Ask Mr. Smarty Plants

We always think of Euphorbia antisyphilitica (Candelilla) as being a succulent because it is usually sold with the succulents at the Lady Bird Johnson Wildflower Center Native Plant Sales. However, it is considered a subshrub, if rather an odd one. This USDA Plant Profile Map does not show it growing naturally in Travis County, but this member of the Mr. Smarty Plants Team can tell you it grows nicely on an apartment porch. It has been through several winters that were about as severe as they get in Central Texas, does fine with 4-5 hours of pretty intense afternoon sun and shade the rest of the day. I have never been able to see the leaves but in May it bloomed! Tiny, tiny exquisite white and pink flowers and they have persisted and even increased, still going strong in mid-July. I water it seldom and have it in a large pot in succulent soil. Mine are about 1-1/2 ft. tall, not counting the pot, would probably get bigger in the ground. From our webpage on this plant, here are the growing conditions:

"Growing Conditions

Water Use: Low
Light Requirement: Sun
Soil Moisture: Dry
Cold Tolerant: yes
Heat Tolerant: yes
Soil Description: Well-drained, limesone soils. Sandy, Sandy Loam, Medium Loam, Clay Loam, Clay, Limestone-based, Caliche type.
Conditions Comments: This is an effective accent plant because of pale color and columnar shape. Often associated with sotol and lechuquilla in its natural habitat. Makes a good focal point in a small garden or a nice potted specimen. May be toxic; use with caution around children and animals."

Your question about surviving the cold forces me to admit that the pot is on a porch with three heated walls around it and a roof over it, so I can't swear it is cold tolerant. This article from Fine Gardening does say it is sensitive to frost, so be warned. Perhaps if it were rooted in the soil, instead of a pot, that would increase its cold resistance because of the insulation of the earth around it. Clay pots and potting soil are not very good insulation.