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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.

Friday, July 17, 2015

Tiger swallowtail caterpillars

Jeffrey Hahn, Extension Entomologist

People have been finding tiger swallowtail caterpillars in the landscape recently. They have been on the move as they look for places to pupate. Upon first sight, this insect is quite mysterious looking. It is up to a little over two inches in length. The body is either brownish or greenish with a yellow stripe circling the body somewhat near the head.

What stands out, however, are two large yellow and blue eyespots in front of the yellow stripe. This gives the
Tiger swallowtail caterpillar. Note the
orange osmeterium near the head and
the yellow and blue eyespots.  Photo:
Howard Ensign Evans, CSU State Univ.
caterpillar a rather menacing appearance. To further enhance this threatening look, the caterpillar can swing its head from side to side, mimicking a snake. And if that was not enough to keep someone at bay, it can evert a forked structure called an osmeterium near the head. This structure can not only startle someone but can also emit a foul odor to help protect the caterpillar.

Despite all of its bluster, a tiger swallowtail caterpillar is perfectly harmless to people. Don’t be alarmed if you see one, just let it go on its way and know it will grow to be a beautiful tiger swallowtail butterfly.

To see more pictures, see the eastern tiger swallowtail entry in BugGuide

Cedar Apple, Quince and Hawthorn Rust

M. Grabowski, UMN Extension Educator

Cedar apple rust on Zestar apple, M Grabowski UMN Extension
Several rust fungi are now showing up in brilliant colors on hawthorn, apple, crabapple and other trees and shrubs in the Rosaceae family. Infected leaves have bright orange, yellow or red spots. Infected fruit are covered with small tube like fungal structures, that pour out large quantities of powdery orange fungal spores. Cedar apple rust, hawthorn rust and quince rust are all caused by fungi in the genus Gymnosporangium. The Gymnosporangium rust fungi infect juniper for half of their life cycle. On cool wet spring days gelatinous bright orange spores can be found on galls or cankers on juniper trees. Those spores cause the infections on trees and shrubs in the Rosaceae family. In turn spores produced by the Rosaceae trees and shrubs will infect junipers.

Quince Rust on Hawthorn Fruit, M. Grabowski UMN Extension
As a result of this unique life cycle, leaf spots may grow slightly bigger, but no new leaf spots or fruit infections will form this year on the Rosaceae trees and shrubs. The Gymnosporangium rust fungi rarely cause damage to the health of  trees and shrubs in Minnesota. So enjoy the colors and unique biology of these interesting fungi. No management is needed.

Garlic Rust

M. Grabowski, UMN Extension Educator

Orange and black elliptical spots on garlic leaves and stems are signs of garlic rust. Cause by the fungus Puccinia allii, garlic rust can infect several members of the allium family including garlic, onion, chives and leeks. Severe infection can result in yellow, withered leaves and reduced bulb size. Not much is known about the biology of the garlic rust fungus. Infection occurs in cool moist conditions and two different types of spores are commonly found on infected plants. The orange spots produce urediniospores. These are easily spread from plant to plant during the growing season resulting in new leaf spots. The black spots produce teliospores. These tough spores survive in plant debris and start new infections the following growing season.

If garlic rust appears in the garden, remove all leaf and stem debris from the garden after harvest. These infected leaves and stems can be burned, buried in an area where no alliums will be grown or composted in a pile that heats up. If backyard composting is not available many areas offer municipal compost drop off sites. Avoid planting garlic, onions, leeks or chives in the same area for the next 2-3 years. It is not known if the garlic rust fungus can move from an infected plant into the garlic cloves used for seed, but disease originating from infected seed has never been reported.

Japanese beetle management options

Jeffrey Hahn, Extension Entomologist

Japanese beetles are being found in gardens and yards now. Although the first discovery of these pests was recorded on June, 18, it hasn’t been until more recently that they have become more abundant. Japanese beetles are challenging to deal with, especially when they are numerous. The following are non-chemical and chemical options for managing them.
Japanese beetles having their way with a grape leave.
Photo: Jeffrey Hahn, UMN Extension

A good non-chemical method is physical removal. To be effective, it should be done every day (or at least as regularly as possible). If you can only handpick these pests once a day, research shows the best time to do so is during early evening. Have a container of soapy water with you so that beetles that are brushed or picked off the plants end up in the water where they are killed.

