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Tuesday, August 25, 2015

EAB now found in Scott County

Jeffrey Hahn, Extension Entomologist

Woodpecker activity on ash is a red flag for
EAB. Photo: Jeff Hahn, UMN Extension
(The following information is taken from an August 25, 2015 news release from the Minnesota Department of Agriculture)

The Minnesota Department of Agriculture (MDA) announced today that emerald ash borer (EAB) was confirmed for the first time in Scott County. The MDA received a call through their Arrest the Pest information phone line (888-545-6684) alerting them to a suspicious ash tree on private property in Prior Lake. An onsite visit confirmed an EAB-infested tree.

Scott County becomes the 10th county in Minnesota to verify EAB, joining Anoka, Dakota, Hennepin, and Ramsey counties in the metro area; Chisago County north of the metro and Fillmore, Houston, Olmstead, and Winona counties in southeastern Minnesota.

Scott County will be put under an emergency quarantine and will eventually join the above counties in a state and federal quarantine. A quarantine helps prevent the spread of EAB by restricting the movement of ash products including ash trees and limbs and all hardwood firewood.

The MDA reminds residents of things to watch for when looking for EAB.

1. Be sure you’ve identified an ash tree. This is an important first step since EAB only feeds on ash trees. Ashes have opposite branching – meaning branches come off the trunk directly across from each other. On older trees, the bark is in a tight, diamond-shaped pattern. Younger trees have a relatively smooth bark.

2. Look for woodpecker damage. Woodpeckers like EAB larvae and woodpecker holes may indicate the presence of EAB.

3. Check for bark cracks. EAB larvae tunneling under the bark can cause the bark to split open, revealing the larval (S-shaped) tunnels underneath.

4. Contact a professional. If you feel your ash tree may be infested with EAB, contact a tree care professional, your city forester, or the MDA at arrest.the.pest@state.mn.us or 888-545-6684.

For more information about EAB, see Emerald ash borer in Minnesota. See also the MDA news release, MDA confirms emerald ash borer find in Scott County.








Friday, August 14, 2015

Yellowjackets are conspicuous now

Jeffrey Hahn, Extension Entomologist

There have been a lot of question about yellowjackets lately. These insects are at their peak numbers now and nests that people didn’t realize were present are now being discovered. While in most cases people are seeing yellowjackets, there is a tendency to call all stinging insects "bees" which can be confusing. Different approaches are taken for control depending on whether yellowjackets or honey bees are present.
A typical yellowjacket.  Note the black and yellow color
 and smooth body. Photo: Jeff Hahn, UMN Extension

The first step is to verify which insect is present. A yellowjacket is about ½ inch long (this can vary some), black and yellow or white, and relatively slender with few hairs. A baldfaced hornet, a type of yellowjacket, is a little larger, about 5/8th inch long, and mostly black. Paper wasps may also be found; they are generally brown with yellow marking, a slender body with long legs and measure from 1/2 to 1 inch long. Honey bees are about ½ inch long brown and black, relatively slender but have more hair.

If you have yellowjackets or paper wasps, there are several options for dealing with them. If the nest is located a reasonably safe distance from where people may be present and the risk of stings is minimal, just ignore them. Eventually, all of the insects in the nest die after hard frosts occur.

If nests are located somewhere where an unacceptable risk of stings occurs, then the nests should be treated (For specific information on treating yellowjacket nests, see Social wasps and bees in the upper Midwest). There have been requests to find someone who can remove and relocate yellowjacket nests. While this can be done with honey bee colonies, it is not possible to relocate a yellowjacket nest. The only options are to ignore or treat them.
Honey bee.  Note the brown and black coloration and fuzzy
body.  Photo: Jeff Hahn, UMN Extension

Honey bees should be tolerated in essentially all circumstances. If honey bees are found, that have been positively identified, an experienced beekeeper may be willing to remove it. Check for one at the bee removal website or on the Minnesota Hobby Beekeepers Association website.

For more information on yellowjackets and bees, see Social wasps and bees in the upper Midwest.

Tuesday, August 11, 2015

Got Rust? Send in a sample

University of Wisconsin Turfgrass Rust Research 


In 2013 the Department of Plant Pathology at the University of Wisconsin – Madison, in cooperation with the Wisconsin Sod Producers Association (WSPA) and Sod Growers of Mid America (SGMA), initiated a series of experiments investigating the reasons behind increases in rust injury to cool-season turfgrass observed over the past several years. The project includes 4 primary experiments:

  • Use of molecular and morphological means to identify rust species associated with turfgrass found in sod production, home lawns, athletic fields, and golf course management from around Wisconsin, the Midwest, and the country.
  • Determination of inherent resistance to the multiple rust species in multiple genetic families of Kentucky bluegrass.
  • Inclusion of varying amounts of tall fescue mixed with Kentucky bluegrass and the impact on rust development.
  • Impact of nitrogen source and fungicide timing on rust development.

