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Shoestring Acacia,
Acacia stenophylla,
 combines two qualities
that are rare among
popular desert landscape trees:
columnar (upright
growth) structure and
evergreen foliage. This
Australian native was
introduced to the desert
southwest decades ago
but gained wide
popularity only in the
last 10 to 15 years.
Shoestring Acacia is
reasonably fast growing
maturing to a height of
20 to 40 feet with a 15
to 20 foot spread. The
trees are moderately
drought tolerant but
cannot be naturalized to
subsist on the annual
rainfall in the desert
southwest. Shoestring
Acacia
grows well in full sun
or partial shade and is
cold hardy to about 18
F. In Australia, where
it is used as lumber and
a food source for
Aborigines, it is found
growing at the edges of
rivers and will tolerate
periodic flooding and
heavy clay soils. The
tendency to grow along
streams may explain two
of its Australian common
names, Native Willow
and River Cooba (Cooba
is the Australian common
name for Acacia
salicina). Best growth
is achieved in well
drained soil and regular
deep irrigation.
Cream to yellow colored,
ball-shaped flowers, in
small clusters, (3 to 6
flowers/cluster) occur
throughout the year with
the majority produced in
spring. Flowers mature
rapidly to pods that
resemble a string of
pale green beads with
pods constricted between
each seed. Leaves (or
phyllodes) are long and
narrow approximately 1/4
to 1/2" wide and up to
12" long. Leaves are
pale grayish green and
are generally straight
but can be slightly
curved or twisted.
Stenophylla's do produce
some leaf, flower and
pod litter.
The bark of maturing
trees is rough, deeply
textured and dark brown
giving it a sharp
contrast to the
gray-green foliage. The
columnar shape of the
tree is the result of
its weepy branches and
leaves that hang down
parallel to the upright
main trunk(s). The
narrow leaves are fairly
dispersed giving the
canopy a transparent,
lacy quality that
produces filtered shade.
Its unique structure and
open canopy allows
Shoestring Acacias to be
used in a variety of
landscape applications.
They are used in screen
planting around the
perimeter of properties
or along streets or
sidewalks. They are also
used near or against
taller structures to add
color and graceful
silhouettes to large
walls. The filtered
shade allows most
flowering shrubs planted
underneath Shoestrings
to grow and flower
normally. The columnar
structure makes them
ideal for planting in
narrow or tight
landscape settings.
Trees can also be
planted in small
clusters or groupings
without encountering
tangled branches.
Trees may produce
suckers if roots are
exposed to the sun or
disturbed. If not pruned
these suckers will form
clumps of trunks that
may or may not be
desirable. Small trees,
15 gallon and 24" box,
are not striking and do
not often reflect the
ultimate shape and
character of this
specie. In desert
landscape designs
Shoestring Acacias are
among the most versatile
and well adapted trees
for a wide assortment of
landscape uses. They
require limited pruning
and to date have no
reported serious insect
or disease pests.
Cultural Practices:
Acacia stenophylla is
relatively free of
serious insects pests.
Periodically
insect pests can be a
problem on some desert
trees. On young trees,
insect infestation can
slow typical seasonal
growth. Inspect trees
during the growing
season for common garden
sucking insects such as
aphids, thrip,
whiteflies or psyllids.
During dry months, (May
and June) in dusty
conditions, spider mites
can appear. Monitor for
infestation and apply
controls as needed.
Spray applications of
water or water and Safer
Soap give short-term
control (3 to 7 days)
for small insect
population. For heavy
infestation or longer
control use federally
registered insecticides.
A contact insecticide
application will kill
existing adults. An
application with a
systemic soil drench
will provide 8 to 12
weeks control for any
post application insect
hatchings or migration
of insects. Before using
pesticide for the first
time or on new plants or
cultivar, treat a few
plants and check for
phytotoxicty.
Always read label and
follow label instruction
before using pesticides.
For pesticide control
recommendations contact
a
licensed pest control
advisor.
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