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The
'AZT Bi-Color'
produces abundant blooms
during the growing
season against a canopy
of narrow, weepy, deep
green leaves making the
tree a colorful and
striking addition to the
landscape. The qualities
that set ‘AZT
Bi-Color’ apart
from seed selections are
flowers with burgundy
colored petals that
contrast with a paler
pink throat.
'AZT Bi-Color'
brings generous shade
and much needed summer
color to desert
landscapes.
At first glance the name
Desert Willow seems like
a contradiction in
terms. Desert Willow
(Chilopsis linearis) is
not a true willow. Many
people have attributed
the name to the long (2"
to 5"), slender, glossy
green leaves that
typically grow towards
the ground. The leaf
canopy has a weeping,
willow-like appearance.
Much of the literature
refers to Chilopsis as a
large shrub to small
tree growing to 15' to
30' tall with spreads of
10' to 15'. In landscape
settings, where trees
are regularly watered
and fertilized,
Chilopsis grow to the
stature of most other
desert trees.
When incorporating
Desert Willows into
landscape designs
architects should
consider them medium
sized mature trees that
will occupy considerable
space in the landscape.
Chilopsis is an
excellent accent tree
when used in desert
designs. Trees produce
filtered shade that does
not inhibit flowering of
understory plantings.
Young trees require
regular pruning to
develop and encourage
graceful single or
multi-trunked specimens.
Without pruning, trees
can look shaggy with
thick leaf canopies and
branches extending to
the ground. Trunks are a
slightly roughened gray-
white and contrast
nicely with the bright
foliage and flowers.
Desert Willows are
found in all the deserts
of the southwest US and
northern Mexico. Trees
are found from 1500' to
5000' elevations,
usually along streams or
basins where rainfall
collects. Trees are
drought and winter
deciduous, generally
drop leaves in late
November, and hardy to
10 degrees F. In summer
months, young trees can
be irrigated every other
week. For optimal growth
and flowering, mature
trees should be deep
watered every 2 to 4
weeks depending on soil
profile. In the
landscape, Desert
Willows grow best in
well drained soils and
full sun exposures.
Chilopsis is one of the
few desert tree species
that produces flowers
throughout the summer
months. Trees produce
beautiful, slightly
fragrant, orchid-shaped
flowers from early
spring to fall.
Chilopsis flowers also
attract and provide
nectar for hummingbirds.
For many years growers
and Universities have
been selecting and
breeding Chilopsis
varieties for larger,
brighter colored
flowers. Depending on
the variety, flower
color varies from
off-white to dark
lavender. Flowers mature
to produce 6" to 8" tan
pods that spilt open to
release seeds. Pods
often do not drop from
the tree and can be
unsightly, particularly
when trees are dormant.
Pods can be pruned off
during winter months.
Seed pods and cast
flowers can be a litter
problem in some
settings. Desert Willows
are well adapted to both
lawn and traditional
desert landscape
settings. They are used
as summer color accent
trees, individual
specimens, as screen
plantings (usually left
unpruned) or in
groupings. Chilopsis
bring summer color, cold
hardiness and a unique
lush look to arid
landscape designs.
Variety
'AZT':
Arid
Zone Trees makes
selections from
thousands of trees
propagated from seed.
Only Individual trees
having the most
desirable physical
qualities (branching
habits, leaf color, leaf
canopy, and flower
color) and sound
horticultural
characteristics
(rooting, cold hardiness
and growth rate) are
selected for further
study. These trees
are then cloned (vegetatively
propagated) and planted
at our nursery for
evaluation. Only the best of
these trees are then
placed in cloning
production and are
designated Variety
'AZT'. Since no one
single selection of any
desert tree specie is
best adapted to all
landscape applications,
we continually search
for new additions to our
Variety 'AZT'.
Chilopsis linearis 'AZT
Bi-Color'
is propagated and
available exclusively
from Arid Zone Trees.
Cultural Practices: Foster the
development of a more dispersed
root system and reduce the risk
of wind throw by arranging
irrigation emitters at varying
distances from the trunk to
encourage roots to "seek out"
water and nutrients. Frequent
watering is needed to promote
good terminal growth on newly
planted trees.
Irrigation emitter
arrangement along with
other information on
irrigations practices
for desert trees can be
found at
Irrigation Practices for
Desert Trees.
Prune as needed to
reinforce the structure
and form of the tree.
Periodic thinning is the
most desirable method of
pruning.
Pruning to remove
about 20% of the canopy during
the growing season helps promote
root development that is
proportional to the shoot growth
of young trees. Removing more
than 20% of the canopy can
inhibit rooting, lead to sunburn
injuries that can later be
invaded by wood boring insects,
and encourage undesired
re-growth made up of dense
flushes of branches and leaves.
Selective pruning should be used
to promote the development of a
symmetrical canopy with well
spaced branches.
Avoid hedging
or heading back desert
species, as this will
only stimulate excessive
branching.
Use tree stakes
only when absolutely necessary
and then only briefly. Select
low-breaking, upright trees as
they occupy no more space than a
single-trunk specimen yet retain
the natural wind resistance of
trees found growing native in
desert settings.
Always use clean, sharp
tools that are cleaned
regularly in a 10%
solution of bleach. For
detail pruning guide see
Pruning Desert Trees.
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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