NEIGHBORHOOD GARDEN FOR DECEMBER 8, 2007
PINE WILT (PART 2: REPLACEMENT TREES)
BY GEORGE EDGAR
Over the past
20 years PINE WILT has killed
so many Scots
or SCOTCH PINE
sylvestris) trees in the Midwest that Extension Specialists and arborists in
many Midwest states no longer recommend planting this once popular
species as a landscape or windbreak tree. Some experts even predict that
we will not have any Scots
pine trees in eastern and central Nebraska within 5 to 10
years. No cure has been found so far. High value trees can be protected
with a series of trunk injections of Greyhound (abamectin is the active
ingredient). This is a preventative treatment and very expensive.
information for this article I looked at many sources and found the most
useful information from the Nebraska Statewide Arboretum. Justin
Evertson of NSA has a good article on Less Common Conifers. He
says, Throughout much of the Great Plains, just a handful of species
make up the majority of evergreens planted. This lack of diversity is
starting to be a real problem in areas where diseases are decimating
both Scots or Scotch
pine and Austrian
Pine. (Botanical Bits February 2004). He also recommends
that we plant native trees that know how to survive in Nebraska.
listed below are from an NSA article, GreatPlants Gardener 2005 Plant
Descriptions for the Eastern Great Plains and includes trees that
Eastern Red (Juniperus virginiana) - an
upright evergreen that tolerates wide range of soils and climate;
Canaerti' is a great cultivar with tufted foliage; 'Taylor ' is an
outstanding GreatPlants selection from central Nebraska noted for its
narrow, upright habit (Height=40-50, Spread=8-20)
one of the noblest conifers; unique cones are adorned with tails;
not as drought tolerant as spruce; fails on dry, poor soils; injured by
high winds. (Height=50 ft.)
(Abies balsamea) nice
fragrance; 'Canaan' is a variety that should be tried more.
(Abies concolor) one of
the most beautiful evergreens; bright blue new growth eventually makes
for soft, blue-green needles; should be planted more. (Height=30-50,
Fir, Fraser (Abies
fraseri) very similar to
balsam fir, not quite as hardy, needs consistent moisture.
(Height=40-60) (Very slow growing and hard to grow in Nebraska.)
Fir, Korean (Abies
koreana) deep purple cones
amid short, green needles with white banding underneath; heat tolerant,
but prefers cooler areas.
Fir, Nikko (Abies
homolepis) glossy, green,
1 needles on a fairly narrow tree holding its pyramidal shape in old
age; fairly wind tolerant, except in dry, winter winds.
(Pinus heldreichii) var.
leucodermis similar to Austrian pine; worth a look.
extremely cold hardy; gnarly growth habit. (height=30-40)
Pine, Lacebark (Pinus
mottled bark; avoid windy, exposed sites. (Height=40-50)
Pine, Limber (Pinus
flexilis) native to
Kimball county; very flexible branches are plume-like with twisted
blue-green needles; for well-drained, dry soils only. (Vanderwolf is a
good cultivar/variety and readily available. (Height=40,
Pine, Ponderosa (Pinus
ponderosa) reliable native
with long needles and beautiful bark; for well-drained dry soils; avoid
over watering. (Height=50-60)
Pine, Red (Pinus
reddish bark; very cold hardy and drought tolerant.
(Pinus strobus) tolerates
wetter conditions than most pines; nice long, soft needles. Rapid
growing, pyramidal shaped when young, becoming umbrella-shaped with age.
Spruce, Black Hills
(Picea glauca var. densata)
a variety of White Spruce.
Nice alternative to blue spruce; short, dark green needles; likes to be
kept moist; tolerates tough sites and conditions; extremely hardy.
Spruce, Norway (Picea
abies) beautiful weeping
habit and attractive long cones on this durable tree from Europe;
dislikes windy, dry sites. (Height=50-70, Spread=30-40)
(Picea omorika) arching,
ballerina effect on branches; deep green with white undersides;
adaptable; (Height=50-60, Spread=20-30)
more familiar trees that you should look at include:
Colorado Blue (Picea pungens var. glauca)
a majestic tree that is used quite often as a specimen tree, but
beautiful. (Height=60, Spread=25)
Colorado (Picea pungens) - Similar
habit as Colorado Blue Spruce but
having deep green foliage. (Height=60, Spread=25)
glauca) - Alberta Spruce is another variety as is the Black Hills Spruce. Likes full sun, well drained soil, medium to dry
moisture. (Height=40-60, Spread=10-20)
For more information about trees and shrubs, you can reach the Nebraska
Statewide Arboretum on the internet at http://arboretum.unl.edu.
At this web site you can get more information on the trees listed. They
also have links to colored pictures of the trees mentioned. I want to
thank Justin Evertson for permission to use his articles in this series.
You can also
contact your County Extension Educator or go on line to www.ianrpubs.unl.edu. On the left hand side
you can type in the name of a disease or the name of a tree then click
on search. A list of publications will appear. You can read those you
want and/or download them to your computer or print them for your files.
Or you can go
This is the web sight for the Nebraska Forestry Service which is a
division of the University of Nebraska-Lincoln. In the upper left hand
corner in the search box type in pine wilt or the name of the tree
you want information about. A list of publications will appear. You can
read those you want and/or download them to your computer or print them
for your files.
In Part III, I
will give suggestions on how to go about selecting a new tree for your
landscape or a replacement for your Scots
pine. I will also give tips on how to plant the tree