying my backyard garden last night trying to think of others when a mosquito bit my leg. Mosquitoes= #3.

Colorado potato beetle

Colorado potato beetle

   Here are the others: 4) gnats or whatever those little black bugs are that bite behind the ears. 5) chiggers – not an insect, but larvae of a specific family of mites – the Trombiculidae. If you’ve ever suffered through chigger bites, you’ll know why these are on my list. 6) wasps – I try to leave them alone, but they seem ubiquitous this year and more aggressive – building wherever they take a liking, which includes my back porch and my sons’ club house.  7) ticks – again, not an insect, but my general worry over them keeps me from enjoying the outdoors at times. 8) Ants – luckily we don’t have  fire ants like they do in the south, but they’re just a pain when they decide to come in the house. 9) termites – again a general anxiety thing. 10) Emerald ash borer – not here in Iowa yet, but a preemptive disdain for a foreign invader that will someday devastate our ash trees. 

Emerald ash borer

Emerald ash borer

   What makes your list? I’m sure I’ll think of more, now that our perfect spring days are in the past.

Comments (7) »