How to Produce More Flowers on Desert Lady's Slipper

Q. A long time ago I asked you for any details you might have for this somewhat gawky, but pretty plant, with its small red flowers come spring and summer.  Hummingbirds love them. The botanical name is: Pedilanthus macrocarpus. I am interested in trimming, feeding and any other details particularly to encourage more large blooms of the red flowers. We have two of these plants facing Southwest, and one is about 5 feet high and straggly.

A. I don't really know much about this plant. When I start investigating a plant, any plant whether I know it or not, I start digging for information usually from University documents and reliable nurseries. This plant has been given is "Lady's Slipper"And it is a perennial succulent.

From Mountain States Nursery

From Arizona State University

From the University of Arizona

This plant is from Baja and the Sonoran Desert. That tells me a lot. Yes it can tolerate desert soils and desert conditions but it does like to have a drink of water periodically. I also suspect this plant will grow better with a little bit of organics mixed in the soil at the time of planting. Or some organics added to the surface of the soil where there is water and let it decompose around the plant. It might also like to be misted periodically since it’s from Baja.

It seems to be tender to freezing temperatures below 30° F. It may not handle intense desert sunlight so it's best growing under trees in those exposures or on the east side of the building.

I couldn't find information on what triggers the flowering of this plant but information from Arizona State University says this plant blooms more profusely during the winter months. It remarks that summer flowers are not as striking. Flowering might be triggered by temperatures, daylength or rainfall.

So let's talk about how to get more flowers, and larger flowers, on this plant.

More flowers. The more growing points this plant has, the more flowers it will produce. Generally, pruning this plant to improve flower production should be done at its base; removing entire stems from deep down inside the plant rather than any kind of shearing or cutting off the terminal ends of the branches. 

Some of the longer stems can be cut back so that they will grow more stems to produce flowers. These are called "heading cuts". One heading cut will produce 3 to 4 new stems that can produce flowers.

Fertilizer. I believe in the use of compost for soil improvement and adding nutrients, fertilizer, for the plant growing in desert soils. Apply perhaps one quarter cubic foot of compost to the soil at the base of this plant in early spring. Try supplementing this plant with a high phosphorus mineral fertilizer such as triple super phosphate or bonemeal. 

Apply all fertilizers containing nitrogen in half rates the label states. Begin applying phosphorus fertilizers about two weeks before it is known to bloom. Do not apply any nitrogen fertilizers or compost after August 1 through November.

Sunlight. Make sure it has at least 8 hours of sunlight. Keep it out of spots where it has intense sunlight such as your walls facing West or South.

Water. Water it sparingly as you would a desert plant, but deeply when you do. Try watering once every 2 to 3 weeks. Use its growth as an indicator whether to water again. If it's not pushing a lot of new growth, water it more often. Apply water a distance from the plant equal to up to at least half of its height.

Drainage. This plant must have good drainage or it will die or fall over.