As part of the rust species identification project, we are looking for rust samples from your turfgrass! It doesn’t matter what species of grass, and it doesn’t matter what type of turf (sod, golf, home lawn). If you see rust on your turf, please submit it to the Turfgrass Diasnotic Lab for identification using the following simple steps:

  • Pick or cut 5 to 10 turfgrass plants affected by rust from the base of the plant near the soil, including both leaves and stem. Roots do not need to be included.
  • Wrap all plants together in aluminum foil, do NOT wrap in moist newspaper or paper towel.
  • Place wrapped plants in a standard business envelope (4.125 X 9.5 inches), include completed Rust ID Submission Form, affix postage, and promptly mail to the Turfgrass Diagnostic Lab at 2502 Highway M, Verona, WI 53593.
  • Please remember to complete and include the Rust ID Submission Form when submitting the sample. 
  • Not sure if you have rust present on your lawn? Check out our Rust Disease ID page for more information. Still not sure? Submit it anyways and we’ll identify it regardless.

Friday, August 7, 2015

Strawberry root weevils just a nuisance

Jeffrey Hahn, Extension Entomologist

People have been reporting small, dark colored insects in their homes during July and August. A strawberry
Strawberry root weevils are just a nuisance. 
Photo: Jeff Hahn, UMN Ext
root weevil is a pear-shaped, dark brown or black insect with a short snout. It also has rows of punctures on its wing covers. Strawberry root weevils can crawl but they cannot fly.

Identification is very important because in a lot of cases, people have been concerned that these creatures are
ticks. The pair of antennae is a similar length as the legs and gives the appearance that the insect has eight legs. In the past strawberry root weevils have also been sometimes confused for bed bugs.

Strawberry root weevil larvae feed on the roots of a variety of plants, including, arborvitae, spruce, and strawberries. The adults sometimes accidentally enter homes and other buildings. It is common to find them sinks, tubs, basins, and other sources of moistures. They do not cause any damage and are just a nuisance. In most cases, people see only a few weevils at a time

Physical removal is the only necessary control. Strawberry root weevils will eventually go away on their own. For more information, see Home-invading weevils.

EAB found in Chisago County

Jeffrey Hahn, Extension Entomologist

The Minnesota Department of Agriculture (MDA) announced on Thursday, August 6 that emerald ash borer (EAB) was confirmed in Chisago County by the Washington County border near Manning Trail. Two adults were discovered on a purple EAB trap. When a follow up visit was conducted, an ash tree with tunneling consistent with EAB was found adjacent to the trap.

The specimens were sent to the USDA for confirmation (standard procedure when EAB is found in a county for the first time). Assuming the beetles are verified as EAB, Chisago County is likely to be put under quarantine sometime next week. A quarantine helps prevent EAB from spreading outside of a known infested area. It is designed to limit the movement of any items, including ash trees and ash tree limbs, as well as all hardwood firewood, to help reduce the spread of EAB

Chisago County becomes the ninth county in Minnesota to confirm EAB, joining Anoka, Dakota, Fillmore, Hennepin, Olmstead, Ramsey, and Winona counties. For more information about EAB, see Emerald ash borer in Minnesota. See also the MDA news release, MDA identifies emerald ash borer find in Chisago County.
A purple trap discovered EAB for the first time in Chisago
County.  Photo: Jeff Hahn, UMN Extension

Monday, August 3, 2015

Seeding your lawn this fall? Here are some considerations (Part 2 of 2)

