Yard & Garden Line News
Volume 7 Number 6                                                               May 1, 2005
Features this issue:

Gardening from the Surface Downward
Mystery Insect
Some Noteworthy Herbs
Morel Relativity
May Garden Calendar
Editorial Notes

Gardening from the Surface Downward
Carl Hoffman, Horticulturist, Stearns Co. Extension



Soil triangle.
What is this stuff called dirt?

An old gardener's joke goes that "soil" is what we grow our plants in, and "dirt" is what's under our fingernails. Whether you call it soil or dirt, we are talking about the dynamic substance in which all our plants grow. Soil can be very different from one location to another, but generally consists of organic and inorganic materials, water and air. In 1675, John Evelyn, a great diarist, wrote that in his opinion, there were no less than 179,001,060 different types of earth!

About 90 percent of the soil is composed of tiny bits of rocks and minerals from which the soil is formed. These particles are referred to as sand, silt or clay, depending on their size. Most soils contain a mixture of these three types of particles. The proportion of each of the different sized particles it contains determines the texture of the soil. Because these components are largely unalterable, there is not much you can do to change them. Soils are often classified according to the major particle component as, for example, a sandy soil or a clay soil. If you are lucky enough to have a loam soil, you have a soil that has nearly equal proportions of sand, silt and clay. Loam soils have better drainage than clay soils while having better water and nutrient holding capacities than sandy soils.

The remaining 10 percent of the solid part of the soil is the organic fraction. Although only a small part of the total soil, it has a tremendous influence on the soils ability to support plant growth. This is a very dynamic part of the soil in that it is constantly undergoing change. The organic constituents of soil include living organisms, including plant roots, animals, insects, bacteria and fungi, as well as dead plant residues and other wastes. The way you manage your soil has a great influence on the amount and quality of the organic matter it contains, but we will talk more about that at another time.

By volume, an average soil is 50 percent solid, 25 percent water and 25 percent air space. If we add the water and air space together, we find that the soil is 50 percent pore space, which is the place that plant roots actually grow. When we think about it, plant roots actually grow between the soil, not in the soil. When soil is either compacted or waterlogged, this pore space is reduced. The structure of the soil, which is the way the soil particles are grouped into clumps called aggregates, also affects pore space. A fine textured soil like a clay soil has small structural units and, therefore, small pores which affects aeration and water infiltration.

What does all this mean for the gardener? Soil structure and texture has a direct affect on soil temperature, water holding capacity and nutrient holding capacity. Sandy or course textured soils warm rapidly in the spring and remain amenable to cultivation even when wet. Therefore, they are especially desirable for early vegetables and flowers and for root, bulb and tuber crops. Water soaks into sandy soils readily, but such soils have low water and nutrient retaining capacities and are likely to be droughty and infertile. Clay or fine-textured soils warm and dry slowly and cannot be worked when wet. Although clay soils absorb water slowly, they retain moisture and nutrients well, so plants growing in them do not need irrigation or fertilizer as frequently as those growing on sandy soils. Good drainage is a requisite for many plants and, therefore, clay soils often need to be amended to increase drainage.

A soil that is ideal for growing flowers and vegetables is loose and easily workable. A sandy-loam soil that is well drained, fertile and contains abundant organic matter would grow flowers and vegetables that would be the envy of the neighborhood. Because most of us do not have this type of soil in our gardens, the soils need to be amended.

Why and How do You Amend Soil?

I have stated that a sandy-loam soil that is well drained, fertile, and contains abundant organic matter would grow flowers and vegetables that would be the envy of the neighborhood. Does that mean that those of us that garden in sandy or clay soils must settle for second rate gardens?

The answer to that question is an emphatic "no"! Fortunately, we can amend those soils to make them produce flowers and vegetables that rival those produced on "ideal" soils. You are probably thinking, "here we go again, 'amending soil'; another catch phrase like 'evenly moist' or 'tree decline'?!"

Simply stated, amending the soil means adding materials, called amendments, to the soil to improve its drainage, pH, fertility, texture, and moisture holding ability. Most soils need to be amended somewhat to provide an environment in which plants will thrive. The goal is to provide the best possible environment for the roots of the plants we wish to grow.

