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We want to better understand who our readers are and how we can best meet your needs. Our first-ever reader survey will drive the future of Yard and Garden News, so it’s very important that you respond! We recognize your needs are unique and gardening is a diverse activity/hobby. In order to serve you better, we need information from you -- your opinions, your interests, and newsletter expectations.

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The survey will close on June 17. Thank you in advance for your much needed assistance!

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The gardening season in Northern Minnesota is brutal and harsh to say the least. Lack of heat units, freezing temperatures in early June and late August, very cool nights and high winds are very challenging to even the most experienced and patient gardeners. The long period of times that plants are wet from dew or prolonged rain can make disease control nearly impossible some years. Gardeners in Northern Minnesota are usually very optimistic people, continually telling themselves that next year things will be much better and the weather will be much more cooperative to help produce that lush, bountiful harvest that we all hope for. Then about every five years, somewhat ideal conditions come together and that super abundant crop is produced. And so the cycle goes.

High tunnels can help gardeners produce that great crop every year with little risk. High tunnels can lengthen the growing season as much as 5-6 weeks in the spring and also in the fall. What are high tunnels?

While high tunnels resemble greenhouses in appearance, this is the only similarity.  High tunnels do not use electricity, do not use artificial heat (except in emergency situations), use only a single layer of plastic, and achieve ventilation from natural airflow by rolling up the sides instead of using electric fans.  Drip irrigation is used to water the crops.

Crops in high tunnels are typically grown in the ground, as is the case for typical garden crops; however container gardening in high tunnels is very possible.

Compared to typical garden-grown crops the yield and quality of produce and flowers are usually far superior in high tunnels.  Additionally, Minnesota research has indicated that high tunnels have greatly aided in the control of diseases and in reducing common vegetable and flower pest problems.  High tunnels provide an excellent tool for organic production in Minnesota since diseases and other pests can be controlled without chemical intervention.

High tunnels can either be permanent or on heavy skids and movable. Some gardens use high tunnels to start early flower beds and pull the high tunnel away in early summer, allowing flowers to bloom several weeks earlier. Most vegetable gardeners prefer permanent structures as they are more weather resistant, especially in high winds.

While high tunnels can be constructed in many shapes and sizes, they must be of a minimum size to be effective and utilize solar radiation efficiently. While the jury is still out on an exact minimum size, I recommend at least 10-12 foot wide,6-8 ft high at the peak and about 20 ft long.

Before constructing a high tunnel, gardeners should raise the soil level at least 4-6 inches so the floor of the high tunnel is above the surrounding ground level. This will allow excess water from heavy rains to flow away from the tunnel.

While is it recommended to use a plastic that is six mil and UV treated greenhouse clear,  that will last four to six years, it is possible to start out with a inexpensive four mil clear plastic that will usually last only one year. However to get that very early spring start it is recommended to have that plastic already in place.  Therefore, it is recommended to leave the plastic on the entire year.

While high tunnels have many great advantages, gardeners must be aware that there is a learning curve to using high tunnels. Management concerns include: not letting the tunnels get too hot, supplying enough soil fertility, supplying timely irrigation through the drip tape and not letting the weeds get out of control.

High tunnel web sites that I recommend include www.hightunnels.org . This is a national site and has some simple designs using PVC and other materials. www.hightunnels.cfans.umn.edu  is the University of Minnesota High Tunnel Web Site and contains the online version of the Minnesota High Tunnel Manual, along with several recent powerpoint presentations and a list serve.  Gardeners interested in purchasing a hard copy of the Minnesota High Tunnel Production Manual may do so by calling 763-434-0400. The cost is 25.00 plus shipping.

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The popularity of creatively combining different plant materials in window boxes has soared in recent years. Combining plants of various color, texture, and plant habit to design what in essence become miniature landscapes provides gardening enjoyment from both outdoor and indoor vantage points.  Designing and having window boxes can become a very fun, creative, and rewarding endeavor. The diversity of plant materials to choose from and effects that can be generated seem almost limitless.  Many people choose to try different combinations and overall themes each year.  This makes it exciting for neighbors and passersby as they anticipate what will be next.

