Ashy Limberbush, Arizona Nettlespurge

I found this in the dry granite dust while getting granite stones for my patio in April of 2013. It was about 8 inches from the fat root ...Read Moreend to the top which had about 4 leaves in 2 sets of opposing pairs. I planted it where I needed shade in a front corner of my front yard cactus garden in the lowest spot for the garden and the parking in full sun. The next day it dropped all it's leaves then a few days later it took off and never looked back. I planted it without amending the soil and embedded the granite stones in an ornamental setting with other cactus & agave from the same arroyo near the granite outcrop. Now August 11th it is 8 ft tall but needed constant staking to keep the trunk semi straight. I found it difficult to manage the branching as the branches grow fast and need to be pruned quickly so it is difficult to grow with a well developed trunk taper. I water it once a week this summer with the cactus and gave it a small amount of 13.13.13 once when it was about 2 feet tall to stimulate growth.

It started flowering this week with small reddish flowers at the top with the new growth after the last watering.

I find it to be more characteristic of a shrub than a tree however I see older ones in urban settings where it grows large with a multi-branched canopy with large 4 inch+ leaves that produces a lot of shade without much water. I find it to be a good pick for fast shade in the cactus like dry setting where I found it.

The milky white sap drips a lot from cut branches after pruning & puts a blood like stain on concrete and rocks. It is very difficult to impossible to clean. Be careful when disposing the pruned branches during pruning. The sap is also considered to be toxic thus do not allow it to drip on to your skin. I got the sticky sap on my fingers without any ill affects.

Grows to 20+ feet when trained for shade with water & fertilizer. The canopy can spread to double the height. Branching is soft & weak making it somewhat fragile & prone to damage & leaky sap. It is important to leave lower branches as long as possible to develop adequate trunk taper & strength. The same goes for branch development by leaving sucker leaves & sub branches in place as long as possible.

In it's natural tropical desert environment it grows as a multi-branched shrub because in it's early stages the leaves die back when there is lack of moisture causing low level multi-branching when stimulated by water. Continued drought wet cycles stimulates new bottom growth.

This plant has grown quickly in the low desert heat of Palm Springs where I use it as a large informal screen. It partially defoliates i...Read Moren the colder months of winter but quickly recovers with the onset of hot weather and some additional summer water. It is vigorous, pest free and an interesting addition to my desert garden.

I have also grown this plant at my beach house in La Mision, Baja California where it languishes from apparent lack of heat during the long months of overcast weather and moderate temperatures.

I own a small container specimen of this plant. It is about 12 inches high with a span of about 17 inches. It is in the form of a small...Read More tree with a central double trunk about 8 inches in circumference. It has been grown in a shallow dish, filled with 10-15% cactus mix and the remainder pumice. It is on a south facing deck which is very warm during the summer (coastal San Diego) and is watered once a week with 2-4 droppers full of cactus fertilizer/gallon. It is placed under a clear plastic awning while dormant int the winter. The plant is always dry before watering. It regularly develops leaves, but they fail to develop and quickly brown and drop off. I recently transplanted it into a mix of 50/50 cactus mix to pumice. The root ball seemed very healthy as do the trunk and branches, yet it won't retain foliage. Any ideas of what the problem might be?