There are two broad categories of soil amendments: organic and inorganic. Organic amendments come from something that was alive while inorganic amendments are either mined or man-made. Organic amendments include sphagnum peat, wood chips, grass clippings, compost, leaf mold, manure and sawdust. Inorganic amendments would include vermiculite, perlite, gravel and sand. Organic amendments increase soil organic matter content and offer many benefits. Organic matter improves soil aeration, water infiltration and both water and nutrient holding capacity of the soil. In addition, many organic amendments contain plant nutrients and act as organic fertilizers as well as provide an important energy source for bacteria and beneficial fungi in the soil.

Amending the soil is not the same as mulching, although many mulches are also used as soil amendments. A mulch is left on the soil surface where it is used to reduce evaporation and runoff, inhibit weed growth, and create an attractive appearance. An amendment must be thoroughly mixed into the soil to be effective. If it is left on the surface it will do little to improve soil structure and if it is merely buried its effectiveness is reduced and it will interfere with water and air movement and root growth.

If you use wood products such as wood chips, shredded bark or fresh sawdust and even straw or leaves that have not been composted as a source of organic matter, you should also apply a nitrogen fertilizer. Microorganisms in the soil use nitrogen to break down these materials, which will cause a temporary nitrogen deficiency in your soil if additional nitrogen is not added at the same time as the organic material. The greatest chance of nitrogen depletion occurs with sawdust because it has a greater surface area than wood chips.

Sphagnum peat, compost, composted animal manures (no pet feces!) are excellent soil amendments for sandy and clay soils, both of which are a challenge for gardeners. Coarse, sandy soils dry out very quickly because of their rapid drainage that also encourages leaching of important nutrients, making it difficult to maintain fertility. Organic matter will enhance the sandy soil's ability to hold needed water and nutrients. Clay soils often remain wet well into the growing season and can become compacted if worked when wet. Compaction of the soil makes it difficult for air and water to reach the plant roots. Clay soils also become sticky or slippery when wet and then form dry hard clumps when dry. The addition of organic matter improves a clay soil's structure, improves drainage, reduces stickiness and decreases the amount of compaction that occurs when clay soils are worked. Do not add sand to clay soils as it will create a soil structure similar to concrete. When amending clay soils, it is essential that the organic material, and possibly some perlite, be thoroughly mixed with the existing soil to a depth of 12 inches. If the amendments are not mixed thoroughly with the soil, layering will occur and water movement in the soil will be compromised.

The amount of organic matter to apply at any one time is going to depend on the organic content of the soil. When preparing a new bed or border, place 3 to 6 inches of your chosen organic matter on the surface and dig or till it into the soil to a depth of 10 to 12 inches. If the organic content of your soil is less than 3 percent as determined by a soil test, use the upper levels of the recommended amount. Additional organic matter should be added to the soil every year. Think of your soil as living, something that has to be fed and cared for. The inorganic substances break down very slowly, but the organic mater disappears rapidly, eaten by the billions of leaving creatures in the soil itself.

Soil pH-ertility



pH scale.
I have been relaying some facts and hints regarding the structure of our garden soils and some ways in which we can amend our soil to improve its water holding capacity, aeration, and drainage so that it supports good plant growth. If our goal is to provide the best possible environment for our plants to thrive, we still aren't finished! I will conclude by discussing ways in which we can affect the fertility of our soils and correct the often overlooked soil pH.

If we want to grow robust plants in our yard or gardens, we can't overlook soil pH. The pH of a soil is a measure of its acidity of alkalinity. Technically pH is a measure of the hydrogen ion concentration in the soil measured on a logarithmic scale from 1 to 14, but for our purposes all we have to know is that a pH of 7 is neutral, a pH below 7 is acid, and a pH above 7 is alkaline. Soil pH affects the availability of nutrients to plants and the activity of microorganisms in the soil. The availability of the three major nutrients; nitrogen, phosphorus and potassium, decreases as the soil becomes more acidic while the availability of phosphorus and many micronutrients, especially iron, decreases as the soil becomes more alkaline. You may be familiar with a condition called iron chlorosis in which the younger leaves of trees, shrubs and other plants develop yellow leaves with green veins. There is plenty of iron in most soils, but in alkaline soils the iron becomes tied up and is unavailable for plant uptake.

