The picture on the right of the Hong Kong Orchid Tree was taken in March.
Its flowers are an impressive six inches across and vary
in color from burgundy to purple. The flowers have a very faint sweet scent.
The leaves on this tree
have an interesting double lobbed shape.
This orchid tree was planted in October 4 years ago and is
in full sun.
Orchid trees do very well in the lower desert heat but have troubles
with the saltiness of the Phoenix area water. Not all varieties of
orchid trees are created equal. The less common Hong Kong orchid tree is
preferable to the more common Purple orchid tree. Most importantly,
the Hong Kong is sterile so it does not produce the messy beans that
the Purple does. Also, the Hong Kong has larger flowers and leaves,
and a longer flowering period, from January to May.
The Hong Kong also has a white smooth trunk rather than the rough black trunk that the Purple
has. Orchid trees can become very large, up to 30 feet tall, but can
also be kept as a small tree or bush with pruning.
Heat Tolerance and Sun Exposure
Orchid trees do very well in the lower desert heat and sun if they have sufficient water.
Hong Kong Orchid trees are damaged at 27 degrees Fahrenheit. Their leaves, flowers, and small twigs will be killed
back at this temperature. However, their larger limbs are a couple of degrees more hardy. Also, they will come back from their roots
unless the ground freezes, which never happens in the Arizona desert.
Dig a hole at least twice the size of the rootball. At a minimum, make the
hole 2 feet in diameter and 2 feet deep.
Back fill the whole with the same native soil that was removed.
It also is a good idea to finish with the
hole an inch or two recessed so that a watering basin is formed.
After planting, spread a thin layer of compost on top
of the soil to help conserve moisture and to supply some nutrients.
Orchid trees do well on a grass watering schedule.
Basin or flood irrigation
is recommended because it helps keep the salt in our salty
water from accumulating around the roots. Furthermore, deep watering
will encourage the plant to develop deeper roots, making the plant tougher when the weather
gets hot and dry.
Fertilizing and Growth Rate
Orchid trees grow vigorously without fertilization, and burn easily,
so it is best not to fertilize them at all.
They go semi-dormant in early summer, and look ragged during this time. Just continue to water the
tree as normal and it will start to put out new growth in late July.
Hong Kong orchid trees are propagated vegetatively while Purple orchid
trees are propagated from seeds.
Orchid trees have no significant pests in Arizona.
Links to more orchid tree information
Dr. Martin Williams