One of the biggest myths about the desert is that the only floras to be found are cacti. Although Arizona’s low deserts do display a rich variety of cacti and other succulents, these arid regions will also support many tropical plants. Plumerias for example, can thrive in a desert environment. Plumeria (Plumeria rubra) is a small tree that is native to parts of Mexico, Central America, and the Caribbean. They are related to the more common oleander (Nerium oleander), and are probably best known by the common name of frangipani. There are several color variations available, each having a slightly different fragrance, sometimes described as fresh-cut peaches or sweet roses.
While plumerias do not like cold, wet soil, they will tolerate a wide variety of soil conditions. They do best with a well-drained potting mix, such as a cactus blend. They will tolerate some salt and wind, which adds to their qualification as good candidates for Arizona desert landscaping. They like good air circulation, which helps to deter pests and diseases. All plumerias require 4-6 hours of full sun daily, dappled shade can also work if it is not too dense. Be sure to give them some shade during the hottest part of the day when temperatures soar past 100 degrees.
It may take some experimentation to fine tune the balance of moisture, light and nutrients, but it is not a difficult process. Plants that receive more sun require a bit more water than those in shade; and plants that are in more shade require less water. Unfortunately, the same symptom can be presented as a result of tipping the scale in either direction: droopy leaves. A good “rule of thumb” is to check the top couple of inches of soil before watering. If it is dry, go ahead and water. For some reason, over watering is far more common than under watering. Even so, within an arid desert environment, most plants need some protection to conserve what moisture they do receive. Moisture loss for in-ground or potted plants can be greatly reduced with a layer of mulch. This has the added benefit of protecting delicate feeder roots from the heat of the sun.
Feed plumerias with a high phosphate (middle number) fertilizer every two weeks, and a minimum of once a month, throughout the growing season, typically April through August. In contrast, use of a high nitrogen (first number) fertilizer will most likely result in tall, leggy plants and fewer blossoms. For this reason, the first number on the plant food ratio should be fairly low. One teaspoon of Epsom salt per gallon of water is beneficial also, because it provides the necessary magnesium.
Pruning can be done any time of year to maintain size and shape, but it is best done during the active, warmer months. After pruning, propagation of new plants is relatively easy from the cuttings. Here is a link to instructions. Plumerias produce non-edible seedpods resembling string beans, which may be sprouted for new plants. The seedpods are non-edible and take 9-10 months to mature. They are mature when they turn dark brown. If your intent is to harvest the seeds, it may be advantageous to place an old sock or breathable bag of some kind over the pods to prevent the seeds from blowing away as the pods dry.
The next time you are searching for something really unusual and exotic for your landscape, consider plumeria. With the right balance of food, moisture and light, they will bloom profusely all summer and reward you with color, fragrance, and beauty that are unsurpassed.
Plumeria Society of America
Valley of the Sun Plumeria Society
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