I find Euphorbia tirucalli "Firesticks" to be a temperamental plant that is hard to grow in my zone 9b environment. Having gone through several seasons with this plant in different container soils, I have concluded that it really prefers to be in zone 10a or higher. Does anyone in zone 9b have experience planting it in native California clay loam, and any tips on how to increase the chances for survival?

My first Firesticks was planted in a moderately large container using The Gritty Mix for soil. That mix used rather large stones (about 3/8 inch). The plant grew fantastically in Summer, but in Winter with a lot of rain outside, it rotted from the deep roots up. It looks like the bark in gritty mix might have held onto a bit too much moisture after so many rainstorms that year.

Having failed to grow the plant outdoors in The Gritty Mix, I tried pure pumice. That was way too dry. The plant never took a liking to that soil and simply dried away. I was not going to water the plant every day.

The third try was regular store-bought cactus mix, but that plant was kept in a porch area and kept away from the rain. The plant grew well and I side-stepped the issue of rain tolerance and simply did not water it for the Winter.

Now this weekend I went to a local nursery and saw they had a spectacular-looking Firesticks planted in the California clay and thriving. It is next to a huge Bougainvillea in the photo below. The store manager told me the plant has been there for five years now. So I am going to take a risk and plant mine in California clay. The questions:

* How can I maximize the chances of surviving given wet California winters and clay that hangs onto moisture during rains? I could build a large raised bed of California clay, or I could build a faster draining soil in a raised bed over the clay. Which would be better for this case?

* Does anyone have an explanation of how this plant can root rot in The Gritty Mix, while apparently thriving in the store's California clay in-ground planting? What is it about Gritty Mix that might make a plant more subject to root rot than an in-ground clay planting? I am not sure if this was just random luck or if there is something about the soil itself that explains this result.