Most commonly grown fruits, vegetables, flowers, trees and shrubs grow best in soils with a pH between 6 and 7. Some important exceptions include blueberries, azaleas and rhododendrons which are acid loving plants and require a pH between 4.5 and 5.2. Blue hydrangeas require a pH of 5.0 or lower to produce the blue flower color we covet.

Do not attempt to correct the pH of your soil without a soil test. Many of the how-to garden books and magazines we read are written by authors who live in eastern United States where the soils are naturally acidic. Therefore, a common recommendation by these authors is to apply lime, a material that is commonly used to raise the pH of soil, to yards and gardens every spring. However, in many areas of Minnesota, especially in urban areas, the soil pH is neutral or even slightly alkaline and will NOT need lime. Applying lime when it is not needed can cause micronutrient deficiencies associated with alkaline soils.

Elemental sulfur, iron sulfate and aluminum sulfate are materials that can be used to lower pH for acid loving plants. The popular "Endless Summer" blue hydrangea has shown some aluminum toxicity and it is recommended that if aluminum sulfate is being used to lower the pH of the soil, it not be applied to the soil until the second year after this hydrangea is planted.

In addition to the soil pH, a soil test will also provide information on the nutrient content of our soil as well as a fertilizer recommendation for nitrogen, phosphorus and potassium. With a soil test, we can apply only the amount of fertilizer that is needed to nourish a healthy plant and avoid any unnecessary excess fertilizer that could become a pollution problem in our aquifers, lakes and streams.

The University of Minnesota Soil Testing Laboratory is a reliable and efficient place to have your soil tested. A soil testing kit, which contains an information sheet describing how to take the sample and a sample bag to transport the soil, can be obtained from your county extension office, the Soil Testing Laboratory at 612-625-3101, or some of the local nurseries and garden centers. The current cost of a regular soil test is $15.00. The regular test includes a test for phosphorus, potassium, pH, organic matter content and a texture estimate. In addition to the test results, you will receive fertilizer recommendations to correct any deficiencies your soil might have. A test for nitrogen is not conducted with the regular test because nitrogen is so mobile in the soil that the content changes over the course of a year. You will receive a nitrogen recommendation on your test report that is based on a number of factors including the organic matter level, the type of plant you propose to grow or have grown on the site and, in the case of lawns, the amount of watering you do and the removal of clippings.

Nitrogen, the element necessary for vigorous vegetative growth and development, is most often in short supply in the soil. Phosphorus is necessary for good root development and for flower, fruit and seed production. The role of potassium is not as well understood, but we know that it is important for overall plant health and vigor. For this reason, these are the three nutrients that we almost always find present in commercial fertilizers. Commercial fertilizers, whether organic or inorganic, always have three numbers printed on the bag or container. These numbers are called the analysis of the fertilizer and represent the percentage of nitrogen, phosphorus and potassium (or N-P-K) in the product. The remainder of the product is an inert carrier.

You will have to decide if you are going to use an inorganic or an organic fertilizer. To help you make your decision, I will briefly discuss some characteristics of each of these fertilizer forms. Inorganic fertilizers, often called chemical fertilizers, usually have a higher nutrient analysis than most organic fertilizers and are less expensive. The nutrients in an inorganic fertilizer are in a form that is readily available to plants and the growth response will be faster. Organic fertilizers contain nutrients in forms that must be chemically changed in the soil before the plants can use them. These nutrients, although not immediately available, are usable to plants over a longer period of time. Some inorganic fertilizers will contain nutrients in both readily available and slow-release forms. Organic fertilizers are less likely to burn plants and often contain several micronutrients in addition to nitrogen, phosphorus and potassium. The relative merits or fault of each of these forms is often debated in relation to the effects on our environment. It is the misuse, not the use, of either of these products that has a negative effect on the environment, making a soil test and strict adherence to the recommendations imperative.

