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PLEASE NOTE: In the autumn of 1995, we hatched the idea for a free, local gardening publication. The following spring, we published the first issue of Michigan Gardener magazine. Advertisers, readers, and distribution sites embraced our vision. Thus began an exciting journey of helping our local gardening community grow and prosper.
After 27 years, nearly 200 issues published, and millions of copies printed, we have decided it is time to end the publication of our Print Magazine and E-Newsletter.

Can rabbit manure be used as mulch around plants?

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We have a pet house rabbit that is litter trained. Can the manure and litter (made from recycled newsprint) be used as mulch in a perennial bed or around trees and shrubs?

This sounds like a gold mine since rabbits are vegetarians. But it comes with significant cautions. Rabbit manure is higher in nitrogen than even chicken manure. It also contains phosphorus. Nitrogen is great for leaf production. The phosphorus is good for fruit and flower production. So consider exactly what you will be enhancing with its application. Average N-P-K (nitrogen-phosphorus-potassium) analysis of composted rabbit manure is 2-1-0.8, which is relatively low compared to other commercial products. In order for the manure to be useful, it must be hot composted, preferably for a year, to reduce the probability of transmitting any pathogens lurking in the litter. A hot compost pile should measure at least 150 degrees in temperature.

Composting the litter changes the material into a form plants can better use. It also allows odors to dissipate. After the year-long composting, it should be applied to the soil in late fall and worked in. Preferably, it should not be used as mulch and never uncomposted, as the high level of nitrogen can actually burn and damage plants, even with the newsprint base. Since it has to be worked into the soil to be effective, you might find this easier with your perennial bed in fall than disturbing the roots of trees and shrubs.

Related: Bunny honey – Using rabbit manure as a fertilizer

How do I remove unwanted scrub trees?

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We have scrub trees growing in our yard (around the fence line and in a crack between our patio and house). What is the best way to kill the trees and their root system without damaging our home, fence or grass?

Although a little labor intensive, the most effective way to remove scrub trees is to cut them off at ground level. Use sharp hand pruners, loppers, or small pruning saws to make a clean cut. Use bleach handwipes to clean the blades of all tools used to avoid spreading any bacteria to your desirable plants. Dry them well to prevent rust.

Next, apply an herbicide product to the cut stubs that contains the ingredient triclopyr. Use a sponge brush dipped in the product to daub directly on larger cut stubs. For pencil-width stubs, you can use a narrow-stream spray bottle. Be careful not to spray on a windy day and use cardboard shields to protect any nearby plants you want to save. Read the label directions carefully before applying, and wear protective gloves and clothing.

Video: ID and Control Unwanted Trees and Shrubs

Related: Controlling invasive star of Bethlehem

How do I get get hazelnuts to produce fruit?

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I now have 5 seedling hazelnut bushes growing, in conjunction with National Arbor Day. They are still quite small, but I would like to know if there is a special fertilizer to boost the growth of hazelnuts.

Can you spell “patience”? Nut trees or shrubs may be listed as fast growers, but it takes several years before they are mature enough to produce good edible fruit. In this case at least 6 years, maybe as long as 12 years. After that long there will only be nuts if you have a minimum of two varieties of hazelnut because, like apple trees, they are not “self-fruitful” and need a second variety nearby to achieve cross-pollination between the varieties. And then you will have to battle the wildlife that also enjoys them! There really is no magic pill fertilizer to make your hazelnut trees grow faster to the point where they produce those wonderful fruits more quickly. Instead, make sure you get a soil test for the area in which they are planted to know the pH and the nutrient level of the site. Hazelnut trees (Corylus avellana, C. americana, C. colurna ) like a pH of 6 to 7. Although they will grow and produce fruit in shallow soils, they prefer a well-drained site with plenty of organic matter. Sandy and clay soils both benefit from cultivating in composted organic amendments.

Hazelnuts were often established as hedgerows in Europe and Australia since the plant’s natural characteristic is shrubby as opposed to single stem. Often for nut production, they are kept pruned to a single trunk and can produce a deep taproot. Although they do produce many shallow surface feeder roots, they prefer not to be moved once planted. Hazelnuts also don’t mind the cold winter temperatures of Michigan. They actually need a chilling of a couple months in the low 30’s to help them toward fruit production. However, they really do not care for drying winds. So while they are still young and easily moved, make sure you have sited them properly.

