Plant oats as a garden cover crop

September 24th, 2015

It’s not your imagination, the growing season is winding down early this year. The excessive rain and cooler than normal temperatures in our area have combined to make it a challenging season for many garden plants especially the warm weather crops like tomatoes or peppers.

Farmers are noticing it too. Many field crops never fully recovered from poor start of the season and are showing signs of maturing early. As a result there may be a reduction in yields as well.

Certain beds in my garden are already kaput. But there is a silver lining in that. It gives me a chance to plant a green manure crop, which I don’t often get to do.

The terms green manure and cover crop are basically synonymous. Green manure is a crop that will be turned over into the soil while still growing, a cover crop may or may not be turned into the soil right away.

These types of crops are great for recovering soil nutrients from the soil and holding them until next year’s planting season. Some soil nutrients such as nitrogen are easily washed down into the soil profile by fall rains or melting snow putting them out of reach of most garden plants. Much of that valuable garden nutrients that you worked so hard to build up could be lost.

Multiply the nutrients over hundreds of acres and you can see why farmers use cover crops to save money and protect the environment at the same time. Nutrients that stay in the field will not get washed into steams and rivers where they end up being a source of water pollution.

In other words, green manures effectively “mop up” nutrients and hold them in place until they are needed next year.

In a garden situation, the biomass that a green manure crop adds to the soil may be more valuable than the nutrients they conserve. You really can’t have too much organic material in garden soil.

A cover crop also provides a better habitat for soil microbes to flourish as opposed to bare soil.

Planting cover crops is a fairly advanced technique for home gardeners even though it is very effective for both vegetable and flower gardens.

If this is your first time planting cover crops, consider oats, yes the same plant that is harvested and used for making your breakfast cereal. They make a very effective cover crop.

This time of the years we are looking for a plant that will make quick growth and oats fit the bill. Even though they grow quickly, they should be planted very soon.

The other big advantage that oats have is that they will die over winter leaving a mulch on the soil surface that can be tilled in next spring. That also eliminates the possibility that they may become a weed in your garden. I’ve had winter wheat come up in the spring — seeds from straw mulch — and before I knew it they became a problem. Have you ever tried to pull up a well established clump of wheat? They’re pretty tough plants.

Planting oats is much like planting grass seed except the seed is much larger.


Oats ready for planting. Note that they still have their outer covering, the hull surrounding the seed

Oats ready for planting. Note that they still have their outer covering, the hull, surrounding the seed

Sow oats at a rate of two or three pounds per 1000 square feet about an inch deep. Farmers use an implement called a seed drill to plant oats. The easiest method for a gardener is to broadcast the seed by hand, then till very shallowly with a tiller. Finish off by lightly pressing the area down so the seeds make good contact with the soil.

Farm supply stores sell oat seed however you may have to go online to buy small quantities.


Flowers on elephant ears — colocasia

September 24th, 2015

I’ve been growing Elephant ears — Colocasia esculenta — for many years. Over that period of time I’ve rarely had them bloom. They just don’t set flowers very often.

Normally when plants blossom, it means they are all set to produce seeds. Colocasia, however has been cultivated for so long, that it no longer is able to produce seeds and relies on people to reproduce. In tropical regions, people plant the underground corms like we would plant a flower bulb here in Michigan.

Colocasia is a dramatic addition to the landscape with it’s huge leaves that easily grow to three feet long in Michigan. In it’s native area in the tropics the leaves can measure six feet in length.

People in the tropics don’t grow them for their landscape, instead they eat them. There, colocasia is called taro and is a major food crop where it is used like we use potatoes here. Millions of tons of taro are harvested each year.

One winter, many years ago, I had a recent immigrant from the south Pacific visit the greenhouse where I was growing dozens of colocasia in pots getting them ready for planting out into the landscape. She recognized them immediately and asked me if I was growing them for harvest. I told her they were for planing out in the landscape as a decorative plant. She laughed and thought that was quite funny!