Growing healthy, beautiful, productive plants involves attention to many cultural details. Fertilization is just one of the details and should not be considered a cure-all for all gardening problems. When properly used, fertilizers are extremely valuable in bringing good gardening results. However, fertilizers cannot correct or improve poor soil structure or compensate for an incorrect pH. The use of fertilizers is just one of a number of integrated gardening processes that lead to gardening success. By combining fertilizers with organic matter and other necessary soil amendments and giving attention to the cultural requirements of the plants you are growing, you can have a yard and garden that is the envy of the neighborhood.

Mystery Insect
Jeffrey Hahn, Assist. Extension Entomologist

Rat-tailed maggot.
Source: Unknown.
People may sometimes encounter this unusual-looking insect larva. It's legless, has a cylindrical body and lacks any obvious head. It is about 1/2 - 3/4 inch long and possesses a very conspicuous, characteristic ‘tail'. Because of this long tail, this odd looking insect is known as a rat-tailed maggot.

This insect larva belongs to a group of flies known as syrphid flies. Syrphids are also known as flower flies or hover flies. They mimic bees or wasps and are very common on flowers and plant foliage. Despite their threatening appearance, all syrphid flies are harmless to people and are actually beneficial because they help pollinate plants. A rat-tailed maggot adult, sometimes referred to as a drone fly, resembles a honey bee.

Rat-tailed maggots are found in stagnant water that is high in organic matter. They are typically found in manure pits, polluted drainage ditches and water tanks, pools of runoff around manure mounds, and similar sites. They are particularly common around farms and fertilizer plants. Also look for them occasionally in urban areas where they can be associated with septic tank runoff or similar pools of stagnant, polluted water. There is also a reference of rat-tailed maggots associated with very wet, decaying plant matter.

The long ‘tail' on a rat-tailed maggot is actually a breathing tube that allows the insect to stay submerged in the water. This tube is normally about 3/4 inches long, but the insect can telescope it out to several times the length of its body. Rat-tailed maggots apparently feed on organic particles that are floating in the water. Although they live in aquatic environments as larvae, they crawl out of water and seek dry sites to pupate. Sometimes they crawl to dry land by the 100's. This mass movement can be a nuisance to people, especially when they travel into adjacent buildings, but they are otherwise harmless.

Larvae are typically found during mid to late summer. However, a homeowner found an individual larva in a yard during mid-April this year. It was described as crawling and inching its way along the ground. The literature suggests that rat-tailed maggots overwinter as an adult or as a pupa. It wouldn't seem likely that one could survive outdoors as a larva so it is not clear what circumstances allowed this individual to be found so early this year.

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

Some Noteworthy Herbs
by Shirley Mah Kooyman


Lavender.
Photo Credit: USDA
We've all heard of the AAS winners and the Perennial Plant of the Year, so is it any surprise that there's also an Herb of the Year? Every spring, since 1991, International Herb Association, http://www.iherb.org/, has named an Herb of the Year. Here are profiles of four recent noteworthy herbs.

Lavender
The genus Lavandula comes from Latin, lavo which means to wash. The reference is from the ancient use of lavender flowers and leaves by the Romans in bath perfumery. Lavandula belongs to the mint family (Lamiaceae / Labiatae) with about 20 species of perennials and shrubs from the Canary Islands to India with the Mediterranean region as the chief center of their natural occurrence. Besides oils obtained from some of the species for the production of perfumes, soaps, and related products, the dried flowers are also used in sachets, potpourris and cooking.

Lavenders thrive in full sun with good air circulation and not too fertile soil that's well-drained with a pH of 7. A few dwarf forms of English lavender such as L. angustifolia and L. latifolia are considered more hardy than others and only reliably hardy to Zone 6. In Minnesota L. angustifolia ‘Hidcote' and ‘Munstead' can survive some mild winters with a good layer of mulch. There is also the annual lavender ‘Lady' which can be grown from seeds. The nonhardy lavenders are best grown indoors in pots and moved outdoors for summer display.

Sage

Sage.
Photo Credit: USDA
Sage is a member of the mint family (Lamiaceae or Labiatae). The genus Salvia comes from the Latin word "salveo" which means "I save" or "I heal" because some species are reputed to have healing properties. Salvia consists of 900 species worldwide. The English word sage is from Old English "sawge" or Old French "sauge".

