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A newsletter by the Renville County Master

Gardeners containing USDA Zone 4 appropriate

information Volume 141 September 2020

Meet the Renville County Master Gardeners

Louise Schweiss

Anderson–Fairfax; Joy Clobes - Fairfax

Teide Erickson - Winthrop Sandy Feldman –

Renville,

Cathi Fesenmaier –

Olivia; Erin Grams – Hector;

Susan Haubrich –

Danube;

Betsy Hennen –

Olivia; Jan Howell – Olivia;

Pam McColley -

Franklin;

Linda McGraw –

Buffalo Lake;

Beth O'Keefe – Morton;

Marie O'Keefe –

Morton

Barbara Stone-

Renville

The University of Minnesota is committed to the policy that all

persons shall have equal access to its programs, facilities, and employment without regard to race, color, creed, religion,

national origin, sex, age, marital status, disability, public assistance status, veteran status, or sexual orientation

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Extension Master Gardeners - Renville County

Inside this Issue:

September Garden Tips – Page 2

Love My Pets but Love My Landscape - Page 2

Lilac Foliar Diseases on the Rise – Page 3

Sowing Grass Seed -Page 4

Another Invasive Insect Confirmed in Minnesota –

Page 5

Nature Heals Webinar-Page-5

Cover Crops Improve Soil Health, even on small

scale – Page 6

Divide Peonies and Irises Now! – Page 8

What’s Happening – Page 9

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It is only the farmer who faithfully plants seeds in the Spring, who reaps a harvest in the Autumn.” B.C. Forbes

This Photo by Unknown Author is

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September Garden Tips

• Interested in becoming an Extension Master Gardener? For more

information go to z.umn.edu/GrowWithUs.

• Keep adding perennials to your garden and landscape. The warm

soil and cooler air temperatures are great for planting and

establishing new perennials.

• Take cuttings of oregano, rosemary, sage, marjoram, mint, and winter savory for your indoor winter

herb garden. Take 3- to 4-inch cuttings from healthy plants. Stick the cut end in moist vermiculite or

perlite. Keep the vermiculite moist and the plant in a bright, but not sunny, location. Plant the rooted

cutting in a small container of moist, sterile potting mix.

• Dig up your tender bulbs and tubers well before the threat of frost. Cure (put in a warm, dry place out

of direct light) and store.

• Plant garlic for next season between now and November 1. Plant the cloves in an upright position, 3 to

5 inches apart and 1 inch deep. Protect the young plants with winter mulch.

• Houseplants that have spent the summer outside should be cleaned up before going inside. Check plants for insects, webbing, eggs, etc. and remove or treat. Wipe off pots and wash saucers. Remove plant debris from soil surface. Re-pot plants with fresh, sterile potting soil to avoid bringing critters into your home.

Source: “Month-By-Month Gardening Minnesota & Wisconsin” by Melinda Myers

Love My Pets but Love My Landscape By

Louise Schweiss Anderson, Renville County Master Gardener

I stopped by a neighbor’s home recently and discovered the greatest landscape hack I have seen in a long time. Their two dogs love to lie in the cool soil of their landscape plants or cushion themselves by simply lying on top of the plant material. Creative people that they are, what I saw were simple rod stakes in varying heights with a flat washer attached to the top to prevent the animals from lying down on top of or in the plant The washer prevents the pet from impaling themselves. Paint them green and they disappear within the plant. Problem solved.

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Lilac Foliar Diseases on The Rise By Dr. Lina Rodriguez Salamanca, Plant and Insect Diagnostic Clinic iastate.edu Leaves showing evidence of powdery mildew

In the last month we have received many inquiries regarding lilacs. On the few leaf samples, we have received, we have observed mainly three different fungal pathogens: Pseudocercospora and Septoria causing leaf spots, and powdery mildew. All are contributing to leaf blight (rapid death), and some cases to abundant leaf drop.

This year environmental conditions and dew has proven very conducive for the pathogen. Also, stressors like drought could be exacerbating these problems. When assessing your lilacs, it is also good to examine the stems and trunk for evidence of any mechanical injury that may be caused by borers: https://hortnews.extension.iastate.edu/lilacash-borer, animals, or mowing equipment.

