Pruning Trees

March 30a 2013 (2) There are plenty of reasons to prune.  The branch of a tree, shrub, or rose may be dead, and need removal.  It may be growing across the sidewalk, and need some heading back.  An old lilac may be blooming only at the top, 15 feet above ground, and need rejuvenation.  Branches of shrubs that cross over each other, and rub off the bark is an invitation to disease or insect damage.  Intact bark protects the life inside.  Pruning can help keep woody plants vigorous, healthy, and beautiful.

Plants maintained as hedges require regular pruning. The lindens at the shop form a hedge the body of which is above ground.  The branches at ground level have been removed over the years so people may walk underneath them.  Regular pruning of the trees promotes a good framework of branches that represent the desired shape.  These lindens were overdue.  Though I am a serviceable pruner of shrubs and roses, this job asks for an expert.  Someone who knows how to safely navigate high above the ground, and someone who understands the consequences of each cut, deliberately pruning in anticipation of a desired result.
pruning-the-lindens.jpgTrees that are trained as an overhead hedge are pruned with the idea of encouraging lateral growth.  Anyone who has ever topped a shrub knows that the plant responds to a single cut with multiple sprouting shoots.  This results in a dense pattern of twigs on top, which blocks the light to the interior.  Every branch of a plant needs light.  Shrubs that are repeatedly cut back so every branch is the same length eventually decline on the interior, and will need more drastic pruning to restore them to health from the inside out.

Pruning trees in late winter means there will only be a short time before growth resumes, and the healing of the cuts can begin. Another reason to prune now is that the cuts will stimulate growth at a time of year when new growth is expected.  Trees actually stop growing and begin to go dormant in late summer.  This is part of the process by which they are eventually able to  go totally dormant, and endure the winter without injury.  I do not like to prune seriously at the end of the summer or in the fall-the plants should be going to sleep.  Not shocked into growth.  Pruning these trees the end of March will encourage dormant buds to flush out.

on-the-roof.jpgThe roof next to the trees turned out to be handy.  This perch, and a long and very sharp pole pruner, enabled Jack Richardson, owner of Guardian Tree Experts, to trim the inside flat sides of the lindens.


When the trees leaf out, those leaves will make a giant rectangle above ground.  They will represent this better next year than they will this year. Pruning that waits too long means more time will be needed for the trees to grow in how you envision.  The trees were originally planted far enough away from the building so the shape would be easy to see.  This also permits light to wash that dark wall.  The relationship of the sun to the shade is a feature of this space in the summer.

pruning-trees.jpgThe big cuts make it easy to understand the concept of lateral growth.  The thick branches are pruned back to a smaller branch which is already growing in the proper plane.  The smaller branch will benefit from the growth energy in the tree directed its way.  Dormant buds at this point will emerge, and grow into the space around the larger branch.

hedging-the-lindens.jpgThe overall vertical plane has been reestablished.  In a year, a decision can be made about whether to prune again, or wait until the following year.  That said, frequent and less drastic pruning makes for a quicker recovery time.  Regular pruning from the beginning helps to create a strong and healthy structure.

dying-tree.jpgThe ultimate pruning means taking a tree down to the ground.  This maple, suffering from girdling roots and severe injury from lightning has become a hazard.  The large left lateral branch is at such a near horizontal angle that the branch has begun to split.  The original wound never really healed, and now the tree has begun to rot.  No one could foresee the exact moment that this big tree will give way, but all of the signs are there.  This tree needs to come down.

taking-down-a-maple.jpgNorway maples are especially prone to girdling roots.  A root that encircles a tree trunk can eventually grow enough to strangle the tree.  At a certain point, the pruning of the offending root is too late to make a difference.  Every one of the maples on my property had significant girdling roots when I moved there.  Knowing that this tree would eventually die, I planted other trees around it.  The loss of a large tree can be devastating to the community planted underneath it.  This maple had been in serious decline for many years.  Very little remained of its crown.

There are 5 trees that were planted fairly close to the maple-2 magnolias, and 3 parrotias. Those trees had been in ground and growing long enough for their upper branches to reach the height of the lower branches of the maple. The time was right to take the maple down. The 5 remaining trees will prosper from the light, space, and less competition for water. They should grow very fast now; their filtered shade will be just what the garden underneath them will need.  Guardian Tree Experts in Ann Arbor-they do first rate work.  The trees are ready for a little spring weather.

