Pruning Do's and Don'ts

Palo Verde in bloom; taken in June

Last weekend, I went to another session of working in the garden at the Tucson Botanical Gardens and again, it was another meaningful session that focused on garden maintenance and pruning.  This particular article will focus on the pruning part as I thought it was interesting.

One of the greatest mysteries for me about gardening is how to prune a tree....I know when you clip a branch, several sprouts will shoot out from around the end.  With trees, it's trickier and could be a very costly mistake.  I have always called on the professionals to do that particular job not only because of the height of the tree and the use of heavy equipment, but also because I want to make sure I don't damage these important plants in our landscape....like my 2 80+ year old oak trees.   In February or March, I begin the "hair cut", but I only do this when the trees need it and it's definitely not every year.  A healthy tree should have space between the branches for air to move.  There are 3 important cuts that I discovered. The illustration is above....
Cut 1.  It's the mini cut under the branch so that the bark won't peel away in case a limb falls and damage the tree.
Cut 2. Is the major cut....close to cut one that will remove the weight.
Cut 3.  This is the delicate cut in which you will cut closely to the branch or trunk.  This is THE most important cut of them all because you will want to make sure your tree heals properly. 
Remember that branch angles in formation of U or much better than a V.  A U formation creates a stronger tree.

Lion Tailing is bad and ruins a tree. It is the removal of all the inner laterals and foliage. It then causes weakend branch structure and breakage. This is what I like to call the weird "Umbrella" look. It also makes it prone to tip over during our monsoon storms...especially during a microburst. I have noticed that people use a similiar strategy with crepe myrtle....again this technique weakens the structure of the tree.  It is commonly done by professional landscapers so be careful.  If you are paying someone to trim your tree(s) and you care about your tree(s), you should stay home and watch the procedures done.  There is nothing worse than you getting home and seeing a favorite plant butchered by someone else's hand.  I stay home on those days with my arborist and go over any procedure before he does it.  He's a great guy and I trust him, but I want to know what he's going to cut before he does anything to my plants. Education is everything!! Usually he comes to me the day before and we go over the details. On the following day with his crew, he'll work his magic.:)

Adding tar on a tree cut is not recommended and it will, on occassion lock in bacteria, etc and begin killing the tree.  The only recommended action, of this type during our discussion, was painting the citrus trunk white to protect against the sun burn.  Citrus plants are not meant to be trees as they are really bushes.  However, people like the tree form better and cut all the branches and leaves that naturally protect the trunk from the sun. Personally I like the citrus for the bushier look.

When should someone prune a tree?
-when there is dead wood
-when there are crossing branches
-when there is diseased wood

NEVER TOP A TREE
NEVER REMOVE MORE THAN 20% OF THE PLANT(some say 25%)

What type of equipment do I use?
-Hand pruner for a branch less than 1/2 inch
-Loopers for a branch up to 1 inch
-Pruning saws for anything thicker

Pruning Young Trees
-Do not remove lower branches for 2-3 years as the goal is to establish a strong trunk
-Establish desired branch spacing
-Avoid pruning in hot weather to avoid sunburn on trunk

Reason for Pruning Mature Trees
-Crown cleaning
-Crown thinning
-Crown reduction
-Crown raising or elevating(so that people can walk under the tree)

When to prune
-in Spring as it encourages growth
-in Fall to reduce plant size but it is suggested that you avoid fall pruning as it is slower to heal and more likely to decay from cold and wet weather.....so wait until Spring:)

A tree should be
1/3 Trunk
2/3 Canopy

Wooden stakes?
"Yes" to keep the rootball from tipping over during a windstorm and "no" to keep a tree to bend a certain way. Two stakes if you use this method.
I stake at my place for newly planted trees only so that they don't fall out or tip over from their freshly made hole.  Trees need to have moving space so that when the wind blows the trunk around, it will send signals to its' root system strengthening it into the ground.

Watering new trees.
The irrigation drip should be kept close the first year and moved further away as the tree gets older so that it can extend it's roots into further ground.  A tree will tip over if the water line is not moved after the first year as this encourages the tree's roots to stay in one place.  I've had personal issues with this particular problem.  I lost two beautiful trees that way because I didn't move the drip system away and it killed me....two year of love and they die!! Trees should have their roots a depth of 18 to 36 inches.

It was a lot of information, but I felt like it was one of the best classes yet.  Hope this helps you in your own garden....until my next blog on garden maintenance:)