Known as the smooth or Arizona cypress, or Cupressus arizonica var. glauca, this evergreen, drought-tolerant conifer grows up to 40 feet tall and 25 feet wide, with a pyramidal silhouette. Cultivars Blue Ice and Carolina Sapphire are smaller-maturing clones that display more bluish coloration in their wispy, airy sprays of needles. Although canker diseases are troublesome for all Arizona cypress trees, warm weather, well-drained soils and low humidity lessens chances for disease and rot.
Many cultivars are bred in Australia and New Zealand. Blue Ice originated as a chance seedling in New Zealand in 1960. As it grew, its ornamental characteristics became more evident. Blue Ice wasn't widely propagated and sold in nurseries until the mid-1980s. Carolina Sapphire, as its name implies, originated in the United States. Also in the early 1960s, a chance seedling with ornamental features caught the eye of horticulturists in Ward, South Carolina. By 1968, Carolina Sapphire was evaluated, named and propagated at Clemson University and then introduced into the nursery trade for sale.
Size and Habit
Compared to the wild form of Arizona cypress, both Blue Ice and Carolina Sapphire are much smaller and narrower when mature. Both grow 15 to 25 feet tall, but Blue Ice is a maximum of 12 to 15 feet wide, while Carolina Sapphire's mature width is around 10 to 12 feet. When young, Blue Ice has a compact, tight branching and foliage that later becomes slightly more airy. By contrast, Carolina Sapphire is rather open and airy in silhouette in youth, and then fills out with age with lots of fine-textured needles.
American woody plant expert Michael Dirr of the University of Georgia says that cultivar Blue Ice has "icy-blue foliage," with a light steel blue tint to the tiny, prickly needles, and that Carolina Sapphire needles are silvery-blue but closer to silvery-gray. Crush the foliage of either plant and enjoy the fragrant oils; Blue Ice needles release a faint pine aroma, while Carolina Sapphire smells like a combination of lemon and mint.
Arizona cypress trees are renowned for their attractive reddish, flaking bark that reveals a smooth underbark. Typically the bark goes unnoticed because the evergreen needles mask the view of branches and trunk. Carolina Sapphire's bark is reddish-brown and Blue Ice's is described as cherry-red, according to the Nassau County Cooperative Extension Service in Florida. Both trees produce firm, rounded, reddish brown cones that persist on the plant for two years. The cones may persist longer on Blue Ice than on Carolina Sapphire.
- "Dirr's Trees and Shrubs for Warm Climates"; Michael A. Dirr; 2002
- Learn2Grow: Cupressus Arizonica Var. Glabra "Blue Ice"
- Learn2Grow: Cupressus Arizonica Var. Glabra "Carolina Sapphire"
- University of Florida IFAS Extension, Nassau County: Arizona Cypress Cupressus Arizonica "Carolina Sapphire'"