This is a good reminder that good care and pruning can help improving airflow on shrubs and tree health in general. Pruning Ornamental Shrubs is a resource to help with that. Removing and destroying leaf debris and pruning out dead branches may be the

best and easiest strategy in reducing diseases in general for shrubs and trees. Leaf spot caused by fungi (Pseudocercospora and Septoria)

Leaf spots expand and cause blight

Fungal leaf spots rarely become severe enough to cause the decline of the plant. However, if repeated severe infections occur, fungicide treatments should not be considered, as it is too late into the summer. Preventative spring to early summer fungicide applications may help prevent

diseases (but will not eradicate them). All care you can provide, so plants thrive can help. You may consider renovating your established lilacs. see the article renovating lilacs. See our articles on lilac diseases: https://hortnews.extension.iastate.edu/lilac-pseudocercospora-leaf-spot https://hortnews.extension.iastate.edu/powdery-mildew Other lilacs problems but not as common

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Lilacs perform well in clay soils, but slow water drainage leads to excess moisture in the root zone, and prone to root rots, with less defined foliar symptoms (no spots nor mildew on top). See https://hortnews.extension.iastate.edu/2017/01/phytophthora-shoot-blight-lilacs Lilacs are also susceptible to verticillium wilt, where the leaves will look droopy, and water-deprived, change from green to yellow to brown and drop. See the article Verticillium Wilt. -https://hortnews.extension.iastate.edu/verticillium-wilt

Yard and Garden: Sowing Grass Seed Fall is an ideal time to sow grass seed in Minnesota By: Richard Jauron

Sowing grass seed at the optimal time of year, selection of a high-quality seed mix appropriate for the site and consistent watering are keys to successfully establishing grass from seed. In this week's Yard and Garden article, Richard Jauron, horticulture specialist with Iowa State University Extension and Outreach, offers some insight.

When is the best time to sow grass seed?

Mid-August to mid-September is the best time to seed new lawns and overseed existing lawns in Iowa. Late summer seeding has several advantages over spring seeding. The seeds of cool-season grasses germinate quickly in the warm soil of late summer. The warm days and cool nights of early fall promote rapid turfgrass growth. The growing grass also has less competition from weeds, as few weed seeds germinate in fall. Grass seed can also be sown in spring (April to mid-May) in Iowa. However, spring seeding is often less successful than late-summer seeding.

What should I look for when buying grass seed? When purchasing grass seed, choose a high-quality seed mix that is best adapted to the site. In sunny areas, Kentucky bluegrass is the best choice. Select a seed mix that contains at least two or three bluegrass cultivars. Perennial ryegrass is often included in many bluegrass seed mixes because of its ability to germinate and establish quickly. Use a mixture containing Kentucky bluegrass, perennial ryegrass and fine-leaf fescues in areas that contain sun and shade. The fine-leaf fescues (creeping red fescue, hard fescue, chewings fescue, etc.) are the best grasses for shady locations.

How often should I water a newly seeded area? After seeding, keep the upper 1 inch of soil moist with frequent, light applications of water. Two light applications of water per day are usually sufficient. However, it may be necessary to water three or four times on windy, sunny days. The seeds of most turfgrasses should germinate in two to three weeks if the seedbed is kept uniformly moist. Gradually reduce the frequency of watering, but water more deeply, when the grass seedlings reach a height of 1 to 2 inches. Photo credit: Seeding grass by Elenthewise/stock.adobe.com

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Another invasive insect confirmed in Minnesota By: Jeffrey Hahn, Extension entomologist

The Minnesota Department of Agriculture (MDA) has confirmed that European chafer (Amphimallon majale) has been found for the first time in the state . This invasive insect is a severe pest of turfgrass. First found in the U.S. in New York in 1940, European chafer is now found in 10 states including parts of Wisconsin and Michigan. The first European chafers in Minnesota were found in south Minneapolis earlier this summer.

• European chafer is about ½ inch long and is tannish to reddish

brown. • It resembles a May/June beetle, although May/June beetles are

usually a little larger and darker in color. • Adult European chafers typically emerge from the soil in early

summer at dusk on warm, clear nights. • They swarm around small trees and shrubs to mate for several

hours before returning to the ground. It is easy to miss their activity.

While the adults are not pests, the larvae (grubs) are considered more destructive to turf than Japanese beetles because they feed longer during the year.