Related: Growing Fruit in Michigan

Related: Opportunities in forestry – Hazelnuts

What is a good choice for a privacy shrub?

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What is a good choice for a privacy shrub in southwestern Michigan? How early in the spring can I plant it?

When seeking privacy, plant more than one plant. A trio works well as they balance each other, forming a community rather than an “orphan” look. Plant three of one species laid out in a shallow triangle so they fill in around each other aesthetically. Straight rows look artificial. You can also vary the trio with a single specimen for the center point and flank each side with another species. 

For example, center a leatherleaf viburnum (Viburnum rhytidophyllum)with its soft, oval, gray-green leaves and flank it with native ninebarks (Physocarpus opulifolius) with burgundy leaves and peeling bark. Both are deciduous in zone 5. Viburnum tops out at about 10 feet and the ninebark tops out about 8 feet. They both bloom spring to early summer, have considerable winter interest, grow relatively quickly, and deer don’t find them appealing. 

Another possibility is centering an evergreen such as ‘Green Giant’ arborvitae, which is an open pyramidal evergreen and less appealing to deer. They are tolerant of various soil types, but prefer good drainage. An evergreen paired with deciduous shrubs can get you more “instant” privacy than waiting for three identical shrubs to reach maturity. 

Flank the evergreen with the ninebark variety Amber Jubilee which has gold-orange overtones in the leaf veins, or ‘Summer Wine,’ which features a dark burgundy color. By creating a group of compatible plants, spaced apart according to their mature width, you have something attractive to look at while achieving a privacy screen.

Related: Step-by-step guide to planting trees and shrubs

Related: Tree and shrub pruning tips

Mountain pine beetle quarantine enacted in Michigan

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Damage caused by the Mountain Pine Beetle in British Columbia, Canada. (Photo: Jonhall / Wikipedia)
Damage caused by the Mountain Pine Beetle in British Columbia, Canada. (Photo: Jonhall / Wikipedia)

The Michigan Department of Agriculture and Rural Development (MDARD) is working to protect Michigan’s pine trees from a potentially devastating pest: the mountain pine beetle. One of the most destructive forest pests in North America, it is known for outbreaks that have killed millions of pine trees in the western United States and Canada.

According to MDARD Director Gary McDowell, “Mountain pine beetle hasn’t been detected in Michigan yet, but we’re taking the necessary, proactive steps to ensure our pine resources are here for generations to come,” said McDowell. The state’s new “Mountain Pine Beetle Exterior State Quarantine” regulates the movement of pine forest products with bark including logs, stumps, branches, lumber and firewood originating from a number of impacted western states.

The beetles affect pine trees by laying eggs under the bark and introducing a blue stain fungus. The joint action of larval feeding and fungal colonization kills the host tree within a few weeks of successful attack. As beetle populations increase, or as more trees become stressed because of drought or other causes, the beetle population may quickly increase and spread.

Mountain pine beetle has expanded its range, moving northward and eastward. The expansion is attributed to warmer winters, which allow more beetles to survive. Michigan’s pine resources are at risk of attack, including white pine, jack pine, red pine, Austrian pine, and Scots pine. Learn more about the quarantine here. 

What is causing fruit to drop early on my apple tree?

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McIntosh apples on a tree. Photo: George Chernilevsky / Wikimedia Commons

We have a McIntosh apple tree that is about 30 years old. We have never sprayed it. In the spring, lots of tiny, green apples start falling. The remaining apples are wormy and misshapen, thus we end up composting all of them. Is there anything we can do so the apples are good to eat?

Every McIntosh apple has a direct lineage to a single tree discovered in 1811 by John McIntosh in Dundas County, Ontario. Your 30-year-old McIntosh is a venerable species worthy of treatment.

Premature apple drop can stem from several factors. A tree unable to support the vast number of fruits it has produced naturally thins out the fruit to decrease competition and conserve energy. Environmental conditions such as later frosts, excessive heat and cold, and abrupt changes in humidity can cause fruit to drop. The soil may be nutrient-deficient to support fruit growth. A soil test targeting apple trees is in order. Irregular watering can also cause fruit drop. Examine the weather patterns of the last few years to determine what weather conditions occurred. Consider your watering practices and note changes and improvements.