Previously I wrote about the different renovation options for fall seeding of lawns and about the various attributes of cool-season lawn grasses.  This week I wanted to discuss the mixtures and blends of grass seed that are on the consumer marketplace.  If you’ve ever walked into your local big box store or garden center looking for grass seed, the different products available can be fairly intimidating.  To be honest, I often have a difficult time finding the right mixture, because it only takes one bad ingredient to produce a poor quality lawn.  With that in mind, let’s take a look at several categories of grass seed mixtures that are available to you.
Midwest Mixtures, Northern Blends, Sun and Shade Mixtures
Many companies sell seed mixtures under these names.  Generally, these mixtures will contain a large percentage of Kentucky bluegrass, with perennial ryegrass and strong creeping red fescue included.  For existing average quality lawns this is a good mixture of species, and chances are your lawn already has some of these species established.  Perennial ryegrass will be the first species to germinate, generally 3-5 days after planting, and the other species will fill in over a 10-30 day period.  Bluegrass and ryegrass do not perform well in the shade, so creeping red fescue is a great addition to this mix for its shade tolerance.  Below are three examples of these mixtures.
Northern blend
Northern Blend (Performance Seed) seeded July, 2014. Picture taken July, 2015. Seed mixture includes: ‘Blue Angel’ Kentucky bluegrass (9.71%), ‘Kenblue’ Kentucky bluegrass (9.64%), ‘Ginger’ Kentucky bluegrass (9.51%), ‘Stallion’ perennial ryegrass (33.68%), ‘Boreal’ strong creeping red fescue (23.87%), and ‘Gulf’ annual ryegrass (9.69%). Cost = $2.39/lb of seed.
Midwest mixture
Midwest Mix (The Scotts Company) seeded July, 2014. Picture taken July, 2015. Seed mixture includes: ‘Jump Start’ Kentucky bluegrass (9.48%), ‘Right’ Kentucky bluegrass (7.71%), ‘Midnight II” Kentucky bluegrass (3.0%), ‘Wendy Jean’ strong creeping red fescue (8.5%), ‘Treazure II’ Chewing’s fescue (4.87%), ‘Silver Dollar’ perennial ryegrass (7.55%), and ‘Defender’ perennial ryegrass (6.83%). Also includes 50% Super Absorbent Coating. Cost = $10.39/lb of seed.
Sun and Shade
Sun and Shade (Barenburg) seeded July, 2014. Picture taken July, 2015. Seed mixture includes: ‘Baron’ Kentucky bluegrass (13.8%), ‘Barderby’ Kentucky bluegrass (4.59%), ‘Bargita’ perennial ryegrass (19.85%), ‘Barlennium’ perennial ryegrass (14.52%), ‘Tam 90′ annual ryegrass (14.74%), ‘Frazer’ Chewing’s fescue (9.73%), ‘Predator’ hard fescue (7.46%), and ‘Contender’ strong creeping red fescue. Also includes 7.5% Water Saver Seed Coating. Cost = $3.72/lb of seed.
The mixtures above would be consider standard lawn mixtures for Minnesota.  You will notice that two of the mixtures have annual ryegrass included.  Ideally I suggest to choose mixtures without annual ryegrass because it will compete with other grasses during establishment and it will not persist for longer than one year.  However, the inclusion of a small percentage of annual ryegrass in a seed mixture will not cause long lasting issues in lawns.
Dense Shade Mixtures
In a perfect world there would be consistency among species that are included in shade grass mixtures, but this is not the case.  Many companies will label mixtures as shade tolerant, but the species included do not reflect our knowledge of which grasses are better adapted for the shade.  There are no criteria for what can and can’t be labeled as a shade mixture, so this is very much a buyer beware situation.  Below are three examples of shade or dense shade mixtures.
Dense shade
Dense Shade (Pennington Seed) seeded July, 2014. Picture taken July, 2015. Seed mixture includes: ‘Rebel Xtreme’ tall fescue (37.0%), ‘Penn RK4′ tall fescue (37.0%), ‘Razor’ strong creeping red fescue (12.0%), ‘Survivor’ Chewing’s fescue (12.0%). Cost = $5.55/lb of seed.
Shade grass
Shade Grass (Performance Seed) seeded July, 2014. Picture taken July, 2015. Seed mixture includes: V.N.S annual ryegrass (47.82%), V.N.S perennial ryegrass (28.68%), V.N.S creeping red fescue (19.25%). V.N.S means variety not stated. Cost = $2.42/lb of seed.
ultra dense shade
Ultra Dense Shade Mix (JRK Seed) seeded July, 2014. Picture taken July, 2015. Seed mixture includes: ‘Epic’ strong creeping red fescue (19.68%), ‘Boreal’ strong creeping red fescue (19.57%), ‘Culumbra II’ Chewing’s fescue (19.53%), ‘Reliant IV’ hard fescue (9.82%), ‘Laser’ poa trivialis (19.85%), ‘Double Time’ perennial ryegrass (9.84%). Cost = $8.12/lb of seed.