• The grubs have a reddish yellow head with conspicuous legs and a body bent into a C -shape. • They range in size from ¼ inch to almost one inch. • They look very similar to Japanese beetle and May/June beetle white grubs and can only be

distinguished by close examination of the tip of their abdomen.

The MDA wants to better understand where European chafers are in Minnesota. Minnesotans can report suspected European chafers to the MDA’s Arrest the Pest line at arrest.the.pest@state.mn.us or 1-888-545-6684. Before making a report, capture the insect, take a picture, and put the insect in a container or plastic bag and save it in the freezer. The MDA will contact you if they need the specimen for confirmation.

For more information, see MDA’s European chafer page.

Nature Heals Webinar

If you've ever experienced a sense of calm by looking at nature, you've experienced nature-based therapeutics in action. Learn more from the

-Based Therapeutics-An Intro to Nature --Webinar: Nature Heals

ttps://www.youtube.com/watch?v=3a46Bk7vdiI&feature=share&app=desktophat the Based Therapeutic Services Program-Natureled by Jean Larson, manager of the

Arboretum. The recorded webinar introduces the rationale, evidence and benefits of nature-based therapeutics, and explains the critical role of nature in self-care,

community-building and planetary health.

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Cover crops improve soil health, even on a small scale BY: Natalie Hoidal, Extension educator, local foods, and vegetable production

Have you ever felt like you want to invest in soil health, but it’s hard to know how to apply soil health concepts on a small scale? Cover crops are an important tool to improve the health of your soil. While much of the literature and resources available to help growers navigate cover crops are aimed at larger farms, you can use cover crops at any scale.

Why use a cover crop? Live roots maintain soil structure and provide a diversity of benefits. A core tenant of soil health is keeping living roots in the soil. Living roots help maintain nutrients in the upper soil horizon, they support a diversity of soil microorganisms, and they can help the soil retain water. Additional benefits of cover crops include building soil organic matter when they are broken down and reincorporated into the soil and, depending on the species, they can provide pollinator habitat and fix nitrogen.

When should I plant? In Minnesota, we typically only grow crops for a couple of months, leaving the soil bare the rest of the time. Any time you do not have a primary crop growing, you can grow a cover crop. Common windows include before planting your main crop, in between crops, and after you have harvested. Here are three example scenarios:

1. When planting tomatoes or pumpkins, many gardeners do not transplant or seed until mid-June. In this scenario, you could plant a cool season cover crop in early May and work it into the soil in June before planting your main crop.

2. If you use a bed to grow an early-season crop like lettuce, you might harvest in May or June and then wait to plant that bed again until later in the summer. You could grow a fast-growing cover crop in the window between plantings.

3. Some crops like cucumber and zucchini get pulled around early August, leaving the soil bare for the remainder of the season. In this scenario, you would plant your cover crop after harvesting your main crop, and either allow it to die over the winter (by choosing a non-hardy species), or cut it and work it into your soil the following spring.

You can grow a cover crop during the main season in areas that are not being used. A common example is planting clover between rows instead of mulching.

What species should I choose? There are three main things to think about when choosing a cover crop for your space: Some cover crops provide additional ecosystem services. Crimson clover is an excellent food source for pollinators.

Will it die over the winter? Most cover crops will naturally die over the winter (examples include buckwheat, oats and peas, phacelia, Sudangrass, tillage radish). Others, like winter rye, survive the winter and need to be terminated, or killed

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and worked into the soil. In a small garden, I suggest a species that will die over the winter, simply because it’s easier to manage.

Farmers who use cover crops that overwinter have flail mowers and other equipment for termination; you could do this with a machete or a very tough lawnmower, bu t if you’re trying a cover crop for the first time, a winter-killed species will be easier.

What benefits are you looking for? Do you want your cover crop to fix nitrogen? If so, make sure to choose a legume like peas, vetch, clover, or beans.

Do you want it to provide food for pollinators? If so, choose a flowering crop like buckwheat, phacelia or clover, and make sure to read the seed label in order to plant it with enough time for it to flower before the first freeze.

When are you planting? Depending on when you plant your cover crop, you may have limited options. The Midwest Cover Crop Council has an excellent decision-making tool with a long list of cover crops and planting windows for your county.

Say you wait until September to plant a cover crop; the tool will tell you which species can be reliably planted in September in your area, leaving enough time for good establishment before the first freeze. Other cover crops do not do well in the summer heat; the tool will tell you which cover crops can reliably establish in August, and which cannot.

