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.

Bob

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.

Bob

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.

Iris

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.

Bob

Rare opportunity to see blooming satsuki bonsai azalea

June 10th, 2015

I think just about everyone enjoys looking at bonsai, the Japanese art of growing miniature trees in containers, Even those who are not particularly interested in plants will stop and take a second look at bonsai.

The University of Michigan Matthaei Botanical Gardens near Ann Arbor, is offering a rare treat this month, Magnificent Miniatures a showing of satsuki bonsai azaleas in full bloom.

satsuki bonsai

The plants are on loan from Dr. Melvyn Goldstein a renowned bonsai collector from Ohio.

satsuki bonsai

The bonsai are flowering right now. And like other flowering plants, the flowers only last for a short period of time.

satsuki azalea bonsai

The show is free and runs from June 6 through June 14, 10 am – 8 pm daily. It’s an easy drive to the Gardens from anywhere in southeastern Michigan. The address is 1800 N. Dixboro Road, Ann Arbor.

It might not be a bad idea to call ahead to make sure the bonsai are still blooming 734-647-7600.

Bob

Double — even triple– your pepper yields

May 28th, 2015

If you’ve never had much luck growing peppers, you can vastly improve your pepper yield by doing a bit of extra work now before the plants go into the garden. The secret is to use plastic mulch.

In the past I’ve experimented with several colors of plastic mulch: clear, black, red, blue and silver. All of them showed a huge improvement over organic mulch or no mulch at all.

Using plastic mulch is not a new concept, it’s been around for decades. Commercial farmers and researches have improved yields even more than double.

There are several reasons why plastic mulch works so well. The most obvious is reduced weed competition. Plastic mulch prevents nearly all weeds from growing by blocking sunlight to the soil. The only weeds that you have to contend with are those that sneak up through the hole made in the plastic for planting. The exception is clear plastic mulch. It lets sunlight through allowing weeds to thrive under the greenhouse-like conditions.

Whenever you hoe or till around plants, no matter how careful you are, valuable surface roots get cut. Since plastic mulch keeps weeds from growing, there is no need for hoeing or cultivating except in pathways between the rows of mulch.

Soil temperatures are warmer under plastic mulch which is important in a relatively cool environment like Michigan. Peppers are warm season crops that respond well to warm soil temperatures. Organic mulches on the other hand, tend to keep soil temperatures cool.

Oxygen is critical for plant roots. Garden soil under plastic stays loose, leaving space between soil particles so that air can move. This creates a better environment for plant roots and soil microbes to do their job.

Bare garden soil loses a lot of water through simple evaporation. Plastic mulch keeps the soil from drying out allowing more water for the plants to use when they need it.

Some plant diseases are spread by rain or irrigation water splashing soil up onto the plant. Plastic mulch keeps plants clean and less susceptible to disease infections.

Carbon dioxide is produced in the soil and is a normal part of the soil dynamic.  On bare soil it diffuses directly into the air. Since gases can’t pass through plastic mulch, carbon dioxide tends to collect in very high concentrations underneath the plastic sheet. It can only escape by moving through the planting holes resulting in very high levels of C02 right at plant level where the plant can efficiently use it for increased photosynthesis producing higher yields.

Black is the default color of plastic I use in my garden. Mainly because you can find it just about anywhere, although I’m seeing more red plastic around lately. Also, black plastic is available in heavier grades than the colors allowing you to use it for more than one season if you want. I never use clear because of the weed problem I mentioned earlier.

Heavier grades of plastic mulch can be saved and re-used the next year.

Heavier grades of plastic mulch can be saved and re-used the next year.

This may sound obvious but, lay your plastic before planting, it will be much easier to transplant through holes in the plastic. I had an assistant years ago that transplanted the plants first and then tried to install the plastic. He got it to work but it was a chore.

It’s important that the surface of the planting bed is smooth and flat, sloping slightly so rain water can run off.  Rake out all debris and don’t step in the prepared soil.

Farmers use special machines to lay plastic in their fields but we don’t need anything like that in a home garden. I just stretch a string where I want the edge of the bed to be and dig a trench. I unroll the plastic and bury one edge with soil. Then I measure the width I need for the second trench — allowing for covering the opposite edge — stretch the string again and dig my second trench. A 48 inch wide roll gives me a planting bed just over three feet wide.