The condition of your remaining apples suggests a strong pathological source. If there are “worms” in the fruit, you probably have codling moth (Cydia pomonella). The worms are the larval stage of this pest. The second generation adults emerge in July laying eggs on the apples. The young caterpillars can tunnel into the developing fruit shortly after egg hatch, exiting to pupate into another generation moth. This is when the most damage is done.

To get good eating apples again, you need a steady maintenance program of vigilance and treatment. Homeowners can manage watering and fertilizing consistently. You can also practice good yard hygiene by removing fallen leaves, fruit, and debris from the tree’s vicinity. Such plant debris provides opportunities for re-infestation. Through observation in the spring, verify the codling moth is the culprit before embarking on any spray insecticide program. Because of the critical timing of sprays and the chemistry of insecticides, hiring a professional arborist who is experienced in tree fruit culture is a wise move. In the space of one season, you should see a marked improvement in edible fruit.

ALSO READ: Tips for Growing Apples in Michigan

New invasive plant found in Calhoun County

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invasive plant mile-a-minute weed
Mile-a-minute weed (Photo courtesy: Flickr/natureserve)

Although it doesn’t spread as fast as its name suggests, invasive plant mile-a-minute weed has made its way to Michigan. This fast-growing, invasive vine recently was verified at the Whitehouse Nature Center at Albion College in Calhoun County. The plant is native to India, Asia and the Philippine Islands, and can cause harm to Christmas tree farms, reforestation projects and restoration areas by smothering young plants and trees under its dense growth.

Mile-a-minute weed is identified by its triangular leaves, spikes of pea-sized blue fruits, and recurved barbs lining the stems and leaf margins. Unusual circular leaves called ocreae clasp the stem beneath each fruit spike.

It can grow up to 25 feet in six to eight weeks. Dense, prickly thickets overtake native vegetation. Seeds may survive in the soil for up to six years.

Each fruit contains a single seed, and vines can produce up to 3,500 seeds per year. Fruits are eaten by birds, deer and small mammals, which can spread seeds miles away from the original plant.

Learn more here.

Related: Janet’s Journal – Celebrate and respect the diversity of native plants

How do I overwinter small potted evergreens?

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Can I overwinter boxwoods in plastic pots (about 5-gallon size)? I’m not sure what variety they are. Or should I plant them in the ground even though it is November?

Any small ornamental evergreen or conifer in a container needs special treatment to overwinter a zone 5 winter (-20 degrees). If you have the space, you can bury the entire container in the ground and mulch leaves and compost over the base to protect it from freeze and thaw. If the location is subject to winds, a wind barrier of burlap or fabric to protect the leaves and needles is essential to avoid desiccation. You can also surround them with a staked chicken wire cage and fill the space with fall leaves. This also protects against sunscald. If no ground space is available, then place the boxwood containers in a sheltered area, cluster them together for protection, and place a windbreak around them for added protection from desiccation. Once the soil is frozen, the shrubs can’t take up moisture through their root systems to replenish what is lost in their leaves. You can also use an anti-desiccant spray on the foliage to further prevent moisture loss.

Once ground soil shows signs of thawing, night temperatures remain above freezing, and you see signs of spring growth on other plants, then you can remove the heavy winter protection. Give them a few weeks to acclimate and day temperatures to warm before moving them from their sheltered location.

Related: Overwintering Sweet Potato Tubers

Try some forest bathing this fall

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The practice of forest bathing began in the 1980s but humanity’s need to be in and part of nature is far older.

Being in nature is something that comes naturally to humans. Forest bathing, or shinrin-yoku, is a form of nature therapy that originated in Japan and has seen renewed interest in the past few years. While the practice began in the 1980s, humanity’s need to be in and part of nature is far older. It’s an integral part of our species’ history, something rooted deep within each of us.

Nature can be a healing force. For centuries, we’ve recognized the powerful effect of reconnecting with the natural world. There is something rejuvenating about being out among the trees, in being surrounded by the sounds of the forest, the scent of wildflowers, the way sunlight plays through the leaves. Finding that revitalization is one of the key tenets of this practice.