How do I plant a cover crop? Many garden stores sell cover crop seed, as do vegetable seed catalogs. The seed company shou ld tell you the recommended amount of seed for your area. Most cover crops should be planted fairly densely, more like a crop field than a vegetable garden.

Depending on your scale, you may be able to seed by hand. One simple trick that mid -size growers use is drilling seed-sized holes in a 5-gallon bucket, filling the bucket with seed, and walking up and down the field shaking the bucket for even seeding. For best results, start with a weed-free seedbed and make sure to fertilize your cover crop like you would a regular crop.

One of the goals when using a cover crop is to establish as much biomass as possible, which you can then work back into your soil as organic matter. If a crop is adequately fertilized, it will be more likely to produce a healthy amount of biomass.

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Divide peonies and iris NOW! BY: Mary H. Meyer, Extension horticulturist

Peonies and iris are long-lived favorite perennials for Minnesota. Peonies can easily outlive their gardeners and may not need to be divided or moved. Iris, especially bearded iris, benefit from regular division and flower better when they are regularly divided. August is a good time to divide these perennials.

Iris Iris borer caterpillar Iris tend to go dormant and slow their growth, so it is good to divide them when the plant is not actively growing.

Any yellow foliage can be inspected for the dreaded iris borer, which by August has moved down the foliage and into the rhizome. Discard all rhizomes with borer damage, or if minimal, you may be able to save them, just be sure you have killed the borers.

• Cut the foliage back to 6-8 inches and keep one or two “flags” or foliage clus ters per rhizome. • Bearded iris prefers well drained soil, they rarely grow well in wet soils and can decay in standing

water. Full sun produces the best blooms on iris. • This should be done as soon as possible around Labor Day/ early fall.

Peonies

Peonies do not need division to continue to grow and flower, however, I am often asked about when to divide them because someone is moving, or they want to give a plant to a friend. Fall is the opposite season for flowers on peony and iris, so that is the perfect time to divide these two perennials.

If you have dug a peony, you know it’s got a big fleshy root system that provides lots of stored food to keep the plant growing for many years. But trying to get all of the root can be a challenge. Older peonies

have large roots.

Peony flower buds have a cold or chilling requirement before they actually flower, so they grow well in cold climates. Peony flower buds are below ground and if too protected and deep, they may not

accumulate their chilling requirement and fail to flower.

Peony eyes or buds at the root-shoot junction should be planted 1.5 inches deep. Too shallow or too deep planting may inhibit flowering.

The other good thing about fall peony division is you can remove any diseased foliage, such as the black spots or botrytis blight that all peonies seem to get by September. Sanitation is a good prevention for botrytis, so cleaning up the peony foliage in fall is a

good idea.

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What’s Happening

In our area ; If you are interested in more information, contact a

Master Gardener or email the Renville County Extension

Office at mnext-renville@umn.edu

Need to contact us? Call the Renville County Extension Office at

320-523-3713, or e-mail us at mnext-renville@umn.edu

Monday – Thursday 8 a.m. to 4:30 p.m.

If you or you know someone who would love to join us as Master Gardeners, please contact the number above and one of our Master Gardeners will contact you. And NO, you do not have to be an expert already, none of us were or are at the present time. We just have places to go to get the information people need. So, if you just garden via pots, or have a small plot garden, or just love houseplants, you can become a Master Gardener. Because of all of us that belong have different interest and different knowledge levels. But we have one thing in common, we love plants. Anyone can do this; our group will help you the first year to get you what you need to get your official Master Gardener certificate. Application deadline is Octopber 1st. All you need to do now is Call US! Thank You! Renville County Master Gardeners

At the Minnesota Landscape Arboretum:

For more information on what’s happening at the For more information on what’s happening at the

Arboretum, please visit http://arboretum.umn.edu/gardeningclasses.aspx

MN Plants: Free Webinar Series

Live 7-8 p.m. Thursdays, May 14-Sept. 10

PlantMaker Studio - Online Learning at The Arb

This summer, the PlantMaker Studio moves online. Join Arboretum educator Reba Luiken as she

demonstrates family-friendly projects to do at home, wherever you live, with materials you already have

on hand. Each week a new project will help you learn a little more about plants and nearby nature and give you a chance to practice your creativity! https://sites.google.com/umn.edu/plantmaker-

studio-at-home