The flower bud on my colocasia is ready to open.

The flower bud on my colocasia is ready to open.

My blooming colocasia was one that I stored in my semi-heated garage over winter. I kept it in its pot and let the soil dry out. I watered it once in a while.

The plant went dormant and was exposed to some cool temperatures for extended periods of time but it never got much colder than the lower 40’s. The only light it got was low, indirect sunlight from a small garage window.

I have a theory that stressing the plant somehow triggered a flowering mechanism. The other colocasia I had bloom was about 12 years ago and that plant was stored over winter much the same way.

I’d be interested to hear if any readers have had similar experiences with their colocasia.


Medicinal garden growing at Matthaei Botanical Gardens in Ann Arbor

September 10th, 2015

Not long ago growing culinary herbs in a home garden was regarded as an eccentric thing to do and only the most adventuresome gardeners grew medicinal herbs. Things have changed and more gardeners than ever are growing herbs of all kinds.

Seeds for medicinal herbs are readily available in catalogs and online stores making it easy to get started with medicinal herbs.

There are plenty of books and online resources available for anyone interested in growing medicinal herbs but nothing can replace seeing it first hand.

For a wonderful introduction to the world of medicinal herbs visit the Medicinal Garden at University of Michigan Matthaei Botanical Gardens. The folks at Matthaei have collaborated with the U of M College of Pharmacy to develop this garden. There you can see many different medicinal plants growing.

Over forty percent of medicines are derived from plants.

Over forty percent of medicines are derived from plants.

The garden is not organized by genus and species as botanists like to do but rather by human body systems: respiratory, gastrointestinal, cardiovascular and more.  Other areas of the garden are devoted to disorders such as diabetes, infectious diseases, cancer, etc.

Matthaei Botanical Gardens is located near Ann Arbor at 1800 North Dixboro Road, a half mile or so south of Plymouth Road. They’re open daily from 10 am to 8 pm during the summer season.



Mud dauber wasps are busy

September 3rd, 2015

This week while going through some items in a storage shed, I came across a beautiful dried ball of mud inside an antique trunk. It was the nest of a wasp known as a mud dauber.

When we think of wasp nests, usually the first thing that comes to mind is the papery nest of the paper wasp or the football-shaped nest of hornets. Mud daubers build their nests out of mud. There is plenty of mud for the wasps this summer because of the regular rains we’ve been having.

Mud daubers are not social insects like paper wasps and the others. Instead, they spend their lives as single, solitary insects. They do everything by themselves including, building a nest, laying eggs and collecting food for their young.

There are many different species of mud daubers in Michigan, this one is called the “black and yellow mud dauber”.

The adults look similar to the more common social wasps but are larger and have exaggerated features like the thread-like connection between their abdomen and thorax.

The female mud dauber builds the nest by collecting mud along the edge of puddles. Using her mouth parts, she rolls the mud into a ball then lifts it into the air and carries it to the nesting site. There she adds the mud to her nest, building rooms or cells for her young. Each cell is big enough for one young mud dauber.

The entrance to the nest is sealed shut. She must be out working collecting mud or food for her young.

Here she is, busy plastering new mud on her nest.


The entrance to the nest is open, she must be nearby.


While the female is away from the nest gathering mud or foraging for food, she temporarily closes the entrance to her nest to keep predators away from her young. During that time, the daubers are in the larval stage of their life cycle.

The female also packs away food for the developing larvae by placing insects or spiders into each cell so the larva has enough food in its cell to carry it through its growing stage. Some types of mud daubers only prey on spiders while others prefer caterpillars or other insects.

The entrance to the nest is closed shut. Mama mud dauber must be out collecting more mud or insects for her young.

The entrance to the nest is closed shut. Mama mud dauber must be out collecting more mud or insects for her young.

The prey is only for the young though. The adults feed on nectar, honeydew from aphids or other sugary liquids. Sometimes you can spot them sipping sugar water from hummingbird feeders.

