Yard & Garden Line News Volume 7 Number 15                                                               September 15, 2005

Features this issue: Getting the Jump on Brush and Garden Weeds: An Interesting Moth September Garden Calendar Editorial Notes

Getting the Jump on Brush and Garden Weeds:
Weed Control Products Available to Homeowners for Brush and General Vegetation Control
Bob Mugaas, Regional Extension Educator,
Dr. Patrick Weicherding, Regional Extension Educator
Ron Claussen, Horticulture Assistant

KleenUp Plus glyphosate + oxyfluorfen non-selective, pre-and post-emergence Photo credit: Bonide

There is often a need to control unwanted vegetation in areas other than lawns and turfgrass. Sometimes it is unwanted vegetation in a shrub bed. At other times it might be unwanted vegetation growing along side a garage next to the driveway or alley. It might also be those undesirable tree saplings growing up and into our fences or utility wires. Whatever the situation, there are instances where removing unwanted vegetation from non-turfgrass areas is desired, if not required.

There are a number of very effective products available to home owners for brush and general vegetation control. However, because they can be very effective at killing all the vegetation in an area, it is extremely important that they be used correctly and judiciously. It is not uncommon to hear of situations where these products have been used and desirable surrounding vegetation has also been injured (if not killed) even when the materials were thought to have been applied properly.

The remainder of this article will focus on brush and general vegetation control around the home using commonly available herbicides at retail garden product outlets. This article will not discuss the products available in the commercial sector for brush control and general vegetation management. (For a review of general herbicide terminology and application, see the Yard and Garden Newsletter for July 1, 2005) http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-July0105.html#lawncare .

Preemergence and Postemergence
The concepts of preemergence and postemergence application were previously discussed in the Yard and Garden Newsletter from July1, 2005. Nonetheless, it is important to keep in mind that preemergence herbicides target germinating weed seeds and seedlings prior to their emergence from the ground. Post emergence herbicides target those plants that have already emerged from the ground and are readily visible.

It is common for brush and general vegetation herbicides to contain both postemergence and preemergence materials. The purpose of these combination products is to control existing vegetation as well as prevent emergence of new seedlings. Examples include glyphosate with dithiopyr (Roundup Extended Control) and glyphosate with oxyfluorfen (Ortho Season Long Grass and Weed Killer).

Weed Impede selective preemergence Photo credit: Monterey

Selectivity vs. Non-selectivity
Herbicides are generally developed to either remove certain kinds of plants from other kinds of plants or to kill all of the vegetation in an area. For example, a selective herbicide would kill unwanted grasses growing in a perennial flower garden without harming the desirable perennials. Another example of selectivity would include killing broadleaf weeds such as plantain, clover or dandelions while not harming existing lawn grasses. In contrast, a non-selective herbicide could be used to kill all of the vegetation growing in an area prior to planting that area into a new flower garden. Non-selective herbicides can also be used to kill any unwanted vegetation growing in sidewalk or driveway cracks or along fence lines.

When non-selective herbicides are used around desirable plants, it is extremely important that the desirable plants be protected from any material getting onto their foliage or into their roots. As the term implies non-selective means that the material is not going to be selective in which plants it effects. Glyphosate, originally marketed as Round-up by the Monsanto Corp., is a very common non-selective herbicide used for many different weed control purposes. The drawback of glyphosate is that it destroys only those plants that are up and actively growing. That is, it has no soil activity to prevent seeds from germinating and beginning to grow. Of course, once emerged from the soil and actively growing they are susceptible to subsequent glyphosate applications as well as other non-selective weed control materials.

Non-selectivity plus
In recent years, it has been desirable to not only control the existing vegetation in an area but prevent new plants from getting established. While glyphosate as well as other non-selective materials (e.g., glufosinate-ammonium, diquat bromide), were good at destroying existing vegetation, they are unable to prevent new plants from getting started in an area once the original vegetation has been knocked down. Thus, repeated applications were often necessary during the growing season to keep an area free of plant growth.

Newer formulations of glyphosate as well as other non-selective materials have been combined with other herbicides to provide season long control. Depending on the formulation, these products can be used in landscape beds or used to treat non-landscape areas where the original vegetation needs to be killed off and the area needs to remain clean for an extended period of time. In most of these combinations, the non-selective material has been combined with a preemergent material to provide that 'season-long' control advertised on the label.

A down-side to using combination products with preemergence control is the need to treat the entire area to uniformly distribute the preemergence material. With non-selective materials you may only need to treat a few individual weeds or small, limited areas of weeds. The point is, a non-selective material combined with one of the pre-emergent products may result applying a lot more non-selective material on the area than is needed or necessary.