The Dense Shade mixture from Pennington Seed includes tall fescues (coarse type) and fine fescues; these species are well adapted to shaded environments and ultimately this mixture should have good performance.  Keep in mind that tall fescue is a coarse textured bunch-type grass and it can be unsightly when seeded into existing fine textured grasses, but if you’re looking for nice green color and healthy grass in the shade, this mixture will meet your needs.  The Shade Grass mixture from Performance Seed has almost 50% annual ryegrass and 30% perennial ryegrass, which are not shade tolerant grasses.  Finally, the Ultra Dense Shade Mix from JRK Seed has four different fine fescues, which are shade adapted, and almost 20%Poa trivialis (rough bluegrass) and 10% perennial ryegrass. This mixture will grow well in the shade, but in full sun situations the Poa trivialis will become stressed and brown out in the summer (as seen in the picture).  I often caution homeowners about using mixtures with Poa trivialis because it can escape and establish into full sun areas, eventually forming distinct patches that resemble disease.  This mixture should only be used in dense shaded situations where other grasses will not grow.
Quick Repair Mixtures
Sound too good to be true?  Generally it is.  Quick repair mixtures include large percentages of annual ryegrass, which does not persist in lawns for longer than one year.  I suggest to avoid using these mixtures.  Below is an example of this type of mixture.
easy green
Easy Green (Performance Seed) seeded July, 2014. Picture taken July, 2015. Seed mixture includes: V.N.S annual ryegrass (92.5%) and V.N.S perennial ryegrass (4.0%). Cost = $1.44/lb of seed.
Specialty Mixtures
If you look hard enough, you’ll notice newer mixtures of grass seed emerging on the marketplace.  Two of my favorite products in this category include blends of tall fescue and mixtures of fine fescues.  Blends of tall fescue generally include 3-4 varieties, and these blends are great for new establishments of low maintenance areas, high traffic and shaded environments.  Mixtures of fine fescues are often called “low growing” or “no mow” mixtures.  These mixtures are great for low maintenance situations where less mowing is desired.  The fine fescues will blend in well with existing grass species and are adapted to the shade.  Don’t let the name of the mixture fool you, these grasses can also be mowed at standard lawn heights.
High traffic mixtures often include a large percentage of perennial ryegrass, which will tolerate traffic much better than other species.  However, perennial ryegrass can suffer significant winter injury in Minnesota, so keep that in mind when using these mixtures.
Grass repair kits, which are used for overseeding bare patches in lawns, often include similar species as the Midwest Mixtures or Northern Blends.  Most of these kits include 10-20% seed and 80-90% paper mulch.  The mulch can aid in establishment by holding moisture and preventing the seed from drying out, but keep in mind that you are only paying for a small amount of seed.  In turn, the seed cost per pound can be rather expensive.  The Dog Patch kit from Amturf costs $40.38/lb of seed and the Grass Repair Kit from Encap, LLC costs $12.22/lb of seed.
Magic Grass
We’ve all seen the advertisements for “the best grass seed ever” and “plant it and forget it” mixtures.  Much like the dense shade mixtures, these are buyer beware situations.  Here is some of the language you might see on the bag of seed:
– “up to 4x deeper rooting”
– “no more watering, fertilizing, or pest control”
– “dwarf height requires minimal mowing”
Some examples of these mixtures include Bob Villa’s Grassology and Cutting Edge Grass Seed.  What do many of these mixtures have in common?  After reviewing of these products I’ve come to find many similarities: 1) Most of them have at least five species, generally more.  Companies do this to be sure they have something that will grow anywhere, but the result is often less than satisfactory.  Also, while diversity is good, you don’t know what you’re getting because varieties are often not stated.  2) It can be difficult to find the seed label and the species included.  3) Many have 50%+ inert matter or seed coating, which reduces the cost to the manufacturer and transfers it to you.  4) These can be some of the most expensive seed mixtures. 5) Claims are rarely backed by any science and/or data.
Final Thoughts
Purchasing high quality grass seed is one of the most important considerations when overseeding, renovating, or establishing new lawns.  This two-part article should help to give you more direction when you venture to the store and gaze at the seemingly endless isles of lawn seed.  If you are unsure of whether a particular mixture is right for you, be sure to ask someone or do some investigation.  For more information on purchasing and planting grass seed, have a look at these resources:

