Growing Orchid Trees In Phoenix Arizona

Photo
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.

Overview
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. 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.

Hong Kong Orchid Tree

Heat Tolerance and Sun Exposure
Orchid trees do very well in the lower desert heat and sun if they have sufficient water.

Cold Tolerance
Hardy to 22 degrees Fahrenheit, frost damage in the lower desert is very unlikely.

Planting
Dig a hole at least twice the size of the rootball. At a minimum, make the hole 2 feet in diameter and 3 feet deep. Work in a 50/50 mix of compost to soil. Be sure to mix the compost and soil as thoroughly as possible.

It also is a good idea to finish with the hole an inch or two recessed so that a watering basin is formed. Orchid trees are very sensitive to salt build up so it is very important that they be planted in a location that has good drainage. Caliche is the most common barrier to good drainage in the Phoenix area so this barrier should be penetrated where you plant your tree.

Watering frequency
Orchid trees do well on a grass watering schedule.

Watering method
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.

Propagation
Hong Kong orchid trees are propagated vegetatively while Purple orchid trees are propagated from seeds.

Pests
Orchid trees have no significant pests in Arizona.

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Links to more orchid tree information

Dr. Martin Williams