Occasionally post-emergence non-selective products are combined with post-emergence selective materials. Examples include glyphosate with triclopyr (e.g., Roundup Poison Ivy & Tough Brush Killer Plus) and diquat bromide with fluazifop-p-butyl (e.g., Spectracide Systemic Grass & Weed Killer). This is often done to enhance the control of certain difficult to control weeds (e.g., poison ivy). In other cases it may be used to broaden the spectrum of effective control of a non-selective product (e.g., diquat bromide with fluazifop-p-butyl.) In the latter example, the product is designed to provide non-selective control plus improved grassy weed control.

Persistence vs. non-persistence
Non-selective herbicides come in two broad categories of effects: those that kill everything presently growing on a site but provide no lasting prevention of weedy regrowth and those that kill everything currently growing on a site plus they provide some longer lasting control of weedy regrowth. It is important to consider how long some of these materials inhibit the regrowth of vegetation in that area. If you are planning any sort of replanting or lawn seeding, then be sure the product you choose will not be around to interfere with that new planting. Combinations that include any of the current preemergence products will likely interfere with any turfgrass reseeding to be done, even if it is several months to a year later.

Products advertised to provide season long vegetation control are usually designed for quick knockdown of weeds followed by long term persistent soil residual to prevent weeds from returning for several months or longer. These materials may consist of various materials combined with glyphosate or other non-persistent selective herbicides. Examples include: glyphosate + imazapyr (Ortho Ground Clear - Complete Vegetation Killer), glyphosate + oxyfluoren (Ortho Season-Long Grass and Weed Killer) or diquat bromide + prometon (Spectracide Season Plus Grass and Weed Killer and Preventer). Prometon and sodium chlorate can be found as single ingredients in some products (e.g., Spectracide Total Vegetation Killer (prometon), Fertilome Vegetation Killer (sodium chlorate)). While very good results can be achieved, it is important to follow label use directions very carefully. In general, they should not be used in and around other landscape plants due to their potential for causing injury or death to those plants as well as the target weeds. Many of these total vegetation killer products can be carried by water into the soil profile and may be taken up by roots of nearby sensitive trees and shrubs or the roots of trees and shrubs may grow into areas that have been treated with these persistent herbicides.

It is always important to read product label directions and precautions. This is especially important when using any of the products labeled for general vegetation control. The directions will usually include staying away from desirable plants as the contents can cause severe injury and death if taken up by root systems or inadvertently applied to the foliage either through direct contact or spray drift. Because these products are designed to provide season long control of all vegetation, you usually won't be able to replant into these areas for at least a growing season and perhaps not even the following season. Again, always read directions for use and observe any precautions noted on the product label before applying these materials anywhere in the landscape!

Vine-X triclopyr Photo credit: UPM Corp.

Some special cases
Poison ivy and other woody brush control
Brush killers are not necessarily non-selective herbicides. In the table, you will note that triclopyr (in a more concentrated form than used in lawn applications) is often the single ingredient found in many brush control products.

Triclopyr is a selective, broadleaf weed control herbicide. It will have little to no effect on grass plants or sedges. If you choose to use products where glyphosate is combined with triclopyr, you will be able to destroy grassy plants as well as broadleaf plants, even broadleaf plants not controlled as well with glyphosate alone. Hence, choose your product carefully such that you do not kill off desirable vegetation along with the weeds. Depending on the particular plant material, repeat applications may often be necessary to achieve complete control. Generally, larger more mature plants may require more applications than younger, more succulent plants of the same species.

In some instances, combination products of typical lawn herbicides are formulated and packaged as woody plant herbicides. An example is Bonide's Poison Oak and Ivy Killer that contains 2,4-D, MCPP and dicamba. Since these materials are also designed for broadleaf control in turfgrass, they can be effective on other broadleaf herbaceous and small woody plants in non-turfgrass areas. However, poison ivy often occurs in and among other desirable woody landscape or forest trees and shrubs. The herbicide dicamba is known remain active in the soil for several weeks to a few months. It is also quite mobile in the soil where it can contact and be taken up by nearby roots of non-target plants sharing the same soil root zone. (Keep in mind that the fine, fibrous roots of many woody plants are concentrated in the top 12 inches of soil with many in the top 2 inches and that roots systems extend far beyond the drip line, sometimes as much as 3 times the spread of the branches). That doesn't make the product bad or good, it simply serves to illustrate the need for careful selection of weed control products so as to minimize potential injury to other plants and/or the environment.

