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Re: Pruning season

Marina & Anthony Green wrote:
> 
> Dear all,
> 
> Now for a very beginner's type problem:
> There seem to be so many different opinions about when the best time to
> prune things is. Now that the summer's heat has gone and the growing
> season is back, I would like to change the question around and ask what
> huge drawbacks there might be to pruning back hard now on leggy shrubs
> like Nerium Oleander, Pittosporum Tobira, Tamarisk sp. and Lantana sp.
> With so much contradictory info to choose from, I've always been much
> too shy of cutting back and now they're all getting pretty ropey!
> Also, does anyone have a successfully pruned Mirica sp.? - every time
> I've pruned it, the cut area seems to go brown and die back!
> 
 Anthony

I wonder if the Sunset Pruning Book is still around. My copy dates from
1983, but there could be a much later edition. This one of the most
useful books on pruning I have come across, with the answers for almost
any species you can think of.

With shrubs grown for their flowers it is usual to prune them as the
last flowers fade and then they will have most of a year to grow their
new flowering wood, but those grown mostly for foliage, like
pittosporum, can also be pruned at other times of year. However, it is
always best to do it just before you expect a new spurt of growth,
otherwise you may get dieback. The other thing which can cause dieback
in some more fussy plants is just cutting stems anywhere and not to a
joint (node) where there is a growth bud present. On some groups however
(notably the Proteaceae and many conifers) there may not be live growth-
buds on bare stems, but only where leaves are still present, and if you
cut into bare wood the branch will die. If you are not sure, it pays to
cut one stem first and see if there is new growth from the cut before
doing the whole plant. However, even plants which will not grow from
bare wood can be thinned by cutting whole branches back right to their
base.

Most plants with a clumped style of growth, which regularly produce new
shoots from ground level (such as Oleanders), can be rejuvenated by
cutting out all the old and leggy stems so young new shoots have space
to grow.

Tamarisks can be allowed to grow into trees, but flower better and
certainly need less space if kept as shrubs by pruning to the ground in
early spring or late winter. They will then grow rapidly and produce
huge flower plumes during summer and autumn.

Lantanas flower best on new wood and should be cut back severely to just
a main framework every spring.

You do not say whether your Myrica is a deciduous type or an evergreen,
but both should only be pruned in late winter or early spring. The
deciduous Bayberry should have old stems thinned out from time to time
and can be stopped from spreading by digging out new shoots on the
outside of the clump. The evergreen kinds do not need regular pruning,
but can be tidied up if necessary. Sunset suggest making them into small
trees by thinning the crown and cutting off the lower branches  to leave
a definite trunk.

One or two useful tips:-
(1) The harder you cut the more vigorous the new growth.
(2)Be very careful WHERE you cut. If you do not cut to where there is a
side branch or a live growth bud, the stem will die back to the next
node (joint) as it will have no leaf to draw sap up.
(3) If you have a stem or side branch you do not want, remove it
completely WITHOUT LAVING A STUB. If you do (as many amateurs seem to)
leave such a stub, one of two things will happen. If the stub is too
short to include a growth bud it will die back to its base and may
sometimes let rot into the trunk. If it is a bit longer and has some
growth buds it will produce a mass of unwanted new shoots.
(4) having said that, you do not, in fact want to cut side branches off
quite flush with the trunk, as they have a special sealing layer called
the collar right at the base. In some woody plants the collar shows on
the outside as a noticeable thickening about half an inch wide right at
the base of the side branch, but in others it is not so obvious. So
leave any visible collar, or if you can't be sure, half an inch (no
more) of the base of the stem you are removing. 

This is especially important when cutting large branches and you need to
be careful also with them you do not get tearing on the bottom side of
the cut. The best way to handle this is first to cut off the main, heavy
part of the brench, leaving a stub about a foot long, and then carefully
remove the rest after cutting through the bark on the underside.

Moira

-- 
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata, New Zealand
"Old" is 10 years older than I am.
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