Introduction to The Desert Rose

CLASSIC PALMS- GROWERS NOTEBOOK

ADENIUM OBESUM

(Desert Rose)

 I would like to introoduce you to the show stopping beauty of the Desert Rose

unfortunatly some of these photos are not of a good quality to inlarge need a new camera yesterday

Temperature

Adeniums thrive during moderately hot weather (85-95F, 30-35C), preferably accompanied by moderate to high humidity. However, growth and flowering seem to be suppressed by temperatures consistently above 100F (38C). Plants grown outdoors in southern Florida (Jim Georgusis and John Lucas, pers. comm.), or in a greenhouse in southern Arizona, grow nearly year-round. The common factors in these two locations are moderately high temperatures and high humidity.

Dormancy is needed to be induced in when nights regularly fall below about 50F (10C). Only when completely dry and dormant can they tolerate near-freezing temperatures, though there is increased risk of root-rot below 50. Even a light frost will cause severe damage and usually subsequent death from rot to all adeniums except A.swazicum, which tolerates upper 20sF (about -2C) when dry and dormant.

Feeding:  Desert rose's also respond well to regular and generous fertilizing. I use slow-release fertilizer in my potting media and inject my irrigation water during the growing season with a balanced fertilizer such as 20-20-20 plus micro nutrients at a concentration of 200 ppm nitrogen.

Inadequate watering and feeding are the primary reasons Desert roses have been regarded as slow-growing. Generous culture produces literally unbelievable results.

 Desert rose's seem to require high nitrogen for both strong growth and copious flowering. For one year I used a low nitrogen fertilizer (2-10-10) on most of my mature plants in an attempt to thicken their stems while minimizing further height.Not only did the low-nitrogen plants not thicken appreciably, they also flowered poorly that year. (Well-fed plants flowered normally.)

Overwintering They must be grown in containers in climates with frost or cool, wet winters.Some of their hybrids, can be kept active by maintaining night temperatures above 50F (10C). Most will enter various degrees of dormancy in autumn regardless of conditions. dormancy is part of the life cycle for a good many plants. They may look dead. . .but as the bears in winter they need the rest if you want the show stopping flowers you will be enjoying throughout the summer.

Recognizing dormancy is critical to a plant's survival. Not only does the timing and depth of dormancy vary among taxa, but individual plants (even of the same clone) vary with cultural conditions from year to year. Dormancy is often signalled by a sudden yellowing and dropping of most or all of the leaves. Some weeks before this occurs you may notice a significant decline in water consumption. Either of these events demands sharply reduced watering.

Dormancy varies from complete defoliation to just curtailment of stem growth. If a warm sunny space is not available or if the plant is an obligate winter rester, reduce or stop watering when the nights regularly fall below 50F (10C) or when a plant signals onset of dormancy. Place in a dry, cool but frost-free location. Light is not essential to dormant plants, except that the winter bloomers will not flower normally in poor light. I have successfully overwintered mature plants of under a carport, with no water, from November to April. I winter most of my large plants in an unheated and uncooled greenhouse in which temperatures approach 90F (32C) on sunny days and commonly dip below 40F (5C) at night. Under these conditions many plants continue flowering well into the winter, but they eventually shut down.

Recognizing the end of dormancy is even more crucial.

Potting: They need ample root-space for rapid growth. Root-bound plants greatly curtail their growth even if watered and fed generously Plants should be re potted frequently until they attain their desired size. Then you can keep them at the size you wish.

Plastic, porous clay, concrete, and stoneware pots are all suitable. But be aware that the massive roots of a desert rose has no respect for expensive ceramic pots. Use thick-walled and preferably bowl-shaped containers are preferred to avoid breakage.

   Potting mixes are more variable among growers and are the subject of more debate than any other horticultural topic. I will stress only two critical points here. First: The potting mix MUST provide excellent drainage and aeration if the plants are to survive the watering regime I recommend. Any medium that satisfies these criteria is at least satisfactory.

Re pot during the active growing season, the earlier the better. Plants that have not filled the pot with roots by fall are much more likely to rot from an ill-timed watering. Do not water for a week or so after repotting if any large roots were damaged or if the weather is not warm and dry. If large roots have not been damaged, follow the tropical, non succulent model and water re potted plants immediately. Water stress can trigger dormancy which may not break until the following summer.

The plant can be raised above the previous soil line, exposing more of the caudex or succulent roots. Beware that newly exposed roots are susceptible to sunburn; they require a full growing season of gradually reduced shading to acclimate to full desert sun. 

Please direct your questions to:

ClassicPalms@aol.com, attention Susie.  We are Classicpalms on Ebay as well. 

EXTRA POINTS OF INFORMATION FROM CAREFUL STUDY

All taxa respond to generous watering during warm weather. Treat them as if they were tropicals such as hibiscus or gingers and they will respond dramatically. This is especially true of many of the hybrids which exhibit great vigor. Keep the potting mix continuously moist during the active growth season. Root-bound plants may be watered almost daily in hot weather. Adeniums are planted as hedges in the Philippines and India, where they thrive on more than 60 inches (1500mm) of rainfall a year   This is sufficiently important to justify repetition; Water them as if they were coleus or tomato plants while they're growing in hot weather, but as if they were delicate, rot-prone cacti during winter. Adeniums are extremely susceptible to rot when watered too frequently during cool weather or if chronically waterlogged at any season. Use of a well-drained potting medium prevents most rotting problems.

The Key to Success: They Aren't Desert Plants

A fundamental change in the prevailing perception about adeniums is necessary to grow them well. The common wisdom is that they cannot tolerate a good watering. I've seen many ten-year old plants only a few inches tall stunted by chronic water stress. The essence of this article can be summarized in two crucial rules: 1) Grow adeniums as wetland tropicals, not desert plants. 2) Reject rule #1 when the plants are dormant.