Non-selective soap salts for moss and algae control
Frequently, soap salts (potassium and ammonium salts of fatty acids) are packaged and sold as moss and algae killers (e.g., Bonide's Moss Max, Concern Weed, Algae and Moss Killer, Safer Brand Moss & Algae Killer and Surface Cleaner). Potassium salts of fatty acids have also been formulated and packaged as a non-selective weed control product.

Soap salts are believed to interfere with normal cell membrane functioning ultimately leading to the destruction of plant cell integrity and death of the affected tissue. They are not translocated in the plant and hence are considered to be contact herbicides. That is, they only affect the tissue contacted by the herbicide. Usually, these products are not intended for use on lawn areas. Rather they are used for moss and algae control in bare soil situations, mulched landscape beds, concrete paver and patio surfaces, etc. In the past, there have been formulations labeled for moss and algae control in lawns. While there may still be some available, always check the label for where a specific product should and should not be used.

Organic non-selective materials
Recently, various organic oils and acids have been formulated into non-selective herbicide products. Example ingredients include citric acid, acetic acid, garlic oil, clove oil and sodium lauryl sulfate. Again, they can be effective for controlling weeds in non-turfgrass areas as they will injure or kill turfgrass as well. In general, these materials have a disrupting affect on plant cell membrane integrity and function but are not translocated in the plant. That is, they have no systemic action in the plant and hence only affect the tissue directly contacted by the herbicide.

Young seedlings and small immature plants are the most vulnerable to being destroyed by these products. Larger, mature plants as well as perennial plants may need several applications to kill the entire plant. Since they are contact herbicides, it is important to get thorough plant coverage when treating weeds. That usually means spraying the plants until thoroughly wet or until runoff from plant surfaces is observed. This kind of coverage is much easier to achieve on small, immature plants. Some of the ingredients will act as a 'sticking' agent thus helping improve contact of material with the plant. Perennial plants such as dandelion that have their growing points positioned (and therefore protected) beneath the soil surface will need repeat applications to achieve complete kill. The same repeat application strategy would also be true for perennial grassy weeds.

Following is a listing of the most commonly encountered non-selective herbicide choices for brush and general vegetation control available to home owners at various Twin City garden product outlets. One last time, to avoid misuse and misapplication problems with any of these products always read and follow product label directions exactly as printed!

The information given in this publication is for educational purposes only. References to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the University of Minnesota Extension Service is implied.

Brush and Garden Herbicides

Product	Sel.	Non.sel	Pre-em.	Post-em.	Active ingredients
Abby Ground Force Organic Herbicide	.	x	.	x	citric acid + garlic extract
Ace Weed and Grass Killer	.	x	.	x	glyphosate
All Down Organic Weed & Grass Killer	.	x	.	x	citric acid + garlic
Bayer Advanced Power Force Brush Killer Plus	x	.	.	x	triclopyr
Bonide Kleenup Plus - Grass & Weed Killer	.	x	x	x	glyphosate + oxyfluorfen
Bonide Moss Max (Kills Algae, Moss, Lichens)	x	.	.	x	Potassium soap of fatty acids
Bonide Poison Oak & Ivy Killer	x	.	.	x	2,4-D + MCPP + dicamba
Concern Weed, Algae and Moss Killer	.	x	.	x	ammoniated soap of fatty acids
Ferti-lome Brush and Stump Killer - controls woody plants & broadleaf weeds	x	.	.	x	triclopyr
Ferti-lome Over-the-Top Grass Killer	x	.	.	x	fluazifop-p-butyl
Fertilome Vegetation Killer	.	x	.	x	sodium chlorate
Green Thumb Weed and Grass Killer	.	x	.	x	glyphosate
Greenview Preen Garden Weed Preventer (non-turf use)	.	.	x	.	trifluralin
Greenview Preen 'n Green - Prevents weeds and fertilizes (non-turf use)	.	.	x	.	trifluralin
Greenview Preen Weed and Grass Preventer (hose-end application)	.	x	.	x	glyphosate
Greenview Preen Weed Preventer Plus Fertilizer (non-turf use)	.	.	x	.	trifluralin
Hi-Yield Kill-Zall Weed and Grass Killer	.	x	.	x	glyphosate
Maxide Weed & Grass Killer	.	x	.	x	glyphosate
Monterey Weed Impede for annual grasses and broadleaf weeds (non-turf areas)	x	.	x	.	oryzalin
Ortho Basic Solutions Total Vegetation Killer	.	x	x	x	prometon
Ortho Brush-B-Gon - Poison ivy, Poison Oak & Brush Killer	x	.	.	x	triclopyr
Ortho Grass-B-Gon Garden Grass Killer	x	.	.	x	fluazifop-p-butyl
Ortho Ground Clear Complete Vegetation Killer	.	x	x	x	glyphosate + imazapyr
Ortho Season-Long Grass and Weed Killer	.	x	x	x	glyphosate + oxyfluorfen
Ortho Triox - Total vegetation killer	.	x	x	x	glyphosate + imazapyr
Roundup Concentrate plus	.	x	.	x	glyphosate + diquat dibromide
Roundup Extended Control	.	x	.	x	glyphosate + dithiopyr
Roundup Plus - Weed & Grass Killer (ready to use)	.	x	.	x	glyphosate + pelargonic acid
Roundup Poison Ivy & Tough Brush Killer Plus	.	x	.	x	glyphosate + triclopyr
Roundup Super concentrate	.	x	.	x	glyphosate
Roundup Sure Shot Foam	.	x	.	x	glyphosate
Safer Brand Moss & Algae Killer & Surface Cleaner	x	.	.	x	potassium salt of fatty acids
Spectacide Season Plus Grass & Weed Killer & Preventer	.	x	x	x	prometon + diquat dibromide
Spectracide Total Vegetation Killer	.	x	x	x	prometon
Spectracide Triple Spike Grass-Weed-Root	.	x	.	x	diquat dibromide + fluazifop-p-butyl + dicamba
St. Gabriel Laboratories Burn Out II - Weed & Grass Killer	.	x	.	x	clove oil + sodium lauryl sulfate
St. Gabriel Laboratories Moss Killer	x	.	.	x	clove oil + sodium lauryl sulfate
Vine-X Vine & Brush Control	x	.	.	x	triclopyr
Spectracide Systemic Grass & Weed Killer	.	x	x	.	diquat dibromide + fluazifop-p-butyl