A decade ago when I was a greenhouse grower at an independent nursery, designing and raising our own combination planters was one thing that helped set us apart from the competition. Combining different species or cultivars of plants that grow in harmony with each other throughout both the production period and then as they matured after purchase is challenging and requires looking beyond just what looks good together at the time of planting. For instance, dark foliaged sweet potato vine looked fantastic in hanging baskets and window boxes with trailing verbena and bacopa at first.  However, as the season went along, the sweet potatoes being produced under the soil eventually crowded out the other plants if the containers were relatively small. Much of the fun is to experiment and discover combinations that work. Familiarity with the cultural needs and growth habits of different plant species and cultivars can go a long way to better choose combinations that will work well over the long run.

Group plants with similar cultural requirements.

Light

Combine plants that share similar light requirements. Plants that do well with half a day or more of full sun include ageratum, marigold, petunia, and zinnia. Plants that need to be shaded most of the day include common impatiens, tuberous begonias, and fuchsia. Higher and lower light-requiring plants can sometimes be successfully combined. For example, combine larger, higher light-requiring plants that cast shade over smaller, more shade-tolerant plants. Temperature preference is often closely allied with light requirement. Heat loving annuals like gazania and moss rose also prefer full sun and are also more tolerant of drying out between waterings.

Water

Combine plants with similar moisture needs. Plants that can tolerate or prefer being kept on the dry side include gazania, moss rose, verbena, and zinnia. Those that prefer to have a consistent supply of moisture include coleus, tuberous begonias, and fuchsia.

pH

Often not thought about, the pH of the growing medium influences nutrient availability and other aspects of plant growth. In addition to the starting pH, pH can change over time in response to water quality and type of fertilizer used. Often the pH of city water is elevated to a pH of over 7.5 with sodium hydroxide or other bases to protect metal pipes from slowly deteriorating. High water pH can elevate potting medium pH over time. The rate of pH increase is dependant on some properties of the water (dissolved minerals) and the particular planting medium and its pH buffering ability. Knowing your pH will aid in selecting better adapted plants. For instance, geraniums, celosia, and marigolds prefer a higher pH (alkaline) and petunia, pansy, and bacopa a lower pH (acidic). It often becomes clear in mixed plantings of for instance petunia and geranium if the pH is shifting more towards the acidic or alkaline side based on which is performing better.

Combine plants considering their growth and flowering traits

Vigor

Using plants with similar growth rates helps to prevent slower growing plants from being smothered by vigorous neighboring plants. A very vigorous spreading petunia cultivar, for instance, may choke out a neighboring compact-growing ageratum or geranium. One factor that influences growth rate is response to fertilization. Many of the more expensive, specialty annuals like spreading petunias, bacopa, and sun or solar coleus, for instance, are heavy feeders and can grow quickly in a nutrient-rich environment.

Growth habit

Some plants have looser, more open, airy growth habits and tend to intermingle and flower better with each other, while other plants have denser growth and more difficulty growing with other plants. Growth habits also vary between upright, mounding, or trailing. Loose-growing trailing verbena and bidens cultivars can intermingle and flower well together, while geraniums, tuberous begonias, spreading petunias and bacopa cultivars tend to make a thick, mounded plant or a relatively dense mat of growth capable of crowding out neighbors. Upright, taller growing plants are often placed towards the center or back of a container, while spreading or trailing plants are placed near the edge of the container where they can grow over the containers edge. Understanding growth patterns of plants can help in determining placement in the window box and how close to plant different species so each is showcased, not smothered.  Window boxes typically have cascading types of plants planted near the edge that can spill over, while more mounded or upright plants are planted closer to the window.

Flowering time

Some plants flower continually, while others have more limited periods of bloom. For instance, osteospermums (cape or sunscape daisies), snapdragon, and pansies reduce or stop flowering during the heat of summer, but flower again once the temperatures cool down. Mixing plants so that something is blooming at all times during the season can help enhance season long beauty.

Vast plant selection options

Annuals

Annual bedding plants are traditionally used for window boxes since plants are typically discarded after each season and replanted in the spring. For many traditional annuals there are newer, compact versions of old favorites that are more amenable to confined spaces. For instance, the profusion series of zinnias are more compact and more amenable to confined places than the old fashioned taller zinnias.  The Profusion and Pinwheel series of zinnias are crosses between the small, disease resistant Mexican zinnia (Zinnia angustifolia) and the traditional large flowered garden zinnia (Z. violacea, Aka  Z. elgans).  More colors and doubled flowered versions have been added to these series.