Let’s Talk Pruning

Were I ever to be appointed garden czar, I would require a certificate in proper pruning before I would ever sell a pair of pruners to anyone interested in growing plants.  OK, just kidding. This is the USA, and everyone’s freedom to prune as they see fit is guarenteed by the constitution. But I do see lots of evidence of uninformed pruning, so I thought it might be a good idea to offer some pointers; does this sound more friendly?

 Plants have a natural habit of growth.  Anyone interested in plant habit has no end of sources to research this subject.  Plant tags give this information at no extra cost.  Where people get into trouble is placing a plant they like in the wrong place. Shrubs that mature at 8′ by 8′ have no business being planted next to the sidewalk.  Planting two giant shrubs closely on either side of a walk that with true and brave pruning that results in an arch overhead-brilliant. The single shrub placed properly for the pot size, and not the mature size, will grow into a pruning nightmare. The pruning required to correct a mistake will make you look like a dictator-not a gardener.

The appearance of a large growing shrub planted in a too small a space, that has been pruned back to fit that arbitrary space, will offend the eye.  Pruning is about giving every branch light and air; pruning is about keeping a shrub green and thriving top to bottom.  Pruning is not about wedging a plant into a space that nature never intended. Any plant, given the time, space and care to mature to its finest form-glorious. 

        Woody flowering shrubs have a specific period of bloom-nothing tricky here.  Prune promptly after the bloom. I am talking forsythia, lilac, rhodendron, roses, and the like. Every pruning cut encourages a plant to send out multiple shoots from the cut. The best time of the year to see how one cut produces multiple shoots is right now.  There is not much foliage yet to obscure how a plant is responding to your pruning.  Get out in your garden, and study the pattern of the sticks-the results of your pruning. 

 Woody deciduous shrubs have a natural habit that provides no end of clues about how to properly prune. Euonymus compactus alata-dwarf burning bush, grows strongly to 8 feet high, and as wide. The yews pictured above are some form of taxus densiformis.  Their natural form is loose and sprawly. Should you be pruning in a box or ball shape 4 by 4 feet-there is conflict sure to come. Each cut brings forth a proliferation of new growth.  Sooner or later the growth on the skin of this yew will be so dense, all the foliage on the interior will languish and finally die from lack of light.  Though closely trimmed yews can be very pretty, I try to cut a few light holes in various spots-I call this swiss-cheesing the plant.  Let some light reach the interior.  These yews are placed such that should they get bigger and bigger, they will not obstruct a walk. Yews cut back to bare wood will sprout again-but the recovery will be slow. 

 Once hydrangea buds show green, I prune.  Annabelle I never prune hard.  Like a tea rose, a hard pruned Annabelle will reward you with fewer, and even more giant ball shaped blooms.  As this shrub has weak stems, and goes over in the first hard rain after blooming-there is no need to exascerbate its shortcomings. Those giant balls on the ground in the mud-not so satisfying. Prune lightly, and all over.  Every branch; take the time to cut them so they have a little sun and air space all their own. Your patience will be rewarded with lots of a little bit smaller blooms-making the entire shrub more weather resistant. 

There are those yards where I see everything pruned into a green meatballs, green boxes, mushrooms, or rectangles. Or some lopsided version of the above. Should it be your idea to prune towards a geometric shape, get out the level lines and do it right.  Imposing mathematical geometry on a natural form needs to be done with knowledge aforethought.  And purpose. And most importantly-the right plant. Some plants respond and thrive in response to this treatment.  Other plants respond by throwing a skin of leaves-the interior branches go dead from lack of light.  Boxwood tolerates this type of treatment; other plants-not so much.

 No plant needs a heavy hand.  Heavy hands come from those non-gardening people who have been given the chore to get the yard in shape.  Heavy hands given a sharp instrument-not always the best result.  I think about every cut.  I cut with a natural form in mind.  I cut to help provide air, light, and densely natural shape. There are those for whom this statement is an utter bore-but if you garden with a passion, you know exactly what I mean.  

Prune with sharp and clean clips.  It is no good to spread communicable trouble around with dirty and infected clips.  Clip what needs be clipped-pass on what does not. Stop the pruning in midstream, and consult-should you have any questions.  Poor pruning is not the end of the world; plants have an incredibly strong instinct to survive.  They will endure, and possibly outlast you. But the season comes but once a year. 

Stay tuned.  More on proper pruning to come.