There are many ways that oaks adapt to the
landscape but the form most associated with oaks that grow on the rolling
hillsides and open areas of the landscape is embodied by rounded foliage
silhouettes grounded by a buttressing trunk that splits into several vertical
and slanting leaders. These trunks, in turn, meander up and around, casting
branches every which way to form sub-crowns in the informal umbrellalike
shape. Oaks are usually broader than they are tall and are marked with a
fountainlike upward and outward branching theme with the tips drooping
slightly at the exterior edges.
Unlike pines which are typically styled with
defined branches and pads, oak branching takes off more randomly with riotous.
Heavy interior branch movement, eventually reducing down to fine twigs at the
edges of the silhouette.
The beautiful movement in a mature tree in
the landscape is a result of years and years of multiple shoots extending,
competing for sun, crowding out weaker shoots, being damaged in windstorms and
by insects, wildlife or pathogens. Some just die out and others fill the void
in the canopy vacated by those dead shoots and branches.
All of those shoots start out straight. It
is the incremental nature of growth over time that yields the wild curves in
trunk and branch. In Bonsai, we try to compress those years of movement by
wiring those straight shoots with exaggerated curves. When wiring a
bonsai branch, the most important section is the first three to five inches.
Growth longer than that can be allowed to grow straight to thicken up the
interior curves and help them set faster. Bending creates a succession of arcs
from which the next shoots will come. This series of arcs, as opposed to
straight lines, creates a more natural feel to the tree.
As much as possible, working with new shoots
yields the best results. They can be manipulated freely without having to fight
an old leggy branch with dead patches and aging, reluctant latent buds. Young shoots
and branches devote most of their energy to growth and expansion. Older
branches lack the same dynamic energy for growth as they must allocate
resources to maintain heartwood, sapwood and dead stretches due to shari and
For an oak, the phyllotaxy, or the arrangement of leaves
on a shoot, is five to two. This
means that between one leaf and the next one in the same position on the shoot there
are five intervening leaves rotating twice around the shoot at about 144°
Trivia? Yes. When we bend curves in the oak shoot, we can use this growing feature to add randomness to the branch angles
and get that meandering oak characteristic.
the fall growth to mature
and store energy in the vascular system of the tree
over winter, the tree can be
cut back hard in mid-January on both deciduous and evergreen oaks to the point where new shoots are desired. Sometimes, even on an evergreen that
means going back to bare wood, leaving no green growth left on the branch.
Scary stuff! But forge on! Remember to seal the large cuts with cut paste. To develop
branches from scratch on evergreen oaks, try the following procedure.
Year 1. After the
above cut back in January, new shoots pop on native oaks at and just behind the
cut appearing in late February-early March as the days lengthen and it begins
to warm up. New growth is allowed to harden (they become less succulent, turn
darker in color and get stiffer, waxier leaves) usually by mid to late April.
(Cork oaks are usually about four to five weeks later). New shoots are wired
out four to five inches or so in an inclining slope, bending the shoot mostly
up and out and up and out, then a little side to side movement in this same
section. The shoot tips
should be allowed to grow unrestricted for the remainder of the year but
remember to remove the wire when it starts biting in, usually in six to eight
Year 2. Next January
cut-back, leaving three to four inches of the new curved branch area. Repeat
last year’s process; cut, harden, wire, remove wire, grow. But this time there
may be lots of shoots on the three to four inches. Wire three of the shoots
(backside, front side, and top) in the same manner as Year 1.
Year 3. Next January, the three secondary shoots from last year are each cut to two to three
inches, wired in April after hardening, then choose six shoots (two on each of
the three shoots from last year) to wire. Again, remove
the wire after the bends are set and, at this time, cut back each of the six shaped shoots to two
to three inches. When new shoots come out and harden, wire two shoots and let
the branch set in position yielding 12 tertiary shoots. Remove the wire when the bends are set and leave until next January’s cut-back.
Year 4+. From then
on refine the branches by cutting back to two to three leaves in January, and each time there-after, as the shoot
elongates and before
it hardens, leaving
a side shoot and leader.
Wiring and big cuts won’t be required other than to occasionally adjust the styling or thin over crowded areas. By
now, the branch will be well on the
path to having that nice ramified oak appearance with good transitional taper.
Defoliation every year or two, can help reduce leaf size after growth
hardens, up to about August 1st. Be cautious thereafter. Only defoliate on healthy trees!!
Occasionally, allow a random interior branch
to grow outside
the canopy without
wiring. When it gets past the established silhouette, strip the leaves
up to that silhouette and allow it to then run unobstructed. This sacrifice
branch will give better transitional
taper for the tree where needed,
as well as create mature
bark, especially with cork oaks. Young, rampant growth is the key to
getting good bark. Eliminate the branch when it has accomplished its job and
before it weakens the area around it.
We want those
interior branches to remain strong because, no matter what we do, the
tree will eventually expand and become leggy. Then we need those branches to
cut back to and restart the building process.
Who said that Bonsai is not perpetual fun?
maintenance. When the desired branch shape is achieved, pinch back the
extending shoots, as they open, at the edges of the branch silhouette. Allow
shoots to fully extend if you need to fill a hole in the branch shape.
Deciduous oaks can be cut back in January
and thereafter to two to three leaves in May after hardening and maybe once
again if it’s extremely strong. Total defoliation of deciduous oaks late in the
year (August forward) is very risky and hard on them, using up a lot of the
energy reserves of the tree. They can sometimes shut down and wait until the
following year to produce new shoots, or throw out a few shoots while cutting
off and killing some branches you need. However, after leaf hardening, early
defoliation thru June will reduce leaf
size and if paired with cutback can generate new shoots as well. If you can’t defoliate, cutting back and
thinning the upper section of each branch crown will allow light below,
will save interior
leaves from dropping
and shoots from weakening.
Keeping them super healthy
and active is important.
Bonsai Care and Development
Operations and Purpose
Trunk Development Primary Branches
Secondary I Tertiary
Branches Twigs and Foliage Maintenance
back to earlier stage when necessary to solve problems)
- Sun I Temp I Wind – adjust growth cycle – damage control
- Water –
maintain proper hydration
- Soil I Pot- size and composition / volume and shape
interval – speed-up / slow down growth – refresh
growth regulation – amending for health
treat and/or get ahead of Insect and fungus
Branches or Leaves Pinching- shorten internodes – maintain
shape – bifurcate Pruning –
determining shape – bifurcate
Thinning – Open cramped areas – save inner branches
Defoliation – reduce leaf size
- Wiring – Shape
Branch / Design
Dec. 21 Winter Solstice
Mar. 21 Vernal Equinox
June 21 Summer Solstice
Sep. 21 Autumnal Equinox
Intensity of Sun • Temp
Perform Operations at the Appropriate Times in the Plant’s Growth Cycle
· Apical Growth
Cytokinin – Lateral Growth
Pinch/ Prune Hint
2 –Leave 2 buds / leaves – a leader and a side shoot
Bend in toward main, then bend out toward sun.
This handout was prepared by John Thompson (2019)