Medicinally sage tea has been prepared for use as a gargle for sore throats and sage leaf poultices for sprains and swellings. Sage oil reduces perspiration and was used for treating fever accompanied with sweating. In Germany an antiperspirant with sage as an ingredient is sold under the name of Salysat.

It is the garden sage or common sage, Salvia officinalis with its gray-green wooly leaves that is most known as the herb flavoring in turkey bread stuffing. This native of southern Europe, easily grown from divisions or seeds, is hardy to Zone 4. It thrives in well-drained soil and in locations with full sun or afternoon sun. The leaves dry easily. "Rubbed" sage is dried sage leaves that have been crushed. The wooly leaves don't crumble very well with the pieces clinging and held together by the wooly hairs. Try growing some of the other garden varieties of Salvia officinalis such as S. officinalis ‘aurea' (with yellow, gold leaves), S. officinalis ‘tricolor' (leaves tinted with pink, white, yellow or cream veins and edges), S. officinalis ‘purpurascens' (with purple leaves), S. officinalis ‘Berggarten' (a short, low form with larger leaves).

Echinacea

Echinacea.
Photo Credit: USDA
Echinacea or coneflower is a member of the Sunflower Family (Asteraceae or Compositae). The genus Echinacea was named for Echinus (hedgehog) due to the prickly appearance of the flower's conelike center.

For generations Echinacea plant parts were used by Native American tribes as a medicinal remedy for a number of ailments such as colds, inflammations, coughs, sore throats, and insect bites. Of the nine Echinacea species, native to North America, only three species have proven to have medicinal value. Herbal remedies have been made from aerial parts and roots of Echinacea angustifolia and Echinacea pallida and roots of Echinacea purpurea. It is the latter that is frequently used in present day herbal remedies. Echinacea has shown to have the ability to work with the body's immune system and helps to resist the onset of diseases. Remedies are available for over the counter sales as herbal supplements in the form of tablets, tinctures, and tea.

Echinacea purpurea (purple coneflower), hardy in Zone 3, is a native of our prairies. It is an attractive garden perennial, that grows well in full sun or partial shade and in rich, well-drained soil. It blooms from July to September and is not too demanding with its cultural requirments. Propagation is best by divisions or seeds. It has a tendency to self sow in the garden. The native purple coneflower grows to 3 - 4 feet and has drooping purple-pink petals. In recent years other cultivars of the purple coneflower have become available at nurseries and garden centers. Cultivars such as Echinacea purpurea ‘Magnus', a 1998 Perennial Plant of the Year, with deep pink petals that point out rather than down, and Echinacea purpurea ‘White Swan' with white flowers, do well in Minnesota gardens with little care.

Basil

Basil.
Photo Credit: USDA
Basil, an aromatic herb, an important ingredient in international cuisines, belongs to the genus Ocimum in the mint family (Lamiaceae or Labiatae). It consists of 64 species native to tropical areas of Asia and Africa. The genus Ocimum is derived from the Greek work okimon for smell and was used by Theophrastus for the herb basil. Both the words basilisk (king of serpents) and basil (royal herb) are from the Greek word basileus to mean king. In ancient times the basilisk was a mythical lizard-like monster that could kill with its breath and glance. This connection of the 2 words has left basil with the symbolic meaning of hatred, hostility, and insanity and association with dragons, salamanders, and scorpions.

Ocimum varieties and cultivars vary greatly not only in their physical and aromatic properties, but also in their uses in cooking and medicinal applications. When used correctly, basil essential oils can help with sinus congestion. Rubbing bruised basil leaves on insect bites can ease itching. In recent years research has been concentrated in basil breeding for increased production of essential oils for perfumery and aromatherapy needs as well as for ornamental plants for landscaping.

Basil is a warm season herb that's easy to grow. It's an annual for gardeners in northern climates. The seeds germinate quickly in about 3-5 days in warm soil. Within hours of sowing and upon contact with moist soil, a mucilaginous coat surrounds the seeds. If you see that, don't worry. There's nothing wrong with your seeds. It's just a characteristic property of the seeds. Basil seeds like warm soil to germinate in so it's best to start seedlings indoors and have transplants ready for the outdoors when chance of frost is past. Basil grows well in containers or in the ground with full sun and well-drained soil that's kept moist. The plants thrive in hot, humid weather and are not tolerant of cold temperatures.