Unlike other wasps and hornets, mud daubers don’t defend their nests. They are not aggressive and rarely sting. Although if you try hard enough you can sometimes provoke one into stinging you.

According to one university website, some species “sing” while building their nest! Mine didn’t seem to be in a singing mood when I found her.

They are generally considered beneficial insects because they eat other insects. You could argue that the spider-eaters are not very beneficial because spiders eat insects too — that is unless you hate spiders.

Most of the time we don’t notice the daubers until they build a nest somewhere where we don’t want it. Some people destroy the nest as soon as they find them.

There seems to be a small industry built around exterminating mud daubers and getting rid of their nests. I prefer to let leave them alone and let them go about their business.

I’ve noticed other smaller species of mud dauber wasp around too. They are not shy and can be very annoying as they buzz around looking for small holes to use for building their nests.


Silky dogwood

August 20th, 2015

One of my earliest childhood memories in the garden is discovering a shrub  tucked away in a out of the way corner of my grandmother’s  garden. The shrub had the most striking metallic-blue berries I had ever seen. Years later I found out it was a silky dogwood.

Now decades later, I found another silky dogwood growing on our property which, by the way, is only a mile or so away from my grandparents old farm. It is a wild plant that came up in the area that we use for the chicken exercise area. It was carved out of a part of our yard that we left as a natural area to attract wildlife.

The memories came flooding back to me when I saw the familiar cool-blue berries. This is not the blue of a ripe blue berry or wild grape. It’s more like the blue paint job of of a customized Gran Torino from the 1970’s. It really looks out of place in in the natural habitat.

The berries are about 1/4 to 3/8 inch in diameter.

The berries are about 1/4 to 3/8 inch in diameter.


Silky dogwood prefers low lying areas along streams or ponds. However, ours is growing in one of the higher spots in the yard, which is why I chose that area for the chicken run, so that the hens would have a high and dry area to roam. I know we have a fairly high water table here, and that is probably why the bush is growing so well.

The dogwood has a beautiful natural shape and bright shiny leaves that make it a very attractive plant. I don’t see many of these around anymore. In some states, like Indiana, where it was once common is now considered a locally endangered species.

In some parts of the country it grows to a maximum height of around five feet while in others, it can get 10 feet high. Mine is at least eight feet tall. My guess is that it all depends on its location or local population genetics.

The berries contain high amounts of fat, compared to other berries, and that makes it a favorite for migratory birds that need fat to sustain them during their migration. Flocks of cedar waxwings have found our wild area and are eating the wild cherries. So far they haven’t touched the silky dogwood berries. Maybe they’re not quite ripe enough for them yet.

I’ve never been tempted to try to eat these berries, even as a young child. Something about that blue just didn’t look right to me. I don’t ever plan to eat them so I’m not going to tell you whether or not they are edible, you’ll have to do your own research. Let me know in the comments section what you find.

I recall that some groups of native Americans used the the bark as part of their tobacco mixture called kinnikinnick. I’m not sure if it was used as a flavoring ingredient or if it has some sort of medical or other value.

Even if you don’t to smoke it or eat the berries, silky dogwood is an attractive shrub to use in your landscape especially if you have a damp problem area where other shrubs fail to thrive.

Seeds, seeding and plants are available online and at nurseries.


More tree frogs in our garden this year

July 21st, 2015

It sure seems like our garden has become a haven for baby tree frogs. Standing in one spot without having to move, I could see three of them. I’ve also seen a lot more hopping around in the yard.

Tree frogs need water to reproduce, either permanent ponds or temporary pools of water. This wet summer with all of its rain has left a lot of standing water around. Some areas around here have had water standing for a couple of months, long enough for tree frogs to lay eggs, hatch into tadpoles and develop into frogs.

The little frogs are easier to spot on flowers.

The little frogs are easier to spot on flowers.

Like other frogs, they eat all sorts of insects which makes them helpful in the garden.

