It is not actually the pruning in the winter
that causes the water sprouts. It's the way the tree is being
pruned. Pruning for training purposes is usually done in spring
and summer and any water sprouts that exist can be pruned out at the same
time. This practice will cause you to have to do less dormant pruning,
but all of your thinning out should be done when the tree is dormant.
Here's a section from one of
the guides I use to train our staff and is found on the internet at
http://www.eap.mcgill.ca/CPTFP_7.htm.
All pruning cuts can be classified in two major categories,
termed heading back and thinning out. The
differences in tree growth responses to heading back versus thinning out can
be traced to their differential effects on the pattern of growth regulator
movement in the pruned branch. In thinning out, an entire shoot or branch is
removed at its junction with a lateral or scaffold branch, or with the trunk.
In contrast, heading back involves removing only a portion of a branch and
interrupting the normal movement of growth regulators in the remaining branch
section. The more severe the heading back in 1- year old wood,
the stronger the vegetative growth response from buds just below the
cut. Heading back in older wood results in
the conversion of potentially fruitful spurs to vigorous, non-fruitful
vegetative shoots. The response to heading back can vary depending on
several factors. Naturally vigorous cultivars with strong, upright growth,
such as 'Delicious', exhibit a greater growth response to heading back than
less vigorous cultivars. Trees of any cultivar in high vigor produce strong
vegetative growth when headed back. Unlike upright branches, heading back
comparable horizontal branches results in little increase in total vegetative
growth over comparably oriented unpruned branches. However, the heading
back cut stimulates more vigorous growth from buds near the cut,
proportionately reducing branch development along the horizontal limb. The
presence of a heavy crop can reduce or even eliminate the usual growth
response to heading back. In contrast to heading back, thinning out cuts are
not accompanied by the dramatic changes in growth pattern favoring development
of vigorous vegetative growth. Because normal growth-regulator movement in the
intact parts of the branch remains largely uninterrupted, shoot growth and
stem thickening proceed normally.
If you already have an issue with water sprouts, it is
best to get rid of them with summer pruning. August is typically the
best time of the summer, depending on your climate zone. But if you are
having water sprout problems, it is primarily caused from improper dormant
pruning. Hope this helps.
I have picked up from some letters lately that pruing some
apples in the winter encouraged tons of water sprouts and that some
varieties are better pruned in the summer to avoid that. Is that
true? What varities are better summer-pruned and when is a good time
to do that? Jerry in southern Indiana
AOL now offers free email to everyone. Find out more about what's free from
AOL at AOL.com.