For smaller plants, consider using a fabric barrier, like cheesecloth. The fabric is placed around the plants, preventing the Japanese beetles from getting at them. You can make your own or buy them from a garden store or online site that sells garden supplies (e.g. Gardens Alive). The fabric should be lightweight and allows light and rain in. Be sure to take the fabric off of any plants that are flowering so bees can reach them.

One non-chemical method to avoid is traps. Although they are popular and can capture an impressive number of beetles, what are found in the traps is actually just a small number compared to how many Japanese beetles are actually out there. Research from the University of Kentucky has shown that these traps actually attract more Japanese beetles than they capture; plants in these areas often suffer more damage than they would have without the traps.

If you are interested in using an insecticide, consider a low impact product like Neem. Neem does actually kill them but causes them to stop feeding. While this can be effective on small to medium numbers of beetles, it is less effective against large numbers. Another option is pyrethrins (containing piperonyl butoxide). Pyrethrins do not contain any residual; it is only effective on what it directly contacts and repeat applications are likely necessary.

If you would like to use a product with a longer residual, consider a pyrethroid, such as permethrin, bifenthrin, lambda cyhalothrin, or cyfluthrin. Another option is carbaryl (Sevin). Depending on the Japanese
Japanese beetles on basil.  Be sure to check to insecticide
the label to be sure the plants you wish to treat are listed.
Photo: Michelle Grabowski, UMN Extension
beetle numbers, you may need to make more than one application. Be careful not to apply one of these insecticides when bees are active.

Another option is the use of imidacloprid, a type of systemic insecticide (dinotefuran is a similar systemic insecticide but is less effective against Japanese beetles). It’s easy to apply and is long lasting so only one application during the summer is necessary. It does not kill Japanese beetles quickly but it does cause them to stop feeding, then they die a little later. It is important to note that this product is very toxic to bees. Avoid treating flowering plants (or plants that may still flower later this summer) that are attractive to bees.

When applying insecticides, be sure that the plant you wish to treat is listed on the insecticide label. This is especially important when treating fruits and vegetables. If the plant you wish to treat is not on the label, then do not make an application to it. Instead, find a product that is cleared for the plants you are trying to protect.

Friday, July 10, 2015

Mints - friend or foe?

Mint plant
Rhizomatous roots and creeping stems

Mints have square stems.
 Plants in the Mint family have a well-know reputation for being aggressive. Some, like creepingCharlie Glechoma hederacea) are common pests for many homeowners and gardeners. Wild mint (Mentha arvensis) is a Minnesota wildflower.

Mints can most easily be identified by their square stem and fragrant leaves when crushed. Mints are aggressive and have rhizomatous root systems and creeping above-ground stems, making them difficult to eradicate. Mints grow well in sun and shade, and are adaptable to various soils. Many mints are grown for culinary use, and mints - including creeping Charlie - are good sources of nectar for pollinators.Still, some people want to eliminate large areas of wild mint (and creeping Charlie) from their landscape. There are essentially three options: (1) treating the area with a broadleaf herbicide with glyphosate + triclopyr. (2) Solarization using clear plastic sheeting. (3) Dig out the plants, removing as much of the plant root as possible.

(1) Spraying a broadleaf herbicide would be the fastest option. However, the broadleaf herbicides noted above are non-selective and will most likely kill every plant. So it is important to treat the area on a calm day (no wind) and to protect desirable plants with mechanical barriers such as cardboard pieces / boxes, leaf bags, tarps, etc. These should be left in place till the sprayed foliage is dry. Always follow the instructions for proper chemical use, storage and disposal on the product label.

(2) Option two is solarization. Plants are cut back and sheets of clear plastic (not black) are laid down tightly over the plants. Solar energy will heat up and kill the plants and seeds. The plastic should stay in place until plants have died back completely. According to the University of California IPM website, this may take 4-6 weeks depending on the intensity of the sun's energy, number of sunny days, and the plants' resiliency.
(3) Option three- and most labor intensive - is digging out the mint. Because mint can vegetatively propagate - grow from a small piece of root or stem - it is important to dig out as much of the root as possible and resist pulling the plants out thus breaking the roots. Digging out the plants could be done in conjunction with Option one or two as well.

After eradicating the mint, it is important to follow up regular weeding and treatment as necessary. If re-establishing lawn, choose grass seed appropriate for the site and re-seed as per Lawn Renovation. For landscape beds, mulch the area with 2-3" of wood mulch and / or replant with preferable plants. See Extension publication Mulching the Home Landscape. Typically, landscape fabric is not recommended nor is it necessary; however, because the goal is to prevent a perennial from re-sprouting, fabric is an option under the wood mulch.
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