April 2012


 Training goes hand in hand with pruning to develop a stronger and more productive tree.  One of our goals is to develop healthy crotch angles between the scaffold branches and the trunk.  A narrow angle of less than 45 degrees is much weaker and susceptible to damage from winds, snow or heavy fruit loads.  The narrower it is, the weaker it is.  Sometimes these narrow angles will spit some leaving a possible entry site for infection. 

Many apple varieties are more vertical in their growing habits than others, so look carefully at your trees by type. Some will require minimal maintenance; others it seems need help with every branch.  All European

Pears have very upright branching habit

Pears are prone to vertical growth and usually require some intervention for best production. Our aim is to get the main scaffold branches to develop a crotch angle of 45 degrees or even more.  This training should be done in the spring (now is a perfect time) while the branches are limber.  By mid-summer they become rigid and are easily broken.

This process is usually aided by the use of “branch spreaders”, a fancy term that means anything you can wedge in between the branch and trunk to spread the branch more horizontally. Sticks which are notched at the ends are perfect, paint stir sticks, again notched, can be cut to length and used.  Dowels with a finish nail in each end can work.  Sometimes tying the branch down with string or twine to another branch is

Branch Spreaders in place on small apple tree

accomplished.  Weights hung with fishing line to bring small branches down is often a technique that is employed.  Very small new branches just emerging from the trunk can often be directed with a clothes pin clamped onto the trunk.  Some low and larger branches may be tied to a stake in the ground.  Basically anyway you can devise to spread that branch will work.

Remember this training is temporary since the branch will become rigid by mid or late summer and your “training aid” can then be removed.  This training once done will not have to be repeated ever on the same branch.  By bringing those branches down to at least 45 degrees your trees will be stronger and produce much more fruit.

In the spring of 2010 I planted a 4 foot sweet cherry whip in our orchard.  A whip is a tree with a straight trunk and no branches.  Unfortunately I didn’t have my pruners and said I would get it pruned back the next week.  As these things go, by the time I remembered it was too late.  The tree had leafed out and was growing.  During the summer of 2010 it continued to grow tall and got to almost 8 feet. It never developed a single branch and had just a little “tuft” of leaves at the very top part only.  It mostly resembled a skinny Dr Suess Palm tree more than anything else.  In our typical winds it whipped back and forth so much I just knew it would snap off.  I debated whether to risk summer pruning and maybe end all growth and  possibly killing  it or take my chances with the wind.  I decided to wait and it made it through the summer ok.  In early spring 2011 I chopped the trunk off at about 40″ above ground and waited to see what would happen.  The summer of 2011, it grew like a high school teenager, developing a new central leader and about 7 new branches where none were before.  These branches grew from 3 to 5 feet in the summer season.  The leaves were 6″-7″ long and beautiful.  It now looked like a tree on steroids.  While dormant this spring, I pruned the leader and the branches back about 18″ each.  The picture below shows after its final pruning this spring.  The moral of the story?     It’s never too late to prune a tree as long as it is dormant.

 

Close-up of pruned cherry

That is the question.  Many years ago I asked Dr Cummings of the Cornell Fruit Breeding Program about whether or not to prune something.  His answer was: “Not pruning is almost always the wrong thing to do.  Pruning trees is probably the part of gardening that is the least understood and the most confusing for beginners.  There are many methods out there and it is something you almost need to see to understand well.  In addition we instinctively hate to amputate something that we have babied and gotten to grow!  However, leaving it unpruned is not doing yourself or the tree any favors.

Most fruit trees put their energy into the tips and keep growing long.  If these main scaffold branches (the ones that come from the trunk) are not cut back, very little secondary branching will occur.  This secondary branching provides most of the fruit crop and pruning back also allows for the development of a stronger branch.  Unpruned you will end up with a spindly tree that has leaves only at the ends of branches and minimal fruit (generally out of easy reach).

When you cut off the terminal end or last few buds, the growth hormone that was directed to the tip, now has to spread amongst the new end buds and branches are the result. While specifics are beyond the scope of this post, there are a few basic tips:

1.  Any vertical secondary growth from a branch is called a “watersprout”.  Cut these off as they will not fruit and will sap energy from your tree. 

2. Main scaffold branches on very young trees should be cut back by up to 1/3 if you have insufficient secondary branching. 

3. Central leaders should be cut back to encourage new scaffold branches higher on the tree. 

4. Scaffold branches should project radially around the tree and be spaced about 18”-24” above each other. 

A major goal in pruning is to get light to all parts of the tree for proper fruit development. Any suckers from the base should be cut right next to the trunk as these drain energy and provide nothing.

If your tree has not leaved out or is just emerging it is not too late to prune. Many places in the mountains are still cold enough that trees are just budding. The simple rule to remember is winter pruning stimulates growth and summer pruning stops growth.  So while your tree may get a new haircut, it will soon be much fuller and stronger as a result.