Archive for the Ask MG department

Why doesn’t our garden have earthworms in the soil?

February 11, 2022 • Leave a Comment

Our several-year-old vegetable garden is high in organic matter but has no earthworms — none at all. What are possible reasons and potential solutions? If the soil is not healthy for worms, is it lacking something important? Our lawn adjacent to the garden has plenty of worms.

A productive garden thoroughly depletes the organic matter to produce those prize-winning squash and tomatoes. So we correctly add organic matter annually. The problem may lie in the method.

There are also different kinds of earthworms. Some live closer to the surface as evidenced by those living in your lawn. Epigeic species live in or near the surfaceplant litter. They are typically small and are highly adaptable to variable water and temperature conditions associated with lawn culture. Endogeic species are more mobile, making temporary tunnels, and live in the upper soil layers feeding on soil and organic matter. Then there are the deep-burrowing anecic species, which we often call “nightcrawlers.”These guys drag surface litter down into their burrows which can be several feet down below the soil surface.

The nightcrawlers are much more common in the north and east where there are clay and loam soils. Something that gardeners do not realize is that continuous tillage or disturbance of the soil will cause most earthworms to vacate the premises. Remember your lawn soil is rarely disturbed. If you mechanically rototill organic matter into your garden every year or vigorously deep dig your soil before planting, you may be chasing the worms away. They don’t get the chance to do their job. You keep destroying their optimum working conditions.

Examine your garden prep and add compost into the top 6 inches instead of deep tilling. The vegetables will still take all that they need. Cultivate it in by hand rather than mechanical means. Continue to practice good crop rotation.

How do I care for my damaged kousa dogwood tree?

January 28, 2022 • Leave a Comment

I planted a kousa dogwood last summer, and it looked to be doing well, with nice autumn foliage. Last fall it looks as if a fat raccoon has tried to sit in the fork, and two of the largest boughs have been torn off. The damaged dogwood height is about 5 feet, the largest branch left is 3/4-inch diameter, and there is a huge scar where a branch got torn off. What should I do this spring to the wound?

Do not paint or bandage the wound left by the torn branch. This only provides hiding places for insect pests and traps moisture which can lead to mold issues. Trees have an amazing ability to heal over injuries. When the wound occurred, the cambium reacted chemically to seal off that area to prevent moisture loss. Eventually an exterior bark layer will form over that spot, much like a person’s skin heals from a cut.

Make sure the dogwood is sited for optimum light and water preferences. Water the roots deeply when day temperatures are high and rainfall is absent. The tree has endured stress with this injury and used additional resources to repair itself. You can apply a granular tree and shrub fertilizer around the root zone before mulching to help the plant rebuild its energies.

Provide two inches of composted mulch over the root zone, avoiding contact with the tree trunk. Watch the tree’s growth during the season. You may notice stunted leaf and branch development and even lack of bloom buds on the side of the tree with the wound. To prevent inquisitive critters from chewing on the bark, place a narrow cage of wire mesh around the trunk from the ground to about 2 feet up, being careful not to wrap the trunk with wire.

After spring bloom, you may prune the dogwood to re-establish shape and form. In early fall, you can apply another light dose of granular fertilizer per the container label to help the tree’s nutrient storage for winter.

Elsewhere: Flowering Dogwood Problems

Will adding mulch increase the soil depth of a bed?

January 25, 2022 • Leave a Comment

If I keep adding mulch to my garden beds, will it not eventually increase the soil depth in that bed? And if it does, what happens to all the surface roots if I remove the mulch (soil)?

Adding about 2 inches of mulch to our garden beds prevents moisture loss, improves the soil condition, and prevents weeds from germinating. Natural wood mulch, composed of fine wood chips, ground up leaves and twigs, encourages worms and microorganisms to break down the material into nutrients which plants can absorb through their roots. This relationship between the soil organisms, decomposing organic material and plants creates a self-sufficient ecosystem if we, as the caregivers, don’t ruin it.

When you clean your garden beds in spring, lightly cultivate the surface material into the soil bed. How much light and water a particular bed gets can speed up or slow down the composting of the mulch. Some beds may need an inch of new mulch each year around mid-June or when temperatures heat up. Other beds may be slower and may only need additional material every other year. Application is not an auto-pilot garden chore.