Perennials

Many plants used as annuals in Minnesota are actually perennials in their native climate. Examples include geraniums and fuchsias. Also consider using hardy Minnesota garden perennials in containers. At the end of the season they can be nestled into a perennial bed to extend their value, or discarded as an annual.  Due to window boxes being exposed to the air from all sides during winter, typically Minnesota hardy plants may not overwinter if left in a window box.  Root are typically less hardy than stem tissue and the strong insulation ability of soil and snow prevents roots from experiencing winter air temperatures. Frequently-used, Minnesota-hardy perennials for containers include lamium (Lamium maculatum, L. galeobdolon - plants are low and spreading and variegated foliage looks great even when not in flower) and golden-leaved creeping Jenny or moneywort (Lysamachia nummularia ‘Aurea’). Compact versions of standard perennials that have a long flowering season make great choices as well and include astilbe ‘Sprite’, heliopsis ‘Tuscan Sun’, and scabiosa ‘Butterfly Blue’.

Woodies

Compact versions or carefully pruned specimens of an especially ornamental woody plant can make a great accent or focal point in a container. Some woody plants have especially interesting flowers, foliage, or texture. One potential option includes the new compact, variegated weigela, ‘My Monet’.

Uncommon foliage

Foliage color, shape, texture, and size all can add unique elements to a design, even if the plant never blooms. In addition to traditional foliage plants such as dusty miller, coleus, alternanthera, and dichondra, consider using herbs and vegetables with interesting foliage color and texture such as fennel, parsley, and rosemary. Gold, purple-black, and variegated cultivars of ornamental sweet potatoes have become very popular and are quite versatile in containers. One unique consideration with sweet potato is that in relatively small window boxes the tubers it produces can easily crowd out other plants as the season progresses.

Creating one or more window boxes dedicated entirely to herbs is also a great option, especially window boxes conveniently located outside a kitchen window or bedroom or other window where the fragrances can particularly be enjoyed.  Many herbs have a compact and/or spreading growth habit and would work well in a window box and include lavender, creeping rosemary, basil, some of the mints (like chocolate mint), and thyme.

Basic container garden growing recommendations

Make sure window boxes have holes for drainage and are also a suitable size to accommodate your chosen plants as they grow throughout the season. Often too small a container is chosen or too many plants are put in a container at planting time which leads to overcrowding problems by midsummer. Look beyond how full, colorful, and proportional the pot looks at planting time and envision the container and size of the plants throughout the rest of the growing season. The larger the container typically the better (heavier containers will need stronger anchoring). Larger containers is beneficial for added root development and also allows for greater reserves of moisture and nutrients and allows for extended time between thorough waterings.

Potting medium needs to have a balance of both moisture retention as well as porosity so oxygen can get to the roots. If the medium does not have good aeration and frequently becomes waterlogged, then roots can be deprived of oxygen, slow in growth, and more likely rot. On the other hand, a medium that is too porous can be challenging to water frequently enough to keep moist. Most standard, commercially sold mixes for containers are high in organic matter (often containing peat moss, compost, and/or bark) and may contain perlite or vermiculite for added porosity. Instead of filling up a window box with planting medium, another option is to place a series of potted plants into an empty window box.  This allows great flexibility to replace plants and to have a spot to set some plants that typically serve as houseplants during the summer months.

Containers can dry out quickly, especially on hot windy days and after plants grow in size and their demand for moisture increases. To help with watering needs, leave at least half an inch from the surface of the media to the rim of the container when planting. This will provide space for water to puddle and then slowly soak in without quickly running off when you water.

Water crystals or beads (hydrogels) are commonly found for sale as a means to help hold moisture in potting media. Water beads are dry crystals that can absorb multiple times their weight in water. They can be hydrated and mixed into the medium before planting. Although water beads or crystals can hold water, research conducted by Dr. Jeff Gillman at the University of Minnesota and others suggest that they may be holding onto water too tightly and not benefiting plants because the water they are holding may not be readily available to plant roots. Work continues to compare different types of hydrogels.

The options for developing beautiful window boxes seem almost limitless, just like our garden beds, and they provide a wonderful, creative, and versatile accent to our home. If you haven’t tried window boxes yet, hopefully this article will inspire you to give them a try this season.

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If you are looking to get fresh ideas for your garden, to see the latest in University flower, fruit, and vegetable varieties and accompanying research for yourself, or just to experience a beautiful, accessible garden, you will want to visit the 6-acre Master Gardener Education & Research Display Garden! There are over 25 different display and trial gardens to see.  They are well-labeled and a fantastic resource for Minnesota gardeners.