I cut an “X” through the plastic where I want the plants to go and transplant through the cut.

It takes some time to properly prepare the bed and install the plastic but you will be amazed by the results.

Bob

Start a new tradition throw a daffodil party

May 9th, 2015

Are booming daffodils a good excuse for throwing a party? It is if you are Dick Deionne of Ann Arbor.

Each spring he throws a daffodil party where he treats his friends to the spectacle of thousands of daffodils that includes dozens of different varieties.

Beginning gardens should  be aware that daffodils are planted in the fall.

Beginning gardens should be aware that daffodils are planted in the fall.

Most of his plantings are under trees or around the edges of the wooded areas.

Daffodils thrive in rich woodland soil.

Daffodils thrive in rich woodland soil.

Normally black walnut trees are troublesome for flowers because of a poisonous chemical that walnut roots release into the soil. This makes the area in the tree’s root zone unsuitable for most plants. Daffodils are resistant to the chemical and do well under black walnut trees.

Daffodils grow happily under black walnut trees.

Daffodils grow happily under black walnut trees.

A few daffodils in the garden are nice but a planting like this makes quite a statement.

A few daffodils in the garden are nice but a planting like this makes quite a statement.

If you want to start your own version of an annual daffodil party, keep in mind that daffodils are planted in the fall. Flower bulb sellers start taking orders for daffodil bulbs in mid-summer for fall delivery.

Bob

 

 

Never pruned apple trees before? Here’s five fool-proof cuts you can make

April 22nd, 2015

Although you can prune apple trees just about any time of the year, most apple growers agree spring is the best time to do it. You may have seen professional orchardists out pruning trees as early as February but that is only because they have so many trees that they need the extra time to get them all pruned before the growing season starts.

Pruning and shaping apples trees takes some knowledge and experience to get it right but there are a few cuts you can be sure of even if you’ve never pruned an apple tree before.

Before pruning remember to make the cuts near the junction of the twig or branch and the main branch or trunk. Don’t leave a long stub. Conversely, don’t cut into the trunk or main branch, that makes it difficult for the tree to heal. Try to leave just a small “collar” to allow for proper healing.

You’ll need two basic tools:

1) Use a sharp pair of pruning shears for twigs and small branches.

2) Loppers resemble over-sized pruning shears. They are much more sturdy than shears, have longer handles and are used for for cutting larger branches.

 

Anvil pruners (left) are OK but, to make the cleanest cuts use the by-pass type (right).

Anvil pruners (left) are OK but, to make the cleanest cuts use the by-pass type (right).

Here’s five basic cuts to make when pruning apple trees:

1) Cut off all dead twigs and branches. The spot where they attach to the tree provides a entry point for disease and other pests. Once a branch dies, the tree will try to heal around the dead branch. Unless the branch is cut off or falls off naturally, healing will never be complete.

2) Prune away “suckers”. They are those thin shoots that grow up around the base of the tree. They don’t contribute anything to the tree and make their growth at the expense of the rest of the tree.

3) Help increase light penetration and improve air circulation through the tree by removing all “water-sprouts”. Those are thin shoots that grow straight up from the main branches. They don’t produce fruit and will grow larger each year eventually distorting the tree.

4) If two branches are rubbing against one another, remove the weakest one. Rubbing damages bark leaving a wound for disease organisms to enter the tree.

5) This one will take a little more thought. Prune away weak branches that are shaded by more vigorous branches. Even though they may produce fruit, it won’t be the quality and volume produced by stronger branches. If you are fortunate enough to have inherited a mature apple that has been properly pruned through the years, it’s easier to tell which are the weaker branches.

There is much more to proper apple tree pruning but these five cuts will go a long way to improving the health of your tree and building your confidence for more sophisticated pruning.

Bob

Behind the scenes at Matthaei Botanical Gardens

April 22nd, 2015

Mark May 10 on your calender, although it is probably already marked. That’s because it’s Mother’s Day and by default, Mother’s day is always shown on all calenders.

However, there is another reason to mark that day. It is weekend of the annual Spring Plant Sale that happens at University of Michigan Matthaei Botanical Gardens in Ann Arbor.

Recently, I had a chance to go behind the scenes and got to see how preparations were coming along for the Spring Plant sale.

The day I was there, staff and volunteers were tending thousands of growing plants. They were also designing and planting many, many hanging baskets and containers for the fund raiser.