Friday, July 24, 2015

Seeding your lawn this fall? Here are some considerations (Part 1 of 2)

Lawns in Minnesota take a beating. This is no surprise due to the extreme weather swings that we have from season to season and even within seasons. Fortunately this year has been a banner year for lawn care with plenty of rain, mild temperatures and low dew points. However, the current ten day forecast is setting us up to have some of the highest temperatures we’ve seen this summer, with dew points in the 70's. We may have another month of hot weather and then it will be time to seed bare areas in your lawn or conduct lawn renovations. With that, now is the time to start thinking about seed selection and purchasing.

Depending on the condition of your lawn and your goals going forward, I may recommend one of several renovation options and seed mixtures. Ideally, this work would be carried out from mid-August to mid-September. Renovation strategies can be grouped into four categories:

Lawn improvement- conducted when less than 20% weeds or bare soil are present. The goal is to utilize existing grass species and determine the factors leading to poor lawn quality and correct these. Often, recommended practices for improvement will include aeration, fertility, seeding, and weed control.

Partial renovation- conducted when 20-40% weeds or bare soil are present. This process requires stressing the existing vegetation to reduce the competitive advantage of existing species, while overseeding with new (possibly different) turf species. Depending on the weeds present, herbicides may or may not be recommended. 

Species conversion- conducted when greater than 40% weeds or bare soil are present, but there are no major soil issues. This process requires killing the existing vegetation by the use of non-selective herbicides or solarization (plastic sheet) and overseeding with new turf species. The species conversion process allows you to change the function of the lawn (ex: low input, no mow, high traffic tolerance) by establishing new species in a short period of time. 

Complete renovation- conducted when greater than 40% weeds or bare soil are present, and soil remediation is required. This process is essentially the same as the species conversion except soils will be tilled, graded, and possibly amended with organic matter or nutrients.

For more detailed information about all of these renovation strategies and in-depth detail on how to conduct the species conversion, view this webinar: Lawn Renovation

No matter which renovation strategy you choose, selection of the proper seed will be critical to the long term success of your lawn. I would generally suggest utilizing a mixture of several turfgrass species to overseed with, but let’s discuss the species individually and next week we’ll look at some mixtures that are available to you.

Mixtures vs. Blends


Mixtures are different from blends. Blends of grass seed include only one species, for example Kentucky bluegrass, and most blends would have 3-4 different varieties of that species. Mixtures of grass seed include two or more species and greater genetic diversity. Mixtures are often utilized for lawns that have differing microclimates (ex: sun and shade).

Cool Season Species for Minnesota Lawns


Leaf texture differences between tall fescue (left), Kentucky bluegrass (center),
and fine fescue (right)


Kentucky bluegrass is the most widely used species in Minnesota lawns due to its high aesthetic quality, adaptation and stress tolerance. If you have an existing lawn, chances are that a good majority of it is Kentucky bluegrass. Additional benefits of Kentucky bluegrass include its cold tolerance, drought survival through dormancy and high recuperative ability. However, downfalls with this species include a high water requirement, frequent mowing and high fertility needs. There is a wide range of genetic diversity in Kentucky bluegrass and Seed Research of Oregon has put together this great classification of the different varieties: Kentucky Bluegrass Classification.

Perennial ryegrass can also be a high quality species, although its poor tolerance to winter and summer stresses make it undesirable in many cases. Perennial ryegrass is included in many of our Midwest mixtures due to its incredible germination and establishment rate. If quick establishment is desired, perennial ryegrass can be used, but I would suggest not using more than 25% perennial ryegrass in your seeding mixture.

Fine fescues have been receiving a lot of attention recently because of their ability to survive low maintenance environments. Fine fescue is a category of about five different species that are often mixed together. These species include hard fescue, slender and strong creeping red fescue, Chewings fescue, and sheep fescue. Like perennial ryegrass, the fine fescues germinate very quickly. Fine fescues are often the best performing species in drought trials and no-mow turf situations. They are also adapted to shade or full sun. For more information on fine fescues for lawns have a look at this short video: Fine fescue.

Tall fescue is a coarse fescue species that has been gaining popularity due to its shade and traffic tolerance, as well as its ability to avoid drought through an extensive root system. I find myself recommending tall fescue more and more. Tall fescue is a bunch type grass and it can be unsightly when overseeded into existing lawns, so I generally recommend using it for new seedings or utility turf areas. When tall fescue is greater than 75% of a stand it looks very comparable to a Kentucky bluegrass lawn, and it will require less inputs of water and fertilizer. Tall fescue is also very shade adapted. For more information on tall fescue have a look at this short video: Tall fescue.

For a more detailed explanation of the turf species visit this short video: Grasses for Minnesota Lawns.

Next week we will look at the various seed mixtures that are available on the consumer marketplace. Stay tuned.
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