Pruning Tips
Copyright 2010 McGroarty Enterprises Inc.

The most common and often made pruning mistake will completely ruin, and render your landscape plants worthless.   Be careful not to make this huge mistake.  What is it?

Not to prune.  Pruning is essential to health and well being of landscape plants.  If you don't prune them when they need it, they will get very, very ugly.  It's true, and yet this is the most common of all pruning errors.

People are afraid to prune.  They are so concerned that if they don't do it right they will ruin the plant forever.  Pruning a plant improperly is not likely to ruin it forever.  It's like a bad haircut, it may not so good right now, but it will grow out.

Last spring we sold over $25,000. worth of our 
little plants right from our driveway in a
 matter of about six weeks!

Click here to see one of our plant sales, photos 
of our house, and our backyard nursery.

Not pruning on the other hand is a missed opportunity.  If you skip  pruning this year, you are going to lose a years growth if you properly prune the plant the following year.  Pruning is best done a little at a time.  You can't save it up and do it all at once.

Two years ago I bought two Forsythia so I could take cuttings from them.  They were about 4' tall but they were really ugly plants, so at the end of of the season I cut them back all the way to about 10" high.  You can do this with fast growing plants.  Often times a plant like this that has not been properly pruned will only have two or three main stems.  By cutting it back heavy it will branch out with at least two branches for each one that you cut off.

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This spring my Forsythia took off growing, and I made the big mistake.  I just let them grow.  The only pruning I did was to take a few cuttings from each plant.  Now they are 4' tall once again, but they still are not nice plants, so I am going to have to cut them back heavy again this winter.  Now next year if I'm smart, as soon as they start growing I'll prune them lightly, just clipping the tips off the new growth.  This will slow them down, and force them to send out more branches everywhere I make a cut.  Then I should do this every few weeks.  If I do I will have nice, tight, full plants.

Not all plants are as vigorous as Forsythia, but the same principle applies to all plants.  Prune them as often as they need it to keep them nice and full.

Keep in mind that most shrubs, especially the fast growing ones, have a tendency to grow in the shape of vase.  You want to prune them to keep them from taking on this shape as much as possible.  When they grow like a vase, the top of the plant shades the bottom, and without adequate sun the bottom of the plant will get very thin and woody.  Trim the sides straight up and down as much as possible to keep this from happening.

When you are pruning make sure you remove any broken or scarred branches.  These are a nothing but an invitation to insect and disease.

Prune all of your flowering shrubs immediately after they have finished blooming, including Rhododendrons and Azaleas. Especially Rhododendrons and Azaleas, because they start setting flower buds for next year during the summer. It takes them almost a full year to produce a flower bud.  While your at it pick the spent blooms off your Rhododendrons so they don’t waste valuable energy producing seeds.

Some plants such as Potentilla, Rose of Sharon, and hydrangea flower on the current years growth.  In other words the plants take of with vigorous growth in the spring, and then start producing flowers on the tips of that new growth.  Plants such as these should be trimmed heavy in the fall, and then you won't have to trim them during the summer, and the flowering cycle will not be interrupted.  

     Watch those grafted plants
in your landscape

This is a common mistake made by home owners who don't understand the nature of a grafted plant.  A grafted plant is a actually two plants in one.  Grafting is a technique where a small section of one plant is attached to another plant, and the two pieces then grow as one plant.  The purpose of this is to provide a straight stem, or a good strong root system for plants that don't have the qualities. 

Most rose bushes are grafted onto a strong root stock.  You've probably heard somebody talking about a rose bush reverting back or growing wild.  What actually has happened is the desired rose bush, the grafted part, has died, and what is now growing are just suckers from the root stock.  When this happens you might as well dig out the plant and throw it away, because the beautiful plant that you bought is dead, what is left is just an undesirable plant that is as strong as an ox.

Weeping Cherries are usually grafted on to a root stock that is just another form of a cherry tree.  Sometimes this done is down low right at ground level, and some times it is done up high to create the umbrella effect that people like so much.