Harvesting basil throughout the growing season makes the plant even more productive especially if you remove the flowering stalks. Basil can be used fresh, dried, frozen, infused in oil or vinegar, or made into pesto. Pesto is the Italian word for "ground" and is a mixture of basil leaves, olive oil, garlic, parmesan cheese, and pine nuts. Pistou is the French equivalent of pesto, but is not as thick. Pistou is derived from the French Provencal dialect (from Nice) for "pounded". Southeast Asian cuisines such as Thai and Vietnamese dishes generally use holy basil (Ocimum sanctum). Be sure to try some of the different basil available: sweet basil, ‘Genovese', lemon basil, lime basil, ‘Siam Queen' Thai basil, ‘Magical Michael', ‘Purple Ruffles', ‘Dark Opal', cinnamon basil, ‘Red Rubin', and ‘Spicy Globe'.

If you're interested in herbs, the Minnesota Herb Society maintain herb garden at the University of Minnesota Landscape Arboretum. The group meets there on the 4th Tuesday of January, March, May, August and October at 9:30 a.m. Contact Barbara Dow at dowxx004@umn.edu for information.

Herb Day: Gardening with Herbs, the 5th annual Herb Day event, will be held Saturday, June 11 from 8:30 a.m.-12:30 p.m. in the MacMillan Auditorium, Minnesota Landscape Arboretum. Topics include Annual and Perennial Herbs for Minnesota, An Herbal Picnic: Creating and Tasting plus a hands on herb planting activity. Cost is $40 for Arboretum and Mn. Herb Society members, $50 for nonmembers. Includes continental breakfast, and picnic food tastings. Call 952-443-1422 for info.

Morel Relativity
Janna Beckerman, Extension Plant Pathologist


A bowl full of
happiness-yellow morels. Photo Credit:
Janna Beckerman
If there are any positives to develop out of our statewide epidemic of Dutch elm disease, it is this: The morel hunting should be unbelievable.

It's difficult to predict where morels will grow. I have found morels in my neighbors back yard, around the grave of friend's recently deceased dog (we didn't eat those), and even under a deck after landscape tarp has been removed. I've even seen pictures of morels growing out of wet carpets in flooded basements. So, explaining where morels grow in Minnesota is difficult. To be honest, I think they grow where they want. Often times, this is in association with elm trees (and aspen, cottonwood, ash, apple…the list is very, very long). However, this association is very complex, and is referred to as mycorrhizal, and it doesn't explain why a morel would grow out of a carpet from a flooded basement.

Mycorrhizae, or 'fungus root,' refers to a symbiotic association between plants and fungi, with the fungi colonizing the plant root cortex. At this stage, the fungus exists as threads, or mycelia, that cover and/or superficially infect the surface of the plant root. This relationship between plant and fungus is characterized by the movement of plant-produced sugars to the fungus, and fungal-acquired nutrients, like phosphorus, to the plant. Almost all land plants form this association, and it acts as a bridge between the plant and the soil. However, when the plant dies, or is dying, the fungal partner begins to starve, triggering a chain reaction of biochemical events that signal the fungi to begin reproduction. Regions within the net of fungal threads begin to develop reproductive structures commonly referred to as "mushrooms."

Except morels aren't mushrooms--they belong to a distinct group of fungi known as the 'Ascomycota.' True mushrooms, like the white buttons you buy in the store and eat on your pizza, belong to the 'Basidiomycota.' Members of the 'Ascomycota' include apple scab, powdery mildew, and anthracnose, to name but a few of the other ascomycetes you curse every spring. The correct name of the reproductive structure of a morel is an 'ascocarp.' So yes, the morel is the state ascocarp of Minnesota. Based upon my experiences explaining this to others, I'd keep this information to yourself. It can be our secret.

