Pruning
There are several factors to consider before you pull out your hand pruners.
The following information will help you to identify your conifers and determine
when and what to prune.
Is this a conifer?
Before you can begin pruning, you must have a general understanding of how
conifers grow. Conifers can be distinguished from other plants by their needles
and seed-bearing cones. Needle-leafed evergreens fall into two general groups:
Random branching: the branches grow randomly along the trunk. These plants
don't limit their new growth to spring, but grow in spurts throughout the
growing season. Examples include cedar (Cedrus), cypress (Cupressus), dawn
redwood (Metasequoia), redwood (Sequoia), giant sequoia (Sequoiadendron), bald
cypress (Taxodium), and hemlock (Tsuga).
Whorled branching:
The branches radiate out from the trunk in whorls,
much like the spokes of a wheel. These trees produce all of their new growth in
spring. Buds appear at the tips of new shoots, as well as along their length and
at their bases. On pines, the new shoots are called candles, because that's what
they look like until the needles open. Examples include fir (Abies), spruce (Picea),
and pine (Pinus).
When many people hear the word conifer, they think of the familiar conical
shape of a Christmas tree. However, conifers can vary quite a bit in form. The
following terms describe these various forms:
- Globose: globe-like or rounded in general outline
Pendulous: upright or mounding with varying degrees of weeping branches
- Narrow upright: much taller than broad; includes plants referred to as fastigiate, columnar, narrowly pyramidal, or narrowly conical.
- Broad upright: includes all other upright plants that do not fit into the first
three categories
- Prostrate: ground-hugging, carpeting plants without an inclination to grow
upward
- Spreading: wider than tallIrregular: erratic growth pattern
- Culturally altered: pruned or trained into formal or imaginative shapes, such as
high grafts or standards
When should I prune?
Seasonal timing is not as important for conifers as it is for deciduous
tress. This is because most conifer pruning is done for corrective reasons.
Pruning during dormancy is the most common practice and will result in a
vigorous burst of spring growth. However, pruning can be, and should be,
performed immediately when unexpected damage from weather or other causes
occurs.
That being said, there are better times of the year for some pruning
activities, depending on whether the conifer is random-branched or
whorl-branched.
Random-branching: Early spring is best when the spring growth will cover the
pruning wounds. Maintenance pruning, i.e., pruning to keep plants a desired
size, should be performed during the summer.
Whorled-branching: The soft, new shoots, known as candles, should be
pinched or cut before their needles lengthen and harden, usually in mid- to
late-spring.
Pruning in late summer and fall should be avoided. At this time of year, it
is still possible to stimulate new growth. New growth is unlikely to harden
prior to winter and will likely be damaged or killed in the winter cold. Note,
however, minor pruning for decorative purposes will usually not cause harm
during the Christmas season.
What should I prune?
Youre almost ready to get started. But first, you must understand common
pruning terms.
Pinching is one of the easiest cuts to make because it doesnt really
involve cutting. Simply pinch off a terminal bud with your thumb and forefinger.
This will stop the stem from elongating and encourages bushy growth.
Heading means cutting farther back on the shoot than you would for pinching.
In most cases, the lateral bud has already grown a leaf. With hand-held pruners,
you cut right above the leaf. Heading will stimulate the buds just below the
cut, encouraging dense growth.
Shearing is a form of heading. It is customarily used to create a hedge or a
bush with spherical or square form. Because plants chosen for this treatment
typically have many lateral buds close together, you will usually end up cutting
near a bud. Use hand-held shears for this type of pruning. Shearing stimulates
many buds to produce new growth.
Thinning reduces the bulk of a plant with minimal regrowth. With this cut,
you will remove an entire stem or branch. The stem or branch is cut back to its
point of origin on the main stem or to the point where it joins another branch.
Use hand-held pruners or a pruning saw, depending on the branchs thickness.
Finally, youre ready to prune. Heres what you should be pruning:
Leaders
A leader is the vertical stem at the top of the trunk. Most conifers have
dominant leaders, making it generally unnecessary to train your plants
growth. However, if you notice that your young tree has two leaders, you must
prune out one of the leaders to prevent multiple leader growth.
If the central leader has died, you must create a new one. This is
accomplished by bending an uppermost limb into an upright position. Secure the
limb in place with stretchy fabric and a wooden splint. Remove the ties when the
new leader can stand on its own.
Damaged and diseased limbs
Dead, damaged, or diseased limbs can be pruned at any time of the year,
regardless of branching habit. Cut the limb just outside the raised rings at the
base of the limb.
Diseased branches should be pruned by making thinning cuts into healthy wood
below the infected area. Remember, thinning cuts remove branches to their point
of attachment.
Important! Tools should be disinfected between cuts with products such as
Lysol or rubbing alcohol. Note that household bleach is highly corrosive to
metal tools.
Random-branching patterns
Prune in the same manner as a flowering tree or shrub. Use heading cuts to
encourage dense growth, and thinning cuts made close to the trunk to maintain
the trees shape. New limbs can be established by using header cuts in older,
foliage-bearing wood.
Important! Heading cuts will only sprout new branches if the remaining branch
still has needles growing on it.
Whorl-branching patterns
Instead of making heading cuts, use your thumb and forefinger to pinch off the
candles while theyre still soft. This will maintain plant size and produce
denser growth. Be careful that you dont cut into older wood below the candle
because these conifers have few or no dormant buds that can become new limbs.
Important! You wont want to make thinning cuts. This would produce a dead snag,
not new growth. The only exception is spruce trees: They have side buds that
will sprout if trimmed back to the previous years growth.
