Excerpts from pages 3, 11 and 12 of What's Coming Up
The 1/3 Pruning Rule,
Breaking the 1/3 pruning rule and
Barbering a barberry
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First: Pruning's one third
We can pretty safely reduce total leaf count or total root tip
count by one third if we then pamper the remainder with a close eye
out for any trouble plus steady water and fertilizer.
Breaking the 1/3 pruning
It's a guide, not a law. Healthy, fast growing species give us
lots of leeway to deviate.
We break it all the time when we cut butterfly bush
(Buddleia) to the ground every year and cut tree-form
weeping mulberries (Morus species), Catalpas,
pussy willows (Salix caprea and other willows such as
dappled willow), smoke bush (Cotinus species), roses and
panicle hydrangeas (H. paniculata) to nubs-on-a-stick each
April. We abide by it in roundabout way as we often allow a 3-4
year interval between cuts when we chop summer-blooming spirea
(Spiraea japonica, S.bumalda, etc.) or barberry
to the ground.
Deciduous plants and broadleaf evergreens have an advantage over
needled junipers, arborvitaes, pines and spruces after leaf loss.
They can use their reserves to develop greenery from dormant buds,
more quickly re-establishing a healthy wood-to-leaf ratio. Chop a
barberry like this (right) to the ground and every stub
will develop new shoots from dormant buds. (It can also then be
this size for the year without another cut, with an outline that's
softer around the edges than this one created by shearing. See the
'Rosy Glow' further along for that softer look.)
Timing makes a difference
Plant health, hardness of cut and our timing make a difference.
Early in spring, plants' internal chemistry and external stimuli
combine for the year's best growth. Choose a healthy plant, cut it
hard in spring so its bud:wood ratio is high, and new shoots may
each grow several feet in their first year. Wait until summer to
chop it back or cut it only by half so it must start anew with a
great deal of leafless wood, and the comeback will be less
Cut back barberry?
...regarding Barberry. You said it could be
cut back to the ground. Does this mean any species and how long
will it take to come back? I have miniature or pygmy bushes
that unfortunately, I have not pruned as much or regularly as I
should have and they have gotten larger than I planned. - S.W.
Any barberry species can be cut back right to the ground. If the
plant is healthy and in a good site it'll grow a lot more than you
expect right away that first year... depends on the variety. The
full sized ones usually grow to about three feet tall the first
year... The pygmy types pop back up to be six to 18 inches... If
you cut them back to stubs before they push out any of their
preplanned growth, they will form new growth from dormant
To save our hands and arms from thorns as we cut back a
barberry, we wrap a bungee strap around it to cinch the branches in
tight, or tie a thick cord or rope around them and pull that tight.
Then we use loppers to cut them all off just above ground level.
The branches come away in one bundle that we can carry easily,
painlessly to the yard waste area. (This is illustrated in Barberry
We try not to complain. Mostly we work with Berberis
thunbergii, which as barberries go is not all that dangerous.
Others have much more puncture power.
One reason to cut a barberry to the ground every 3 or 4 years:
As they age, twigs become brittle and are shed. They drop into the
garden and end up embedded in our hands. When we cut the shrubs
hard so they are all-new every few years, there are no brittle old
Another reason to cut barberry is to enjoy more colorful
foliage. People often say of variety 'Rosy Glow' (right),
"It never showed much pink!" That's usually because the gardener
repeatedly sheared it -- many do this after they realize the shrub
is larger than expected. The newest foliage has the best color, so
the yard waste bin got the color you wanted to see! To sidestep
this problem, cut it back in early spring to two feet shorter than
the finished height you want, then let it grow all year.
Think you have it bad, handling Berberis thunbergii,
the Japanese barberry species (below, left) that includes
'Rosy Glow,' 'Crimson Pygmy', and 'Gold Nugget'? Maybe you don't
know about all the other barberries, some with very long, stiff
spines (below, right)...
...or spines on leaf edges as well as on twigs.
When those spiny leaves drop to the
ground and dry -- youch! Even evergreen barberries shed leaves
periodically, so there is finger-piercing material on the ground
around these plants even if you keep them cut every few years to
prevent brittle branch fall-out.
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