The garden is free to the public and open daily (sunrise to sunset) with plenty of free parking available. It is located on the South side of Highway 46 in Rosemount, Minnesota, just two miles East of Highway 3. It is within and part of the 5,000 acre UMore Park (University of Minnesota Outreach, Research, and Education Park). The garden started in 2001 with the purpose of being a display garden serving the public through education and research.  It is located in the Southeast metro and has a much different flavor and a unique purpose compared to the Minnesota Landscape Arboretum located in the West metro. 

In 2003 Master Gardeners became involved in the project and led the way to establish and bring to fruition the many wonderful theme gardens that support the mission of public education.  Much of the plant materials and hardscape supplies within the garden have been possible from the generous donations of many individuals and businesses.  The 6 acre demonstration / trial garden serves as an outdoor learning center.  Approximately 130 Master Gardeners are currently involved in the ongoing development and maintenance of the garden. This is the first garden of its kind in the nation and it has already won prestigious national awards. Learn more about the garden.

One of the multiple educational programs at the garden is Tuesday Evenings in the Garden.  Each Tuesday night throughout the growing season there is a class from 6:30-8:00PM.  Classes begin at the gazebo. Click here for registration information.  Pre-registration is recommended to help instructors prepare an appropriate number of handouts and have enough supplies ready for hands on projects.

The 2009 Tuesday Evenings in the Garden Classes are:

May 26th Iris – A Kaleidoscope of Color – Lee Kaibel
This hands-on class will focus on dividing bearded iris and comparing bearded and beardless iris and how they are used in gardens.  Participants will learn how to care for each of these beautiful plants and view many of the approximately 200 varieties of iris in various stages of bloom in the display gardens at UMore. $10.00

June 2nd Luscious Tomatoes – David Zlesak
Growing delicious, fresh tomatoes at home is easy and can be richly rewarding.  Come and learn about basic types/categories of tomatoes and proven cultural techniques to help us get the most out of them.  There will be tomato plants to take home! $10.00

June 9th Herbs by the Kitchen Door – Shari Mayer
Spice up your cooking by creating a potted herb garden you can keep by the kitchen door. All supplies are included. $25.00

June 16th Rain Gardens – Joanne Sabin
Learn how to create a beautiful garden of native plants that captures rain runoff, protecting our lakes and rivers. $10.00

June 23rd Fruit Trees – Bob Condon and Sally McNamara
Get the know-how you need to grow productive fruit trees in Minnesota. $10.00

June 30th Got the Blueberry Blues? – Warren Banks
Warren covers the cultural techniques needed to grow this handsome shrub, both for fruit production and landscape appeal. $10.00

July 14th Wildflower Gardens – Roxanne Beseman and Corinne Johnson
Learn to grow wildflowers and add a touch of delicate beauty to your garden. $10.00

July 21st Nonstop Lilies – David Zlesak
There are several classes/types of lilies we can successfully grow in Minnesota.  With a little care we can select types/varieties of lilies so as to have lilies in flower during most of the growing season!  Come learn about different lily categories and cultural techniques to make the most out of these amazing garden showstoppers. $10.00

July 28th For the Birds – Suzanne Hamann and Deb Morrison
This class covers plantings that will attract a wide variety of birds to your garden. $10.00

August 4th Toadstool Garden Art – Cheryl Mann
Create a lightweight hypertufa toadstool and add a whimsical touch to your garden. $25.00 (includes supplies)

August 11th Square Foot Gardening – Chris Johnson
Learn how to grow the maximum number of vegetables in the smallest space. $10.00

August 18th The Dirt on Soil – Elizabeth Spedaliere, Deb Snow and Kathy Bonnett
Want to know what’s happening beneath the soil surface? This class covers soil types, nutrients, and water retention. $10.00

August 25th Stepping Stones – Joyce Clarin
Create a cement stepping stone with a unique, natural design. $25.00 (includes supplies)

September 15th Fall Pots – Kathy Bonnett, Deb Snow and Elizabeth Spedaliere
Replace faded annuals with corn stalks, dried flowers and grasses. No watering required! (Supplies included. Bring a soil-filled pot.) $25.00

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In some areas of the state, lawns have received ample moisture this spring to maintain good growth and color while others have been quite dry; Twin Cities included.  In fact, supplemental lawn watering has already begun in many areas around the Twin Cities.  In most cases, it will take about 1.0 inch of water per week to keep Kentucky bluegrass lawns green and actively growing through the summer months.  One question frequently asked by homeowners is “How do I know how much water my sprinkler or irrigation system is putting out?” 