Bottom Graft Weeping Cherry

The above photo is a Bottom Graft Weeping Cherry.  Unlike the top graft variety this tree produces branches all the way up and down the stem that weep.  Because this entire plant is of the weeping habit, you have to train it to grow upright.  I do that by tying it to a stake.  �" electrical tubing makes a good stake, and is available at most hardware stores.  I have been working with this tree for a few years, and still have more work to do.  My goal is for it to weep from the very top.  As the top of the tree develops, I continue to remove branches from the lower part of the tree. 

As the tree grows you have to trim the branches to form a nicely balanced tree.  A single wrap of duct tape works good for anchoring the tree to the stake because after about 10 months the sun dries the glue on the tape and it falls off, which is important.  If you use something that will not fall off, it could actually girdle the plant, which restricts the flow of nutrients, thus damaging the tree seriously. 

As you can see in the photo below, a Bottom Graft Weeping Cherry that is not staked or trained will not grow at all upright on it's own.  This plant was not trained and it grew wide and flat like a low table.


A Bottom Graft Weeping Cherry
that has not been trained to grow upright.
Click on the photo to enlarge it.

The picture below is a Weeping Cotoneaster.   Actually what you are looking at is Cotoneaster Apiculata grafted on to a Paul's Scarlet Hawthorne tree.

In the above photo the stem and the roots are one plant and the branches that make up the head of this tree are another.  When pruning any plant that is grafted as this one is, you have to watch for new growth coming from the stem.  Any growth coming from the stem must be removed as this growth is not desirable.  Anything that grows below the graft union should be removed.  The graft union is up high, under the canopy.  Upon close inspection you can see a distinct difference in the color and texture of the bark where the two plants were joined.

The above photo is a top graft weeping cherry that has suckers growing from below the graft union.  Notice that the suckers have leaves while the rest of the tree is yet to leaf out.  That's because this picture was taken in early spring and since the rootstock is one variety and the weeping part is another variety, they leaf out at different times in the spring.  These suckers need to be remove and should have been removed two or three years earlier.  

The easiest way to do this type of pruning is to catch these little sprouts when they are still a single leaf and just pick them off with your fingers.

I see plants such as this one, Weeping Cherries, and Japanese Maples where people don't realize what is happening to their plant.  All kinds of growth is coming from the root stock and the people just let it grow because they don't realize that it should be cut off.  If this new growth is allowed to grow it will completely ruin the appearance of the plant.  And usually the growth coming from the root stock will grow much more vigorously than the desired variety, ruining the plant that much sooner.

The same thing is true for plants that are budded or grafted at ground level.  This is how most flowering crabapples are grown.  The desired variety is budded on to a generic root stock.  Budding is a form of grafting where a single bud is slipped under the bark of the root stock.  That's why you often see crabapples with all kinds of suckers around the base of the tree.  These suckers are coming from the root stock, and they should be removed. 

Don't just clip them off at the ground, because they will just come back in abundance.  I use a digging spade and get right to the point of origin from the roots and remove them completely.  Using this technique they are quite easy to control. 

Root pruning can breath new
life in your plants.
       

How in the world do you prune the roots of a plant?   First let's discuss why you should prune the roots of a plant. 

As plants grow the roots grow as well.  The roots usually grow in an outward direction from the plant.  If let go they just keep growing outward, and at the same time the diameter of the roots increases.  The tissue on the outside of these roots becomes hard and less porous, and their ability to absorb nutrients decreases. 

Severing the roots of the plant actually causes the plant to produce new little fibrous roots that have a much greater ability to absorb nutrients.  For each root that you severe the plant will replace it with several small fibrous roots, greatly increasing the plants ability to absorb nutrients. 

Root pruning can improve the over all performance of a plant, including it's ability to produce flower buds.

To root prune a plant you must first establish exactly where you want to severe the roots.  To do this measure the diameter of the stem approximately 6" up from the ground.  The rule of thumb is 12" of root zone for each 1" of trunk diameter.  This is where you are going to cut around the base of the plant.  For a plant with a 2 inch diameter stem you should cut a 2 foot diameter circle around the plant.  For shrubs just cut at the drip line, which is the point on the ground where rainfall running off the plant would hit the ground.  

