Pruning tips

The November 2013 meeting of the Garden Club of PEI welcomed Gary Schneider, who manages MacPhail Woods in Orwell.  He talked about pruning to promote healthy shrubs and trees.  "A good reason to prune is to keep the tree healthy," says Gary.  "I love seeing healthy trees in a healthy setting."  Gary has held pruning workshops for the past 15 years, and he cares about good techniques.

"Some of the best plants start very poorly," says Gary.  "Pruning well can improve plants considerably.  Plants respond well to good pruning. Prune early and prune often."

Smart selection:  Understand the conditions that make individual plants thrive.  Put the right plant in the right place.  Poor plant growth can result from poor nutrients in the soil, or from placing a plant in a location that is not suitable.  Try to put each plant in a location that is closest to its natural state with respect to amount of light, soil composition, and soil moisture.  Some examples:

• Red oaks need a large space because they grow quickly into a big tree.  Don't plant them close to a building.  Don't plant something you know will outgrow the space and think you can prune it back to the size you want.

• Yellow birches planted in the open will develop a crooked stem, and a rounded shape and sprout lots of branches like an apple tree.  In nature, yellow birches grow in a crowded area in dappled shade, and grow tall and slender with few branches because they are reaching towards the sun.

If branches are crowded too closely together, their connection to the main tree stem will be very weak.  You need to cut out some of the crowded branches to allow room for growth and to allow for a firmer bond.  

Gary has a particular dislike for Norway maples and Scots pine.  Both are non-natives, and are poor choices for PEI.  Norway maples are very susceptible to black tar spot and other fungal disease.  Scots pine have very weak branches that break easily.  "I've seen hundreds of Scots pine, and I have yet to see a beautiful one on PEI."

  

Trees respond well to being pruned in the right place.  Pruning at the wrong place will cause trees to respond poorly.  At the base of the branch is a swollen area called the branch collar.  Make your cut just outside that branch collar.  This type of cut will leave a nub sticking out of the main tree stem.  After growing for a few years, the stub will be covered over and healed.  If there is disease in the cut branch, the tree will wall off  the infection if it is pruned properly.  

Do not cut flush with the main tree stem.  A branch collar cut is much smaller in diameter than cutting flush with the tree stem.  A smaller cut will heal faster.  Also, if the cut is not completely straight, the wound will not heal evenly all the way around.  

Poor pruning may cause blight.  Do not lop off the tops of trees because that causes many branches to sprout from the cut top.

Pollarding: 

This is a pollarded plane tree in Geneva, Switzerland.  The branches are cut every year at the same spot to prevent the trees from reaching their full height.  In the summer when they leaf out, they form perfect balls of green leaves.  I'm sure they are not as pretty in the winter, when those monstrous knobby branches are revealed.

The leader:  If the leader (the top branch that points straight up) is cut off, two or more side branches will straighten up and there will be multiple leaders.  With one leader intact, the other branches will flatten out in search of more light.  If the leader dies or is cut off or chewed off by an insect or squirrel, pick the straightest branch and tie it up on the dead leader.  Prune away other competing branches.  

If pruning is done well, it is a flat, clean cut that has a good chance of healing well.  Crowded branches are more likely to crack or split the tree.  A natural break or split will not heal.  

The compressed tissue between two crowded branches is dead.  When the branches get older and heavier, the tree will split.  That is a perfect place for moisture and mould and rot to set in.

Sealing a cut is like putting a dirty bandage on it.  Water will eventually make its way under the sealant, and create a spot for mould and rot to set in. 

Red oaks often have a lot of dead branches.  The tree will respond favourably to having all the dead branches removed.  

Tools:  do not use a chain saw to prune trees.  Do not use anvil pruners (they come together and crush the stem)  A clean cut will close more quickly.

Use bypass shears.  They cut like scissors.    Gary recommends the ARS brand.  They cost about $60 and are made in the US, and are even better than Felco.  When cutting with bypass shears, place the blade against the main stem.  

Pruning saws can't be sharpened, but you can replace the blades. Generally, saws cut on the push stroke.  Japanese blades cut on the pull stroke, and are easy to control. 

sources:  saws:  www.bigbeartools.com has tools that Lee Valley does not carry.  Silky is a good brand.

www.bapequipment.com for ARS bypass shears or corona bypass shears

Garry also carries a sharp knife to smooth out cuts.

When dealing with a crack in a stem, cut in and scrape out loose bark and dead tissue.  The wound will heal faster.  

Use a holster to prevent losing a set of shears or saw.

When cutting, make your first cut away from the final cut, just to take away the weight of the branch and reduce the risk of breakage. You can even prune buds by rubbing them off with your fingers.  

You want branches to be no more than 1/4 to 1/3 the diameter of the main stem.  If the branches are bigger than that, they should be cut off.  

Shrubs - each have different pruning needs.  

• black currants:  cutting off old wood at the bottom will rejuvenate the plant.

• lilacs:  when they flower only at the top, it means the bottom branches are not getting enough light.  Cut off up to 1/3 of old wood. Don't cut off just the top growth. but don't cut off right at ground level either, because that causes a riot of growth.  You want to create dappled shade.

When to prune:  Ideally, the best time to prune is on a beautiful day in February.  But in reality, Gary prunes all year long.  Prune to repair damage any time of the year. If a tree has been damaged, but still has a good root mass, cut it off and it will sprout again and grow quickly. 

Gary suggests that people out for a walk in the woods should take their pruners with them.  Stop and cut off damage as you see it.  That is a great way to improve the forest.

  

Gary invites anyone interested to get involved with plantings in Fernwood, Morrell, and Charlottetown.

For more information about MacPhail Woods, visit www.macphailwoods.org