Determining how much water is being supplied by a sprinkler is not a complicated process.  Simply place several small flat bottomed containers within the distribution pattern of a sprinkler.  Tuna fish cans work well for this measurement. A simple rain gauge or two placed within the water pattern will also work so long as the gradations are close enough to measure small amounts of water.  Turn on the sprinkler as you would to normally water the lawn and leave it on for an hour.  After an hour, measure the depth of water accumulated in the bottom of the container.   For example, if the average accumulated water in the cans were ¼ inch for that hour, then you can assume that your set-up is putting out about a ¼ inch of water per hour.  Looking at the amount accumulated in each container will also be helpful in determining the uniformity of water distribution and may suggest the amount of overlap needed to ensure all areas receive equivalent amounts of water.  With automated systems, place the containers within the distribution pattern and measure the amount of water accumulated after a cycle for that part of the yard is completed.  This will give you the amount of water be applied for that particular cycle. 

By early to mid-June, many of our annual broadleaf lawn weeds will be starting to germinate.   One of the best times for controlling these weeds is in this early growth stage before they have started to mature.  Examples of our common annual broadleaf weeds include prostrate or spotted spurge, erect and prostrate knotweed, lambsquarter, redroot pigweed and purslane.  The clover like plant, black medic as well as yellow woodsorrel are usually considered annuals although some plants may overwinter and behave like a biennial or short lived perennial.   Taking a few minutes to walk your lawn in order to determine when some of these weeds may be germinating allows one to easily remove them by hand and/or treat them with an herbicide.  Remember, removing and/or treating plants with an herbicide is much more efficient when they are small, even at the lower application rates stated on the product label. 

For those sites that are irrigated, regular mowing will be required throughout the growing season.  Maintaining heights at about 2.5 inches should be adequate for most home lawns.  For those lawns not receiving irrigation, mow only as needed and required by the growth of the plant.  Try to follow the general rule of thumb to not remove more than 1/3 of the height at any one mowing.  For example if you are maintaining a height of cut at about 2.5 inches, then mowing should be done when the height reaches about 3.5 – 4.0 inches. 

While most walk-behind rotary mowers adjust mowing heights by resetting the four wheels to the desired height, it is occasionally a good idea to see how close that setting really is to the actual height of cut.  The easiest way to do this is to simply take a ruler and gently push it through the turfgrass canopy until it rests firmly on the lawn/ground (may not be actual soil) surface.  Then look across the grass plants just in front of the ruler and see what the height is.   For example, if the ground is firm then mower wheels will ride higher and consequently the height setting will more closely approximate the actual cutting height.  However, where the ground is soft or there is a significant thatch layer present, the wheels will sink more deeply into the lawn and hence the mowing height is actually less than the wheel settings would indicate.  In fact, where there is significant thatch present mower wheels can ride so much lower that the lawn surface between the wheels is actually scalped.  Remember to take the time to adjust your mower correctly, periodically verify that the mower height settings are actually providing the desired height of cut, and always mow with a sharp blade. 

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As the season warms up and new leaves reach their full size a few gardeners are noticing unsightly spots in a wide variety of plants.

What are these spots?

Many of the spots that gardeners are seeing are caused by fungal or bacterial pathogens infecting the leaf tissue. There are a few look a likes, however, so gardeners should pay attention to the details. Fungal and bacterial leaf spots are typically randomly scattered across the leaf. There are often several sizes of leaf spots because the spots get bigger as the pathogen grows. In addition leaf spots caused by a pathogen start out on one leaf and eventually spread throughout the plant or to other plants. A gardener may notice fluffy white cobweb like fungal growth, powdery spores or other signs of the pathogen in the spots themselves.

Spots that are all one size, do not grow and spread, or occur in a specific pattern are not likely caused by fungal or bacterial pathogens. Many gardeners confuse leaf damage caused by fourlined plant bug with a fungal leaf spot disease. See the article, Fourlined Plant Bugs Are Now Active, in this issue for more information about fourlined plant bug. Notice how the spots caused by fourlined plant bug are all the same size.

Where did these spots come from?