An Interesting Moth
Jeffrey Hahn, Assist. Extension Entomologist

Velleda lappet moth Photo credit: Ron Hofstrand

An interesting family of moths that we occasionally encounter is the Lasiocampidae, known as the tent caterpillars and lappet moths. The two most common species in this group with which we are familiar are the eastern tent caterpillar and the forest tent caterpillar.

The eastern tent caterpillar constructs webbing in the forks of branches in cherry and other fruit trees during spring where it lives gregariously, i.e. in nonsocial groups. The forest tent caterpillar, despite its name, doesn't construct much of a web but is known for its extreme population fluctuations. Unlike the eastern tent caterpillar, it not found in gregarious groups. Both caterpillar are blue with white markings and are fairly hairy. People are not likely to see the brownish adult moths that they turn into.

However, people are less knowledgeable about the lappet moths. They are named because the caterpillars possess a fleshy lobe or lappet on each segment along its abdomen. It is at this site that clumps of long hairs protrude from their body.

A common lappet moth that is active now is the velleda lappet moth also known as the large lappet moth, Tolype velleda. This moth is common throughout the eastern U.S. and southern Canada. The velleda lappet moth is moderate-sized with an average body length of about 3/4 inch and a wingspan of 1 1/4 to 2 1/2 inches. The wings range from light to dark gray with white veins. A distinguish characteristic is the white colored band near the margin of the forewings. This moth holds its wings roof-like when at rest.

Both the legs and body are so hairy that they look furry. The head and the thorax are white while the abdomen is gray or black. Watch for a distinctive wedge-shaped black area on top of the thorax to help identify this moth. When resting, this moth places its first pair of legs forward and its second pair of legs straight out at about a 90o angle. This is actually a typical position for lappet moths in general.

The valleda lappet moth overwinters in the egg stage. The larvae hatch in June through August. The larvae, which grow to be about 2 1/2 inches long when fully grown, have a grayish body which blends in very well with the bark of the branches. These caterpillars feed on the leaves of a variety of hardwood trees, including apple, ash, aspen, birch, cherry, elm, oak, and plum. Despite their feeding, they are rarely, if ever, are a pest of these trees. They pupate at the end of the summer and then the adult moths are active from late August through October.


If you are out at night during September and October during mild weather, watch for this attractive moth around yard lights and nearby sites. It is an interesting and intriguing insect to find.

Get the low down on this month's insect pests at Insects http://www.extension.umn.edu/projects/yardandgarden/EntWeb/Ent.htm

September Garden Calendar
Compiled from conversations with Bob Mugaas and Patrick Weicherding, Regional Extension Educators

Heath Aster Aster ericoides Photo credit: Beth Jarvis

Trees and Shrubs:
Water, water, water--especially new trees and shrubs for first five years. The soil should be damp about 6" below the surface.

Leaves from trees that had foliar diseases such as anthracnose, apple scab, etc. should disposed of rather than composted. Compost piles do not heat enough to kill disease organisms.