Every mushroom edible, sometimes only once…


Lone black
morel in its natural
habitat. Photo Credit:
Janna Beckerman
Many mushroom hunters include the morel as a member of "the Foolproof Five." I beg to differ, as nothing is foolproof because fools are so ingenious. The false-morel, Gyromitra spp., gets my vote as a close look-a-like that can easily confuse excited beginners. There are some key differences that most reasonable people can distinguish between: True Morels are hollow and if you slice it open, you'll see it is filled with air (and occasionally bugs, if it hasn't been cleaned), from top to bottom. False morels are solid, and dense. Whereas true morels are made for stuffing, the same isn't true for false-morels. True morels are pitted, not wavy or brain-like compared to false morels. Finally, false morels are usually reddish-brown (in my experience). Other key differences require a microscope, but they exist. Ultimately, follow the mushroom hunters mantra "When in doubt, throw it out." False-morel poisoning can be fatal.

The sheer number of dying elms resulted in a bumper crop of morels for the last two years, and unfortunately, there is no reason to believe this year will be any different. In Minnesota, the season begins at the end of April, and ends at the end of May, or even June in the most northern regions of the state. Currently, black morels are out in the Twin Cities areas, and the yellow morels should begin to appear in the next few weeks. As long as the rainfall levels are at least normal, large harvests of morels are out there for the taking. Buon Apetito!

Dry Saute of Morels

Morels have a delicate flavor, and can be easily overwhelmed by spices. To get the most of your morels, carefully clean and debug with a minimal amount of water (all mushrooms will soak up water, and turn rubbery when cooked). Pat dry, slice. Heat butter, bacon, beef or chicken fat (1 tablespoon per half cup morels) over medium heat and add morels to form a single layer. Do not move around pan, but allow to lightly brown before flipping, and cook until the liquid has evaporated. Serve on crackers and enjoy.

There are a lot of wonderful morels recipes in "The Mushroom Lover's Mushroom Cookbook and Primer" by Amy Farges

For more information on morel hunting, biology and mushroom hunting, see:
http://www.bluewillowpages.com/mushroomexpert/morels/index.html

Please check out the diagnostics web pages at
http://www.extension.umn.edu/projects/yardandgarden/diagnostics/
May Garden Calendar
Compiled from conversations with Bob Mugaas and Nancy Rose, Regional Extension Educators

Tulips at Arboretum Photo credit:
Beth Jarvis
Lawns:
The cool weather is prime time to do spot spraying for perennial weeds like creeping Charlie, dandelions, etc. Even though the temperatures are cool, the weeds are actively growing.

Unless your entire lawn is a sea of dandelions, or other weeds, you should be able to get good results with only spot spraying. There is no point in applying herbicide over the entire lawn if it's not necessary. Broadleaf herbicides now come in ready to use mixes so they're very conveneint--no mixing or storing concentrate or a sprayer. You may need to make a second herbicide application–about 2 weeks after the first.

If you left some herbicide in a garage or other unheated building over winter, and it froze, the product may no longer be effective. Bring any of these products to your county hazardous materials drop site.

Over the next 10-14 days, you may apply pre-emergence crabgrass killers on warmer exposed sites. Cooler soils won't need to be treated quite as soon. Unless the container says otherwise, pre-emergence products should be watered in with 1/4-1/2" of water. Avoid putting them down when heavy rains threaten though a light shower is fine. Liquid herbicide applications in particular should be watered in, to wash the herbicides to the ground where they are effective.

A lawn fertilizer with a 4-0-2 ratio is recommended unless a soil test gives other results. (You'll find 12-0-6, 16-0-8, 20-0-10, etc. fertilizers in stores.) It is illegal to apply lawn fertilizers with phosphorus (the middle number in the ratio) to lawns anywhere in the state except when seeding or sodding or you have soil test indicating need.

If you plan to over-seed your lawn, be sure to power rake/vertical mow to give best soil-seed contact. Seeding is recommended for fall because weeds don't germinate then. If you dawdle with reseeding this spring, you'll be preparing the site for crabgrass, too. Remember the later you wait, the more likely the crabgrass will germinate.

If you have white/tan patches yet in your yard, they're not going to green up so you may as well repair them.

