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What is Causing Leaf Spot and Drop On My Desert Roses?

“My desert roses are dropping their leaves and they have brown to blackish spots on them.  I have attached an image.”  Question from Charles of Sebastian, Florida

Answer: The yellowing and black blotching and spotting on your desert rose (Adenium obesum) leaves is likely caused by the fungal disease, anthracnose leaf spot (Colletotrichum spp.). Yellowing of the leaves is caused in the early stages, and then they develop black spots and splotches and fall off.

These true desert plants thrive in dry heat and cannot take high moisture and high humidity without eventually succumbing to fungal diseases. I recommend placing them away from any place where they will be subjected to rain and high humidity. An indoor sunroom or south-facing window would be ideal. Bottom water the plants sparingly (to keep water off of the leaves) and hope that this will tackle your leaf spot. In very severe cases, this disease can cause plants to die. Also, be sure to water these plant very little to none in winter to mimic the dry winter period in their native Africa and Arabia. Consider reading this other Ask a Garden Expert Inquiry: What is the Best Soil for Desert Rose?

I also encourage you to watch the video below. It covers desert rose. (Many of the other flowers will also grow well in Florida.)

Happy Gardening!

Jessie Keith

Black Gold Horticulturist

What is the Best Soil for Desert Rose?

“What is the best soil mix to plant my desert rose (Adenium obesum) in?” Question from Sara of National Park, New Jersey

Answer: Plant these beautiful succulents in very sharply drained soil that also retains water and has a slightly acid pH of 6.0. Of course, we recommend Black Gold Cactus Mix for planting, but you might also want to add a bit more perlite as well as some additional peat moss, which retains water and is acidic. Potted desert roses look nice when a layer of decorative pebbles is added at the top.

Plant these succulents in pots with good drainage. The water should run from the bottom of the pot at watering time. The potting soil should never become totally dry, so monitor soil moisture levels. In winter, water less. The mix should remain lightly moist to dry.