Do not apply more than what is recommended. More is not better for preventing moisture loss or weeds. Thriving plants have deep roots in the soil rather than roots close to the surface. Overloading on mulch gives the plant a false sense of where the real soil is and can keep the hair-like roots away from microorganism activity.

Can I use a rusting antique urn for planting?

January 12, 2022 • Leave a Comment

I have an antique iron urn that is sitting outside and has begun to rust. Is there any danger to plants if I use it for a container/planter? Does it matter if I use annuals or perennials? I am also considering planting a yucca in it; how do you think it would do?

Your container will work well with no adverse reactions to rust by your plants. However you must drill several large holes in the bottom of the container to allow for drainage. To stop the soil from plugging the holes and restricting drainage, put a piece of screen or weed cloth over the holes. You may have a problem with the existing rust on the bottom—if you place your container on concrete or wood, the rust and water that drains out may stain the surface below. Annuals are always a good choice for planters; they do well in the summer and are not a concern when it comes time to put things away for the winter. Perennials (or the yucca) will require protection from the winter elements (such as putting the container in the garage). The same would be true for an evergreen or shrub. Perennials will also require repotting and division due to the restricted environment in the metal urn.

How do I overwinter cannas?

November 1, 2021 • Leave a Comment

Canna lilies are vigorous growers, spreading and creating large clumps of fleshy rhizomes that can be dug, lifted, and stored over the winter so they may be planted again next season. (Eric Hofley / *Michigan Gardener*)

I have been unsuccessful in overwintering cannas; they get mushy or just don’t survive. What’s the trick?

Canna lilies are vigorous growers, spreading and creating large clumps of fleshy rhizomes. Whether in the ground or container, their vibrant colors and reblooming ability make them desirable additions to a garden. Keeping our favorites from year to year is also cost effective.

Using a fork, gently lift the shallow-rooted clumps from the soil and lay them out on trays with newspaper. Separate the rhizomes with your hands, being careful but not paranoid if some of them break. Sort and trim out any damaged rhizomes. If they have been in ground or container soil, do not wash them off. Let the soil dry naturally and brush it off later. If they have been in a pond situation, then clean that debris off. Let them dry for a couple days.

Trim the stalks to about two inches above the rhizomes with a clean knife or pruners. Remember all naked rhizomes look identical. To keep varieties identified, put a label with each group and keep them separate. Once dry, wrap them in dry newspaper or paper lunch bags, and place in open cardboard boxes. Shoeboxes are great for large numbers of multiple varieties.

The key is keeping them dry and cool while you wait to replant them. Cool, dry basements and fruit cellars that don’t freeze are ideal. Do not place near furnace vents where heat can make them sprout prematurely. Check once or twice over winter for soft or shriveled rhizomes and discard. If more than a few are rotting, then move them to a drier location.

Related: Planting cannas in containers

How long to vegetable seeds remain viable?

March 16, 2021 • Leave a Comment

How long can vegetable seeds be kept? A year ago I purchased many vegetable seeds in hopes of starting a garden last spring. My plans were interrupted and now the garden is scheduled for this spring. The seeds are all dated 2011 and have been kept in their original packaging and stored in my basement. Will these seeds still be viable this spring?

Properly stored seed remains viable for different lengths of time depending on the type of seed. Be aware that seed companies may store seeds up to the number of years of their viability prior to selling them. If you purchased your seed from a reputable catalog or nursery, you can call them to find out what their company protocol is.

Since all your seed was purchased in 2011 and dated as such, you have a fair chance that the unopened packages will be viable. Most vegetable seeds are good for two years with some, like lettuce, viable up to six years. If they have been kept dry and cool in your basement, those conditions simulate dormancy.

To test for germination, sprout seeds between moist paper towels; if germination is low, either discard the seed or plant enough extra to give the desired number of plants. You will know quickly which seeds need to be repurchased.

Can rabbit manure be used as mulch around plants?

March 11, 2021 • Leave a Comment

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.

How do I remove unwanted scrub trees?

March 1, 2021 • Leave a Comment

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

How do I get get hazelnuts to produce fruit?

February 13, 2021 • Leave a Comment

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

What is a good choice for a privacy shrub?

February 8, 2021 • Leave a Comment

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: Tree and shrub pruning tips

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