Trees:
If you're shopping for a replacement tree for one lost to Dutch elm disease or for any reason, go to http://www.cnr.umn.edu/FR/extension/ElmReplacement.html
The Sustainable Urban Landscaping Site plant selector option is also a good place to look:http://sustland.umn.edu

It's not a good time to prune trees but if you have pruning or removal in your future, now is a fine time to look for a certified arborist near you:http://www.isa-arbor.com/findArborist/findarborist.aspx

Remember to check the planting depth of any container-grown or balled and burlapped trees or shrubs that you plant. The closest lateral root should be no more than 1/4" below ground in sandy loamy soils. It can actually be a bit higher in clay soils. If the first lateral root is more deeply planted, raise the root ball and carefully remove excess soil.

Be sure to remove any rope or twine tied around tree trunks on balled and burlapped plants.

Remove trunk wrap, paper and plastic tubes from landscape trees. The plastic tube could be left on if there is ample room inside the tube for trunk expansion this summer.

If you wish to "improve" the soil in the planting hole, replace no more than 1/3 of the native soil with amendments.

Water newly planted trees and shrubs regularly so that the soil is moist but not soggy 6" deep. Trees need several years to become established.

Flowers:
Now is a great time to start new flower beds or expand older ones. You can strip sod off mechanically or kill it off with glyphosate. Using sheets of plastic or layers of newspapers takes all summer to kill the vegetation. Herbicides act more quickly in warmer weather, so you might not be able to till up completely dead grass in a week. It may take two weeks to see dead grass. You might need to make a second application of herbicide.

If you add soil to create a new garden bed, remember you must till the existing soil with the added soil, at least to a depth of 6" to create a transition layer to ensure better drainage. You simply can't dump 6-8" of soil over sod and call it a flower bed.

You can direct seed annuals that like cool weather: sweet peas, forget-me-nots, larkspur, calendulas, and bachelor buttons. Also, direct seed flowers that need to be planted directly in the garden. Seedlings that you've started indoors need to be hardened off by gradually exposing to longer periods outside. This should take a week to 10 days.

Leave tulips and other spring bulb foliage in place until it yellows and dies. The leaves produce the food to fuel next season's blooms. Don't fold or braid foliage !!!!!!!!!!!

Forced bulbs may bloom again so plant them out and let them grow. It might take a few years for them to recharge.

Fruit and Vegetables:
Cool season vegetables can be planted now. Hold off on peppers, tomatoes and eggplant, until the weather is consistently warmer. Cool weather will actually set peppers back.

Plant peas, carrots, beets, other root crops, salad greens such as lettuce and spinach plus cole crops, including Chinese cabbage and Chinese celery.

Check for asparagus beetles as asparagus spears start to emerge. http://www.extension.umn.edu/yardandgarden/ygbriefs/e251asparagusbeetles.html

Check the Home Fruit Guide for timing of insecticide and fungicide treatments for apples and other fruit plants. Avoid spraying insecticides when bees are active. The Home Fruit Spray Guide is at: http://www.extension.umn.edu/distribution/horticulture/DG0675.html

Editorial Notes

Daffodils, tulips and hosta at Arb. Photo credit:
Beth Jarvis
It's hard to get a fix on spring when it's near 70 one week then in the 30s a week or so later. There were snow flakes on my car this a.m. (May 2.)

Charlie Rohwer, a Horticulture grad student, has written an article entitled "How do those bugs eat?" It will run soon. Julie Weisenhorn who teaches one of the Horticulture Department's landscape design classes will provide us with a step by step report on the latest addition to the teaching garden. She'll cover from concept to installation.

Please feel free to cut and paste any of the articles for use in your own newsletters. All we ask is that you give our authors credit.

Back issues Yard & Garden Line News are on the Yard & Garden Line home page at www.extension.umn.edu/yardandgarden/.

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

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

If you would like to receive an e-mail reminder when the next issue of the Yard & Garden Line News is posted to the web, just send an e-mail to: listserv@lists.umn.edu (note: the second E in listserve is omitted), leave the subject line blank, then in the body of the message, type: sub yglnewslist or to unsubscribe, enter: unsub yglnewslist

Happy gardening!

Beth Jarvis
Yard & Garden Line Project Coordinator


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