To severe the roots just dig a small trench around the plant approx. 6" deep, and then place the blade of your spade in the trench.   Using your foot force the spade into the ground as deep as you can, continuing this all the way around the plant.  You may not cut all of the roots, but you will cut enough to give your plant a jump start.

Fall Pruning

Fall is a good time to do heavy pruning.   Even if you have a flowering plant that already has next years flower buds in place, if it needs it, prune it.  You might salvage a few blooms by waiting, but you are doing so at the over all well being of the plant. 

When you do heavy pruning on a tree during the winter, it will set new buds and take off growing like crazy as soon as spring arrives, sending up branches that look like suckers.  On the other hand if you do this pruning during the late summer, it will take the tree a few weeks to set new buds, and by the time they start to grow the season will be coming to end, greatly reducing the growth of these new branches.  Over the winter the tree will set more buds on this new growth, so come spring the tree will not take off with that wild burst of growth.

Heavy wet snow can often damage trees and shrubs.   Proper pruning is required to restore these plants back into beautiful specimens once again.  Broken branches should be pruned as soon as possible. Leaving broken and split branches hanging is an open invitation for disease and insects.

When pruning shade and ornamental trees remove any damaged or dead branches first. Then begin removing branches from the inside of the tree. If there are two branches that are touching, one of them should be removed. You don’t want branches rubbing together causing damage creating more opportunity for insects or disease.

Branches growing toward the inside of the tree should also be removed. There is no point in allowing these branches to continue growing. They will not receive adequate sunlight and will eventually die anyway.

After you have removed the broken, the dead, and the ill directed branches stand back and look at your tree. Now trim it for balance. If the storm did considerable damage to one side of your tree you may have to trim the other side in order to balance the tree.

Make your cuts clean and smooth. There is conflicting information about sealing pruning wounds. The old school says seal any wound larger than a dime with a good quality pruning paint. More recent research says it doesn’t seem to make any difference at all. My advice is to seal large wounds. If it doesn’t help the tree, it will at least make you feel that you did all you can.

Many  evergreens often get  pulled down by heavy snow and return to their original position on their own. Taxus, Hemlock, and Spruce seemed to fair pretty well.  However, Arborvitae and Juniper varieties suffer the most damage. These plants have a tendency to produce multiple leaders when they are very small. This doesn’t pose much of a problem until the plants grow large. Large plants of these varieties with multiple leaders always separate and pull apart when a heavy snow comes.

If you have evergreens that spread open and out of shape the best thing to do is to tie them up with a cotton or sisal type of string. This type of string is biodegradable and if left on will do no damage. Nylon string or wire will be there forever and could cause problems when you prune later on.

A heavy snowfall helps to separate the good landscape plants from the mediocre landscape plants. For years I have been preaching to new homeowners that plant selection is everything when designing a landscape. People who find themselves in a situation where they need several hundred dollars worth of nursery stock are always tempted by those low priced plants at the garden center. After all, some of the best looking plants on a retail sales lot, actually are the lowest priced. But just as everything else in life, you get exactly what you pay for.

Garden centers can sell these low priced plants for less because they buy them for less. Wholesale nurseries sell them for less because they are easier to grow and can be produced in less time than higher quality plants. However, in the long run they do not perform as well. They are usually quick growers and will out grow the area they are put in quite quickly.  They usually grow at a faster rate than other plants in the landscape, and soon the whole planting is out of proportion.

Arborvitae are a good example. Unsuspecting buyers see Globe Arborvitae on the sales lot and jump at the chance to get such a nice plant at such a fair price. They just know that these beautiful green plants are going to look just great around their home. And they are right. They will look great, . . . for a while. But a few years later when a heavy snow comes they will be flatter than a pancake. Well maybe not quite that flat, but they will be pushed open revealing all the dead needles inside the plant. They will never look good again. That won’t happen if you plant one of the Taxus varieties. Of course you will pay more up front, but Taxus will perform well for many, many years.

Remember, the higher the price of a plant, the higher the quality, and the better the performance over the long haul.

Last spring we sold over $25,000. worth of our 
little plants right from our driveway in a
 matter of about six weeks!

Click here to see one of our plant sales, photos 
of our house, and our backyard nursery.

by Michael J. McGroarty
Copyright 2010