“The art of forest bathing is the art of connecting with nature through our senses,” wrote Dr. Qing Li, the world’s foremost expert in forest medicine, in his book Forest Bathing: How Trees Can Help You Find Health and Happiness. In his book, Li explores the science and history behind forest bathing and how best to practice it. “The key to unlocking the power of the forest is in the five senses,” he wrote. “Let nature enter through your ears, eyes, nose, mouth, hands and feet.”

According to Li, there is no one way to forest bathe; many activities can achieve the intent of the practice. Yoga, foraging, tai chi, plant observations, and even just walking out in the woods all can be considered part of forest bathing.

Related: Oaks, the king of trees

Replacement options for a dying ash tree

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Ginkgos in the fall can be spectacular, the fan-shaped leaves glowing gold. Sometimes the color is a less showy yellow-green, but whatever the fall color, the leaves drop quickly soon after and all at once, a leaf raker’s dream.

Part 2 of 2 – Trees for root spaces greater than 10 feet wide

When an ash tree is the friendly cover above your patio or picnic table, and it is doomed to fall to the plague of emerald ash borer, its loss is a personal one. Here’s some consolation: in that location, with park-like room for roots to spread, many species can be expected to grow well and quickly.

Choose from this list and score one for diversity. By planting one of these excellent but underused species, you’ll help diminish the chance of whole-neighborhood defoliation during some future insect or disease attack. 

Trees for root spaces at least 10 feet wide

These trees need larger boulevards and islands, where roots have at least 10 feet to spread in all directions:

Ginkgo (Ginkgo biloba, fruitless male varieties such as ‘Autumn Gold’ and ‘Santa Cruz’) 50 to 80’ tall with a variable spread (‘Santa Cruz’ is very wide, ‘Autumn Gold’ just a bit more than half as wide as tall). Grows 12” or more per year in its youth, slower as it matures. Flowers are inconspicuous. Fall color can be a superb gold. Female trees are not desirable as the fallen fruit is malodorous. Full sun. Prefers deep, moist, sandy soil but will tolerate almost any situation.

Hackberry (Celtis occidentalis) 40 to 60’ tall and wide, may be larger. Grows 1 to 2’ per year. Grows in almost any soil and moisture condition, in full sun. Makes no show of flower or fall color. Hard-seeded, berry-like fruit loved by birds and small mammals. This is another of many native trees that are just being discovered for use in the landscape. Like the ash, it’s a tree that rarely stars, yet always fills a supporting role. Some selections have been made, such as ‘Prairie Pride’ with especially lustrous leaves and a broad crown or ‘Windy City’ for a fast growth rate and especially wide spread reminiscent of its relative, the American elm.

Hardy rubber tree (Eucommia ulmoides) 40 to 60’ tall and wide. Grows 12 to 18” per year. Lustrous dark green foliage that’s pest free (and so it’s wonderful to sit under!). Inconspicuous bloom. No fall color. Full sun and almost any type and condition of soil. This tree fits the bill for people who want a non-fussy, relatively fast-growing, pest-free shade tree that does not drop fruit or seeds.

Turkish filbert (Corylus colurna) 40 to 50’ tall and about half as wide. Grows 12-18” per year. Nothing worth seeing in its tiny flowers or fall color. Nuts ripen in fall. Dark green foliage is pest free. In full sun and well-drained soil can tolerate almost any other adverse condition, including the droughty soils that cause scorch on maples.

Yellowwood is a little known native that’s nearly pest free, a true showstopper in bloom or fall color, and excellent for shade on small properties by virtue of its wide spread.

Yellowwood (Cladrastis kentukea) 30 to 50’ tall. Wider than tall. Grows about 12” per year. Fragrant white flowers in large pendant clusters in June. Smooth gray bark. Full sun and well-drained soil.

Trees that should not have any restriction to their roots

These are trees that belong in back yards, parks and wide open spaces.

Bald cypress strikes many people as an evergreen, then surprises them in fall by dropping its needles.

American linden (Tilia americana) 60 to 80’ tall and 2/3 as wide. Grows 12 to 18” per year. Small white flowers in June are fragrant enough to carry across a yard and very attractive to bees—thus this is called “bee tree.” Fall color sometimes yellow. Full sun to half sun. Almost any soil.

LEFT: American linden is a stately, dependable shade tree—pyramidal in its youth, showy in bloom, and comfortably rounded in old age. RIGHT: Bur oak has no showy flowers and its fall color is dull yellow. But it is rich in character with deeply ridged, corky bark—an outline to admire while you lie in its shade.