They’re so much fun to watch too. Tree frogs blend in so well with their surroundings that it is hard to find them in their natural habitat up in the trees. They can surprise you by showing up in the most unusual places.

Waiting for a meal to come his way.

Waiting for a meal to come his way.

Many of us have seen them resting on windows or stuck on the side of a building. One time I was happily surprised by one sitting on an apple I was about to pick.

Adult tree frogs are about two inches long, ours are a little over half an inch right now. They range in color from gray, brown or green depending on their circumstances.

Compare the size of this tree frog to the width of the daylily leaf.

Compare the size of this tree frog to the width of the daylily leaf.

I believe tree frogs are loudest frogs we have around here. Their call is distinctive and carries quite a distance. Like bird songs, you can learn to identify them by their call even if you can’t see them.


Wet weather now may contribute to gnarly tomatoes later

July 15th, 2015
Heirloom variety 'Stupice' tomato flowers.

Heirloom variety ‘Stupice’ tomato flowers.

I don’t have to tell you we’ve had more rain than usual this gardening season in southeastern Michigan. Some locations, like my garden, have had significantly more rain than the official reporting stations because of localized heavy down pours. Don’t be surprised if you see a higher proportion of misshapen tomatoes in your garden this year be cause of this.

If you’ve grown tomatoes for any length of time, I’m sure you’ve picked your share of distorted tomatoes.

You may remember from your high school biology class that a tomato develops from the female parts of  a flower — the ovary and ovule. Under good weather conditions the tiny, newly formed tomato grows and matures normally. But when the weather doesn’t cooperate, tomatoes can develop a number of different problems.

Tomatoes that have distorted areas with rough, brown edges are called “catfaced”. Although they are safe to eat, they don’t look very attractive. Catfacing is most often caused by flower petals sticking to the ovary just as the tomato begins to form. Rainy, damp weather keeps the petals from drying completely and separating from the rest of the flower.

“Zippering” is another related condition caused by damp weather. The symptom is, a long, rough, thin brown scar running longitudinally — north pole to south pole — on the skin of a tomato. It’s caused by the anther, the male part of the flower, adhering to the young fruit as it grows.

Sometimes an open locule forms along with zippering. A locule is a chamber inside the ovule that produces the fruit part of the tomato. An open locule is also called an “open hole”. It shows up as a dry, brown hole or depression on surface of the tomato.

Those over-sized, distorted tomatoes that look like two or more tomatoes merged into one, are also caused by poor weather during flower development.

Some varieties are more prone to these disorders than others — the “Beefsteak” varieties being one common example.

I should stop here and mention “blossom end rot”. It is not related in any way to these disorders but is caused by inefficient movement of calcium inside the tomato. That is a discussion for another blog.

Distorted tomatoes can also be caused by high soil nitrogen, excessive plant pruning, exposure to herbicides and tomatoes rubbing against one another.

As the weather straightens out, tomatoes forming later in the season will have fewer catfacing and zippering symptoms at maturity.


Too much rain causes waterlogged garden soil

June 30th, 2015

Gardeners in our area are having to deal with unusual amounts of water in their gardens. The amount of water in the soil is more like what we would see in early spring after the snow melt rather than late June or early July.

Driving around I see standing water all over our area with no place to go. Soils in many places are waterlogged which means big trouble for plants.

Most plants are able to cope with a day or two of flooding but after that, complications start to set in. The biggest problem is a lack of oxygen in the soil. Plant roots need oxygen to function.

All types of soil contain air spaces between soil particles. Fine textured soils with a lot of clay, have very small air spaces while sandy soils have large air spaces. This is very important because plant roots need access to soil air, they can’t efficiently use the oxygen dissolved in water.  When we have too much rain, these air spaces fill with water. Once that happens, the plant roots begin to drown and eventually die.

A water damaged plant, curiously enough, shows symptoms exactly like a plant that has been growing in a drought. In the case of a drought, there is not enough water for the roots to absorb so the upper part of the plant wilts. With a waterlogged plant, the upper part of the plant also wilts because can’t the roots have stopped working so no water gets moved into the upper parts of the plant.