Fungal and bacterial leaf spot pathogens can come into the garden from a variety of places. Some are blown in on the wind. Others come in on infected plants. Most survive from season to season in last years infect leaves. Splashing rain or spring winds carry the pathogen onto the newly emerging leaves.

What to worry about?

Leaf spot diseases are not a serious threat to the health of the plant if they do not result in major leaf loss or discoloration. If the leaves are mostly green and still attached to the plant, they can still undergo photosynthesis and provide food for the plant despite a few spots. Many leaf spot diseases fall into this category and require no management.

Leaf spot diseases that result in defoliation or discoloration of the majority of the leaves should be taken more seriously. For example black spot on rose can seriously injure a plant because in addition to spots, the black spot fungus causes leaves to turn yellow and fall off. This reduces the energy available to the plant and can result in reduce growth, flowering and winter survival. Gardeners should consider using a combination of management strategies to slow the spread of these pathogens.

What can you do?

There are several basic practices that a gardener can implement to reduce the amount of leaf spots that occur in the garden. Most fungal and bacterial pathogens need moisture or very high humidity on the leaf surface in order to start a new infection and to produce new spores or bacteria. Many management strategies focus on reducing leaf wetness.

• Tolerate leaf spots if the majority of the leaf is green and no major leaf loss is occurring.
• Use drip irrigation or a soaker hose to water plants instead of sprinkler irrigation.
• If sprinkler irrigation is the only option, water in the morning so that leaves dry quickly in the sun.
• Space plants for good air movement in the garden. This will help leaves dry quickly after rain or dew.
• Split dense, overgrown perennials to improve air movement through the garden.
• Mulch garden plants to reduce humidity.
• Do not work in the garden when the leaves are wet. Wait until plants have dried to prevent accidentally moving the pathogen on your hands or tools.
• Remove last year’s plant debris from the garden.
• If only a few leaves are infected, pinch off infected leaves and remove them from the garden. Never remove more than 1/3rd of a plants leaves or you will do more harm than the pathogen!
• If a plant is severely infected, look for a disease resistant variety to replace it.
• If all of the management strategies above do not reduce the leaf spot disease to an acceptable level, consider protecting plants with a fungicide. Always read and follow all instructions on the label any time you apply a pesticide!

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By now, I am sure that everyone has heard about the confirmed emerald ash borer (eab) find in St. Paul on May 14 near Hampden Park (northeast of the intersection of I-94 and Highway 280).  There are lot of questions being asked by homeowners about what to do, especially about insecticides.

First, if you are further than 10 to 15 miles from St. Paul, we do not suggest you treat your ash.  Without being closer to known eab infestations, you are very likely just wasting money and insecticides.

But if you are within this 10 to 15 mile radius, treating your ash is a consideration.  However, this issue is more complicated than just what product to use.  There many factors to consider.  There is a new fact sheet written by entomologists from Michigan, Ohio, Indiana, Wisconsin, and Illinois that discusses this topic in detail.  You can find this publication on the Extension Emerald Ash Borer web page. Look under Resources and then under Management.  This page also contains a lot of other important information concerning eab.

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There have been reports of sawflies defoliating azaleas recently.  The larvae hatch during May and are active into June.  They are smooth, slender and grow to about 3/4 inch long.  They are light green which allows them to blend in really well with the azalea leaves, making them difficult to see. 

It isn’t unusual for gardeners to overlook azalea sawflies when they first start feeding.  Often the first symptom of their presence is chewed leaves or droppings on the foliage.  Azalea sawflies start feeding on the edge of leaves and work their way down to the midrib.  On heavily defoliated branches, all that remains is just a series of veins sticking out, resembling a skeleton.

It is important to detect azalea sawflies soon after they hatch to minimize their damage to plants.  In many cases now, these sawflies are already finishing their feeding making it too late to treat them.  However, if most of the sawflies you are finding are still relatively small, there are several options you can consider to manage them.  If there are not many larvae present, just remove them by hand, throwing them into a bucket of soapy water to kill them.  Particularly inspect partially chewed leaves or leaves next to areas where you find droppings to help find larvae. 

You could also consider using an insecticide.  If you wish to use a low impact product, try insecticidal soap.  To be effective, you need to hit the larvae directly with the spray.   Also, there isn't any residual activity so you won't kill sawflies that walk onto treated leaves later. Another effective, low impact product is spinosad.  Residual garden insecticides are also available, such as bifenthrin, permethrin, and carbaryl.