Bald cypress (Taxodium distichum) 50 to 70’ tall and half as wide. Pyramidal. Grows 1 to 2’ per year. Fern-like foliage emerges yellow green and fades to yellow or orange-brown before dropping in fall. Shaggy red-brown bark and buttressed trunk base are attractive. Full sun. Moist to wet soil.

Black gum is all you could want in a shade tree—high branched, not messy, and great fall color. However, it is not tolerant of compacted, dry or highly alkaline soils, so plant it to replace a back yard tree, not one by the street or sidewalk!

Black gum (Nyssa sylvatica) 30 to 50’ tall and 2/3 as wide. Grows 12” per year. Its bloom is inconspicuous but fall color is stupendous, from yellow orange to deepest scarlet. Small fruits ripen in early fall and are eaten by birds. Full sun or part shade. Deep, moist, well-drained soil. Don’t site it in harsh winds.

Bur oak (Quercus macrocarpa) 70 to 80’ tall and wide. Can be larger. 8 to 12” growth per year. Nothing to note in terms of flower or fall color. Full sun. Most any soil. More tolerant of city conditions than almost any other oak.

Dawn redwood (Metasequoia glyptostroboides) 70 to 100’ tall, 25’ wide. The tree is an impressive pyramidal form. Grows 3’ a year. Inconspicuous flower. Foliage is ferny, very attractive and sometimes red-orange in fall. Bark is shaggy red-brown, easy to like. Full sun. Prefers moist, well-drained soil but is very tolerant of wet soil. Pest problems are very rare.

LEFT: Dawn redwood may keep its lowest branches into old age and sweep the ground, or branches can be pruned to accommodate traffic. The author was not a believer until she saw dawn redwood as a magnificent street tree in Manhattan. RIGHT: Kentucky coffeetree in winter is a stately form indeed.

Kentucky coffeetree (Gymnocladus dioicus) 60 to 75’ tall, not as wide as tall. Can be larger. Grows about 12” per year. Flower is insignificant. Female trees can bear large, hard pods; if this is unacceptable, hold out for the male variety ‘Prairie Titan’ or ‘Stately Manor.’ Fall color may be a good yellow. It can aggravate fastidious rakers since in the fall the leaves, the ribs that connect the leaflets, and the seed pods drop at different times. Full sun. Deep, moist soils are best, but the tree will tolerate almost any city condition. This tree got its name when early American settlers used the seeds as a coffee substitute, but we are now told its seeds are toxic.

Lacebark elm is a dependable, fast-growing, wide-spreading shade tree with gorgeous bark. It has an additional common name, Chinese elm, that causes some people to confuse it with an inferior tree, Siberian elm.

Lacebark elm (Ulmus parvifolia) 40 to 50’ tall and wide. Grows 1 to 2’ per year. Inconspicuous flower. Fall color may be yellow or red-purple. Mottled, peeling bark is a plus in winter. Full sun. Moist, well-drained soil is best but it tolerates many soil conditions.

Swamp white oaks are faster-growing than most people realize, so we can enjoy them in their youth as well as leave them to our grandchildren.

Sawtooth oak (Quercus acutissima) 40 to 60’ tall and wide. Grows 2’ per year during its first twenty years. Golden catkin flowers in spring can be attractive. Foliage is very clean, deep green in summer, often a good yellow in fall. Acorns drop early in fall. An impressive, high-branched shade tree. Full sun. Well-drained soil.

Shingle oaks can frustrate some gardeners by holding onto leaves through winter. Others see the leaves as winter interest. Isn’t diversity grand!

Shingle oak (Quercus imbricaria) 50 to 60’ tall and wide. Can be larger. Grows 12 to 18” per year. Leaves unfurl red, are lustrous dark green in summer and become yellow to red-brown in fall. Full sun. Moist, well-drained soil.

Swamp white oak (Quercus bicolor) 50 to 60’ tall and wide. Can be larger. Grows about 12″ per year. With age, develops an impressive, stout trunk and deeply furrowed bark. Fall color can range from yellow to maroon. Full sun. Moist to wet soil.

Read More: Part 1 – Trees for root spaces less than 10 feet wide

Article by Janet Macunovich and photos by Steven Nikkila, www.gardenatoz.com.

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