After a the soil returns to normal, plants need to be watered more often because they have fewer roots. Often, if the damage is not too bad, the plant will recover by growing more roots to replace the ones lost by drowning. If it the damage is too great, the plant will be stunted and never be able to live up to its potential.

Raised beds are helpful in low lying areas.

Raised beds are helpful in low lying areas.

Another problem, especially with a vegetable garden, is the potential for contamination. In urban or suburban neighborhoods where all sorts of properties are nearby, there is the potential for flood waters to carry contaminants like bacteria or chemicals. Think of that dog kennel down the street or that parking lot with runoff water carrying motor oil and other debris.

You may want to think twice about eating vegetables exposed to contaminated flood water.


Moth mullein welcome in the garden

June 29th, 2015

There’s some new unexpected members to our garden family of plants this year. It is a group of moth mullein plants.

I’m not really sure how they got there. I figure they most likely hitched a ride as seed in soil from some other plants that I transplanted from someone else’s garden a couple of years ago.

Since moth mullein is a biennial, it takes two years to bloom. The first year for all biennials is a nondescript growing stage which is why I hadn’t noticed the mulein until now. If I was a more tidy gardener, I probably would have pulled them out last year thinking they were some kind of weed seedlings.

Moth mullein is a non-native species so, many people consider them actual weeds. Originally they were brought to this continent as a decorative flower and useful herb — it has some insecticidal properties.

Moth mullein in bloom.

Moth mullein in bloom.

While it may be an immigrant to this country, moth mullein seem to have very little impact on the native ecosystems of our area. They really can’t compete with well-established native plants. However, each plant produces thousands of seeds a year and tilling the soil tends to stimulate their germination. In the garden they may eventually wear out their welcome. In some states they are classified as noxious weeds but not here.

American goldfinches feed on the tiny moth mullein seeds. I saw a pair of goldfinches checking out my plants today. The seeds are not ready yet, so they decided to leave before I could get a photo of them. The seeds are pretty small, about one millimeter long, and can sprout even after laying for a hundred years.

I’m not too worried about the mullein taking over my garden just yet. They are behaving themselves in a very dry flower bed and are only a couple of feet tall. In your garden, if it has fertile soil and is well watered, they might grow twice that size.

Moth mullein is a perfect candidate for an English cottage garden where plants are expected to reseed themselves year after year.

Seeds are available through mail order seed catalogs and online sellers. Of course you can always collect some from the wild since they are not endangered nor invasive in Michigan.


Easy to grow iris give plenty of color

June 10th, 2015

Iris are one of my favorite flowering plants for a number of reasons but mainly it’s because they are so easy to grow compared to some other plants. I’m not the only that knows this which is probably why you see so many irises in gardens.

Although there are several types of irises, the one that everyone thinks of when you say “iris” is the bearded iris sometimes called German iris. Irises put on quite a show in return for comparatively little effort on our part.


Irises are perennials, which means plant them once and they’ll come back again year after year. They are very resilient plants and are quite cold tolerant. Ours when un-mulched, came through two extremely cold winters and never missed a step.

Bearded irises require well-drained, sunny locations to thrive. Soggy soil, especially during the summer, will cause their roots to rot. On the other hand, they need plenty of water during the early spring, shortly after they wake up from their winter dormancy. Around here, we usually get enough rain in the spring for them to be satisfied.

The most common mistake beginners make when planting iris is to place them too deep into the ground. Only the bottom two-thirds of the root rhizome gets covered with soil. The other on-third is above ground as I heard someone say, “like an alligator”.

German irises grow so prolifically that they will over-crowd themselves over time. So, every three or four years they need to be dug up, divided and replanted. It’s a relatively easy thing to do and you don’t have to worry much about hurting the plant. I’ll discuss this in a post later on this summer as we get near thinning time.