Collections and natural Areas Specialist Adrienne O'Brien leads a team of University of Michigan student workers and adult volunteers that plan, plant, grow  and design containers and potted plants for the plant sale.

Collections and natural Areas Specialist Adrienne O’Brien leads a team of University of Michigan student workers and adult volunteers that plan, plant, grow and design containers and potted plants for the plant sale.

The sale is a great excuse to take a trip to the Gardens. See you out there.

Bob

Super-sized Christmas poinsettias are started now

March 29th, 2015

Holidays for horticulturists usually have two dates.  First, there is the actual date that the holiday occurs. The second date is the time when plants associated with that holiday need to be started.

Greenhouse people are beginning to make preparations for Christmas now, in very early spring .

I’m sure you’ve seen giant-sized poinsettias in full bloom during the Christmas season. Did you ever wonder how they managed to get them so big? The secrete is to keep the same poinsettia plants growing year after year.  Each year the plants get bigger and produce more colorful bracts.

If you have a poinsettia that is still alive from Christmas, you can renew it and have a larger more colorful plant for next Christmas.

 

A bench of pruned poinsettias at Matthaei Botanical Gardens, Ann Arbor.

A bench of pruned poinsettias in Greenhouse 3 at Matthaei Botanical Gardens, Ann Arbor.

Start by pinching off all of the leaves and bracts from the plant. Many of them may have already dropped off anyway by now. Next cut the main stem or stems to about six to eight inches above the soil surface. Remove the plant from its pot.

This pruned poinsettia is just beginning to make new growth.

This pruned poinsettia is just beginning to make new growth.

It’s best to carefully rinse the old soil off of the roots and re-pot the plant using new potting mix. Removing the old soil is not absolutely necessary though, I’ve had very good results by simply leaving the existing soil then re-potting into a larger pot. What is necessary however, is using a loose commercial potting mix, not soil from the garden. Poinsettias need loose soil, no ifs ands or buts.

Then water thoroughly — soak the pot with water and let it completely drain out. Never let poinsettias sit in the water that collects in the pot saucer, they just can’t tolerate wet feet.

Put it in the brightest area you have to encourage it to grow. Once you see shoots developing, feed it with a good house plant fertilizer about once a month.

Later, after the danger of frost has passed, place the plant outside in a bright spot that has dappled shade during the hottest part of the day.

As the plant grows through the summer, you can pinch back shoots to help keep a symmetrical shape. Pinching will also stimulate more branching giving the plant a more compact and bushy look.

With some care and luck you’ll have a stunning plant to show off next Christmas.

Bob

 

Snow cover helps plants through harsh winter

March 25th, 2015

Our second bitterly cold winter in a row is finally over. Even though this winter was not as cold as last year’s, it still made the record books as one of the top twenty coldest. It’s kind of surprising to me how quickly it ended. Just a few days of moderate temperature erased the snow.

The plants in our area look to be in pretty good shape despite those cold temperatures. We can thank the continuous blanket of snow that was covering the ground all winter.

Snow is nature’s insulator. I’ve heard people say they were worried because snow would freeze their plants. I’ve had to point out to them that snow is a gardener’s best friend , especially if you have perennial flowers and small fruit such as strawberries.

Farmers who grow winter wheat — which is planted in the fall — pray each year for snow cover so their wheat crop is not damaged by exposure to cold temperatures and desiccating winter winds.

Despite the fact that I neglected to mulch my strawberries as I usually do, they look to be in great shape.

The garlic I planted last fall looks good too. There was no covering on those either except what nature provided in the way of snow. I got lucky this time skipping the mulch, I don’t plan on ever taking a chance like that again.

The mud season around here was pretty short too, it lasted only a few days. The mud I’m talking about is that mud that forms when the surface layer of the soil thaws but the lower layers are still frozen. That surface water has no where to go so just turns into mud especially if poultry or livestock are walking over it.

Since the soil was not frozen very deep around here — again thanks to the continuous snow cover — it was able to thaw out very quickly.

One other surprise I found was a couple of rows of spinach that were still green and beginning to make good growth. Without that snow, they would have been frozen out way back in November.

The snow cover provided plenty of protection for a small row of spinach.

The snow cover provided plenty of protection for a small row of spinach.

It looks like we’ll be eating an early salad from the outdoor garden this year.