NABF Newsletter
#5
Feature #10
Montana White Pines
By Jerry Meislik
Pinus flexilis in training 17 years, collected in Colorado.
Height 16 inches
Introduction
Montana is blessed with three species of white pine, the Whitebark,
Limber and Western white pine. I have worked with Limber pines
for about 16 years and find them to make marvelous bonsai.
This is a brief introduction to these trees and their use
as bonsai.
On a hike to Scenic Point in Glacier National Park the trail
winds its way from lush, moist forested woodlands through
sub-alpine areas and finally to treeless alpine areas. At
about 5500 feet of elevation the mix of trees has shifted
from deciduous to conifers. The few scattered trees at that
elevation include Subalpine fir, and Whitebark pine and Douglas
fir.
The most eye-catching sight along the trail is the dramatic
vista of living Whitebark pines scattered in and around numerous
skeletons of dead Whitebarks. The trees are situated in rocky,
nearly soil-less terrain. Many have been killed by the white
pine blister rust, inadvertently introduced about 100 years
ago from White pines imported from Europe.
The European white pines have immunity to the rust since
they co-evolved with the fungus, and although they become
infected they are not killed. American five-needle pines had
no prior exposure to this fungal disease and are attacked
and killed. Throughout the USA the fungus has spread far and
wide and even found its way to these remote elevations in
the Rocky Mountains.
The fungus attacks white pines of all species and once they
are infected they usually succumb to the infection. It is
estimated that 50% or more of these alpine trees are affected.
Infected trees show bulbous swelling of affected branches
as well as needles that turn brown.
White pines vary in their susceptibility to the disease,
and even in areas where nearly all the pines are dead there
are some individuals that appear not to be infected. No known
cure exists for this fungus. Researchers in the Northwest
are identifying resistant trees, and gathering the seed to
establish a disease resistant generation. Over the years it
is hoped that five needle pines will evolve to develop resistance
to the blight and seed of these resistant trees be used to
repopulate the forests.
Whitebark pine – Pinus albicaulis
Pinus albicaulis in Glacier National Park showing living
material on nearly dead trunk.
Whitebark is the west slope variation of the alpine five-needle
pine. They survive at high altitude where almost no other
pines are found, and they tolerate fierce winds, dryness,
poor soil and intense sunlight. They show single or multi-stemmed
growth patterns and are affected by ice and windstorms with
many shattered branches and dead wood features.
Whitebark pine at high elevation hugging the ground to
escape winter’s fury.
The dead and living trees are magnificent specimens defying
the harsh winds and frigid temperatures of this sub alpine
environment. As the trees grow from 5500 feet to tree line,
they show many climactic and genetic modifications. With elevation
the trees become more wind and snow affected and show loss
of branches and bark on their wind-facing sides. The trunks
hug close to the ground hardly venturing over seven or eight
feet in height. This prostrate growth pattern gives them protection
from exposure to wind, and ice, and keeps them under a protective
layer of snow. Trees that grow out of the snow will show damage.
Nearly all the trees have snapped limbs, and bark stripped
off to the heartwood. Even so, they continue to hang on to
life.
Limber Pine – Pinus flexilis
Pinus flexilis purchased in Michigan landscape nursery.
Top three feet removed and jinned. Height24 inches. In training
16 years.
The second member of our white pine family is the Limber
pine, Pinus flexilis. The Limber exists mainly on the eastern
side of the Rocky Mountains while the Whitebark is predominantly
on the western side of the Rockies. Both Limber and Whitebark
occupy much the same environmental niche on dry, sun-exposed
slopes where little else seems to thrive. They tolerate intense
solar radiation, wind desiccation, prolonged drought and very
poor soil. The cones are the major way to distinguish the
species. The Limber pine has a cone that will lay intact for
several years while the Whitebark cone disintegrates at maturity.
Both have 5 yellow to blue-green needles in each cluster.
Pinus flexilis collected in Colorado. Height 36 inches.
In training 13 years.
Birds as well as bears eagerly seek the nutritious pine seeds
of both species. Unfortunately under these extreme growing
conditions a good seed crop may not occur every year. This
failure of the cone crop may have serious deleterious effects
on species dependent on the seed. Some species of bird cache
the seeds for later enjoyment and the uneaten seeds give rise
to clumps of pine trees looking like a many-trunked tree.
Individual Limber and Whitebark pines when growing at elevation
often tend to grow as multi-stemmed trees.
3. Pinus flexilis purchased landscape nursery in Michigan.
In training 16 years. Height 20 inches.
Western White Pine – Pinus monticola
The Western white pine is a much different tree than the Limber
and Whitebark. It is found at much lower elevations and tolerates
moister conditions. It is used as a lumber tree due to its
tall straight trunk and high crown. It competes with Douglas
fir, Hemlock, Western red cedar, cottonwood, and other deciduous
species. It is found close to the 2-3000 foot elevation in
Montana, and can grow to 200 feet in height, with a trunk
diameter of three feet. It has longer needles, a longer cone,
and taller stature than either Limber or Whitebark pines.
Five-needle pines used for bonsai
The needles of the Limber and Whitebark are yellow to blue-green
and not spiky to the touch. The common name of Limber pine
tells you that the branches are very flexible and yet they
accept wiring very well. The Limber and Whitebark grow slowly
but make beautiful bonsai trees.
As with all pines grow them in an open granular soil mix
and keep the roots from staying too wet. A good starting soil
mix is 75% inorganic and 25% organic material. Monticola can
be planted in a 50/50 mix. Otherwise there seems to be no
problems in growing them.
Pinus monticola is a longer-needled tree whose care is similar
but it may be watered a bit more. The soil should never remain
wet or the roots will rot.
All the pines should be kept in full sun for optimum health
and growth.
All the pines can be fertilized with organic or inorganic
fertilizers. Water the trees well before using inorganic fertilizer.
Pests
Pests include aphids, and scale. Aphids can be blasted off
with a strong water spray that can be repeated daily until
the aphids leave.
Scale can be treated with dormant oil at 1 tablespoon per
gallon applied weekly for 3 weeks.
Borers invade sick or stressed tree so watch for sawdust
and small holes in the trunk and branches. Specific treatments
are available for borers.
Do not collect pines infected with blister rust as the infection
may spread to other five-needle pines in your collection.
The intermediate hosts are plants in the Ribes or gooseberry
family. Unfortunately there is no treatment known for this
disease.
Fungal or needle cast diseases can also affect these pines,
and infection is reduced by keeping the trees in open areas
with free air movement.
Repotting
Repotting is usually not necessary for four or five years
in a normally sized container. Growth in a container is slow
for the Limber and Whitebark pines with 3-4 inches of growth
about normal. The Western white pine will grow much faster.
Age
Collected trees are marvelous bonsai with lots of wild branches
and dead wood. Trees from higher elevations can be one hundred
years of age on a one-inch trunk! As with all bonsai use caution
in judging the age of a tree by its appearance. It is very
easy to be way off on the estimate of age.
Limiting factors
There is very limited availability of these trees but I have
found them offered at plant nurseries in the Midwest. Pinus
monticola will be happy into zone 7 but the alpine Limber
and Whitebark will likely only be happy in northern climates,
zone 6 and colder.
Conclusion
Montana has many wonderful native trees. Of these trees the
five-needle pines show adaptability as bonsai and they are
very worthwhile additions to a northern climate bonsai collection.
They are an inspiration even for those living in areas where
they cannot be grown. Their tenacity to survive in extremely
harsh environments as well as their fantastic shapes make
them fabulous trees to emulate in our bonsai.
Whitebark skeleton likely killed by fungus.
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