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If you are out in your garden and notice small, uniformly sized spots on your favorite perennials, be suspicious of fourlined plants bugs.  Fourlined plants bugs hatch in late May or early June and feed until early to mid July.  Newly emerged nymphs are about 1/16th inch long and bright red.  As they grow larger, they develop black wing pads which eventually develop yellow stripes.  Eventually they mature into 1/4 - 1/3 inch long insects with a reddish orange head and greenish yellow wing covers with four black stripes.

Fourlined plant bugs feed on a wide variety of perennials, especially plants in the mint family.  They are also known to feed on various shrubs.  They use piercing-sucking mouthparts to feed on sap from the leaves which creates sunken, usually round spots.  These lesions are of a similar size and are regularly distributed which helps to distinguish this damage from leaf spot diseases.  Fourlined plant bug injury can also distort, cup, or curl leaves.  This damage normally does not kill plants, but it can affect their appearance.

When managing fourlined plant bugs, it is important to discover their presence as early as possible to minimize injury to plants.  If you are finding just a few fourlined plant bugs, you can just crush the insects.  Otherwise, there are a variety of residual insecticides, including permethrin, bifenthrin, cyfluthrin, carbaryl, and malathion, that can be used reduce fourlined plant bug numbers.

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Some residents have discovered masked hunters in their homes recently.  A masked hunter is a ½ - 5/8 inch long, dark colored insect.  It has a moderate sized body with slender legs and medium length antennae.  A masked hunter, a type of assassin bug, gets it name from the fact that the immature nymphs cover themselves with dust and debris to help conceal themselves, thus becoming camouflaged.  Both adults and nymphs are predators, feeding on other insects.

Masked hunters are only nuisances when they are found in homes.  However, they are known to bite people to protect themselves if they are mishandled or accidently trapped against the skin.  In fact, I received a couple of reports of bites this spring.  Bites can cause some pain but they are usually short-lived.

If you see a masked hunter in your home, the only necessary control is to physically remove the insect.  Because of the potential of bites be careful when picking them up.  You can protect yourself by placing a jar or some sort of container over the masked hunter and then sliding a piece of paper under it.  Now you can flip the jar without the insect escaping and you can release the insect outside.  Because masked hunters are infrequently encountered, it is not necessary to use insecticides to protect your home from them.

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June is an amazing month in Minnesota- perhaps the most enjoyable one of all with generally nice weather and the fast rate of growth of plants in our gardens.  It is definitely a month when there is a lot to enjoy in our gardens.  Early season vegetables are ready for harvest and our ornamental plants are growing strong.  In the midst of everything going on, please don’t forget to take time to relax and “smell the roses”.

Danger of frost and very cool night time temperatures are finally over for most parts of Minnesota.  This means we can put out our warm season vegetables and flowers that are sensitive to chilling injury.  This includes: tomatoes, peppers, cucumbers, squash, melons, cannas, coleus, and impatiens.  Perhaps we have put some of these crops out earlier and protected them from frost.  It is amazing how just cool night time temperatures in the high 30’s and low 40’s F can stunt growth of warm season crops. Warm season plants put out in our gardens now can outgrow those that may be suffering from chilling injury from our excitement to get them in early even if we protected them from frost. 

Consider staggered, succession plantings of garden vegetables like bush beans and loose leaf lettuce to have a continual supply. Consider planting more each week or every other week. Some loose leaf lettuce varieties have been selected to have greater heat resistance and less propensity to bolting than others and are better choices during our warmer summer months.  Succession planting is a great idea as well for some flowers with a short flowering period such as gladiolus.  Plant gladiolus corms at two week intervals up through the middle of July in order to enjoy blooms over an extended period of time.

Now is a great time to prune many of the recently spectacular spring flowering shrubs, if needed.  Light to moderate pruning can be done to shape them, rejuvenate them, or simply to overall reduce their size.  Such shrubs include forsythia, early blooming spireas, flowering almond, and earlier flowering lilacs.

June is a very active month of growth for plants. For most plants an ample supply of water typically means 0.75 to 1.0 inch of water per week. If rainfall is not sufficient, try to supply the remainder through irrigation. Consistent, deep waterings are especially important for new or recently planted trees and shrubs, newly planted seeds and transplants, and very sandy soils that do not retain moisture well.

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Happy gardening!

David C. Zlesak, Ph.D.
Editor
Extension Educator