It's safe to prune oaks and elms now though dormant season is the safest time.

You can still plant trees that are in containers or were balled and burlapped last spring. It is too late to dig trees up and move them. Do not amend soil or add fertilizer to the planting hole.

Lawns:
Now is an ideal time to control common broadleaf perennial weeds--clover, plantain, dandelions. General purpose herbicides work fine for most broadleaf weeds but if you're battling clover and creeping Charlie/ground ivy, use a product containing triclopyr. Thanks to cooler temperatures and increased rainfall, weeds are actively growing and will absorb herbicides applied to them.

It's about time to forget lawn seeding. Try to finish it up by mid-September, the 20th at the latest. After that, you'd best wait until late October to early November and try dormant seeding.

Be sure to keep leaves off any newly seeded grass. Seedling grass needs all the light it can get right how.

Make a note of crabgrass infestations so you can treat those spots next spring.

If you've not been blessed with adequate rainfall the last few weeks, you should water your lawn. Much of the state has gotten enough water for grass. One big key to a healthy lawn is healthy plants. Healthy plants will make it through winter with less winter injury.

Keep mowing as long as grass is actively growing. But don't fertilize right now; wait until closer to the end of October, although northern Minnesota, could fertilize a week earlier and southern Minnesota could hold off until the first week of November. Fertilizing now encourages succulent growth that will not harden off before temperatures drop and this will contribute to increasing snowmold next spring. Late season fertilizer is stored as in nitrogen-rich proteins for next spring.

Fruits, Flowers and Veggies
Houseplants that overwintered outside could start moving back indoors. Be sure to wash the vacationing plants well on both tops and undersides of the leaves. Check for tiny white specks, sticky leaves or webbing that could signal a spider mite infestation. Also watch for bits of white on leaf undedrdsides that would be shed skins of aphids or white flies. Keep returning houseplants isolated until you determine they're not infected with insect pests. Small, dark flies could be fruit flies or fungus gnats. If they have red eyes, they're fruit flies.

Amaryllis can also be brought indoors. If you have the space, you don't need to let them go dormant.

It's getting to be time to plant spring flower bulbs. Do you have your bulbs ordered? The should go in over the next 30 days. Tulips can go in later, but daffs, crocus, etc. all need to go in soon. Here's some info on: spring bulbs.

Apples can withstand a light frost so if it dips down into the mid-20s, don't fear. Just keep your toasty warm fingers off them until the ambient temps arise above freezing and the apples warm. Otherwise, you'll leave bruises in the apples. If you're not sure if they're ripe, look at the seeds. If they're dark brown, the apples are ripe.

Watch for sooty blotch or fly speck on apples at harvest. Read more about these fungal problems, favored by temperatures in the 70s, high humidity and frequent rains at: Sooty Blotch and Flyspeck on Apple and Pear.

Editorial Notes

(Asparagus) Fern Potts. Photo credit: Beth Jarvis

Perhaps the pots at left should be dubbed (Aspara)-Gus Potts? There are several creations at the Arboretum Gatehouse.

Recently I spoke with Neil Anderson,the U's mum breeder. He said that the mums currently known as "My Favorite" might be in short supply next year because they have renegotiated the propagation contract and changed companies. The mums will be more widely available after the change takes place but they might be in short supply in the interim. It takes a while to build up inventory. The current propagator is selling off inventory and the mums are available at Home Depot, among other places. Neil said the mums might have to be renamed as they won't be "My Favorite". Neil said they will be releasing four new colors. There will be more info on the latest on the mums published in Y & GL News later this winter.

For October 1, Patrick Weicherding will write about on-going research at the U that's evaluating whether butterflying, scoring or teasing apart circling roots in container-grown trees makes a difference in the establishment of trees. With the October issue, we return to monthly publication, around the first of the month. For November 1, Patrick will return with an article on how to kill trees. Buckthorn will be the only thing the woods with leaves so it will be easy to spot it and kill it.

By Nov. 1, we should be able to tell you all about the latest apple release from teh U's apple breeding program.

Prior to spring perennial ordering, Bob Mugaas will provide the data from the two year perennial evaluation program that he, Janna Beckerman and a host of Master Gardeners conducted.

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/.

Deb Brown answers gardening questions on Minnesota Public Radio's (MPR) "Midmorning" program on the first Friday of every month at 10 a.m. The program is broadcast on KNOW 91.1 FM, and available state-wide on the MPR news radio stations. (Scroll down for map.)

For plant and insect questions, visit http://www.extension.umn.edu/askmg. Thousands of questions have been answered, so try the search option in the black bar at the top left of the board for the fastest answer.

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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