Fruit Tree Care

March is a good time for pruning fruit trees – the trees are dormant, the leaves have been
put to use in compost piles or bins, apples have been eaten, canned, given away or left for
squirrels, so for these reasons we can now see if any branches should be removed. The
main question is … do I need to prune?
The normal rules of pruning apply – the three “D”s: branches should be removed if they
are dead, diseased, or damaged, and preferably never remove more than 20% of the
branches, otherwise water sprouts, (aka water shoots) will appear and grow quickly and
vertically from dormant buds – and will reduce exposure to sunshine and interfere with
other branches. I learned many years ago how to prune apple trees, but alas I did not
realize the method my father gave me applied principally to commercial orchards – so
beware of well-intentioned but incomplete advice – consult an I.S.A. certified arborist if
in doubt. Pruning is not essential, but allows more light to penetrate the canopy, and
increases the size of the fruit: if there’s no fruit, perhaps you need another tree for
pollination. Also, in the late summer, remove smaller fruit to allow the remainder to
develop better.
Have a look at the small orchard on Summit Street to see how the trees have done there
since they were planted in 2012. The seven apples have done better than the four pear
trees. The superb example of an old pear tree over twenty feet high is on the 200 block of
Superior Avenue – it may be more than 50 years old: owners’ advice? – water deeply.
Fertilizing: as with other plants, tree fertilizing should be done cautiously avoiding too
much nitrogen, and if the surrounding garden is occasionally fertilized, your tree should
be fine. For new fruit shrub and trees, have a look at the University of Saskatchewan web
page, it’s worth it.
Glynn Wright.

Winter Colour in trees

2016

We have a variety of grey coloured deciduous trees and shrubs in our winter, and these form a background to our landscape, but evergreens and other trees provide highlights in our yards and boulevards. Part of the planning process for the upcoming growing season could be to see how to add colour to our winter views. Bright coloured dogwood for instance can bring raise one’s spirits if certain varieties are chosen: the two often used are the red or scarlet stemmed dogwood, or the greenish-yellow dogwood: no matter which type you choose, the brightest colour comes from the young twigs, rather than the grey and scarred old stems – prune them off.
Tree bark similarly provides most colour from the younger branches. Older varieties bear the scars of life, but this appearance is not all bad news: the corrugations in the bark provide refuge for “bugs”, both good and bad, and therefore provide a smorgasbord for over-wintering birds. As an aside, I recently read that many birds that are fed at bird-feeders will survive even if their bird-feeding tables are without seeds … and I see that smaller birds flock to shelled black-oil sunflower seeds but eschew many of the mixed grains including red milo that is cheaper … probably only pigeons will eat milo. Another advantage of shelled sunflower is that there is no debris to cleanup in the spring.
In Calgary, trees with fabulously coloured bark include mountain ash, amur cherry, birch, and Japanese tree lilac. Unfortunately the first two suffer from winter sunscald often on the south or south-west side of their trunk. The lentil-shaped marks (usually horizontal, and very visible on white-barked birches) on tree bark are lenticels. Apart from being attractive decorations, more critically, they provide for gas exchange between the atmosphere and the inner tissue, essential to the health of the tree. They form by extrusions from the cork layer of the tree stem and these protrusions often grow larger with increasing circumference of the stem. Check out your neighbours’ trees!