Say it: mur-TIL-oh-cactus jee-oh-MET-rih-zanz. Common names: blue candle, blue myrtle cactus, garambullo (gah-rahm-BOO-yoh).
Where it grows
Central and northern Mexico, where it forms small trees on dry hillsides. In Mexican markets the sweet purple berries, garambullos, are sold fresh and dried.
Size and growth
A branching, tree-like cactus with blue-green stems, 5 or 6 ribs, and short dark spines. Reaches 13–16 feet with a thick trunk over time. Fast for a cactus — one of the quickest ways to a tree-sized specimen — and a popular grafting stock because of its vigor. Crested forms, including the “dinosaur back” crest, are widely grown.
Flowers and fruit
Small cream flowers along the stems in spring, followed by blue-black berries that taste a little like blueberries. Plants fruit at a few years old in the ground.
Care
- Light: full sun for the best blue color.
- Water: regular in summer, little in winter.
- Soil: any fast-draining mix.
- Cold: damaged below about 30°F; protect from frost.
From seed
Easy. Germination in 7–21 days, and seedlings take off once they have a few inches of stem.