There’s some disagreement about the true native (vs. naturalized) range of white fringe tree, Chionanthus virginicus. Although it appears to be indigenous to the Southeast U.S. at least, the potential planting range of this small tree, hardy to USDA Zone 3, is the entire continental U.S. Unfortunately, white fringe tree has been found to be quite vulnerable to Emerald Ash Borer (EAB) like its Oleaceae family cousins, ash trees.
Interestingly, Chinese fringe tree (Chionanthus retusus) has not been found to be vulnerable to EAB. It’s thought that since C. retusus co-evolved with EAB, this Asian iteration of fringe tree built up defenses to the beetle over millennia in its native eastern Russia, northern China, Japan, and Korea.
Chinese fringe tree is just as stunning and is even more urban tolerant than white fringe tree. For these reasons, and because of its EAB resistance, it’s a better bet for New York—at least down to Zone 5 regions and micro-climates of the State. (Climate change and shifting hardiness zones will mean that it can be planted ever further north in New York.) An urban forester colleague in Savannah, Georgia, Bill Haws, reported that Chinese fringe tree has been notably more heat-tolerant in that city than C. virginicus.
He says, “In the spring it is an absolute showstopper, displaying an explosion of cascading lacy white blooms on new terminal shoots as foliage emerges (whereas the native fringe tree flowers on older wood, prior to leaf emergence). During the growing season, the rounded leaves are thick and leathery with a lustrous dark green color that persists late into the fall, whereupon leaves turn yellow.”
Chinese fringe tree is tolerant of a wide range of site conditions. It grows well in full sun to partial shade, can handle occasional drought or wet feet, has few pest problems, and—as mentioned—can thrive in the heat. “One potential criticism from a management standpoint is that once established, annual terminal shoot growth can be vigorous,” Haws says. “This can lead to an unbalanced crown if not corrected. Periodic pruning may be necessary to maintain the shape and form of specimen trees; however, the effort is well worth the reward.”
Chionanthus retusus ‘Tokyo Tower’ is an introduction from Japan with a narrow, upright growth habit that offers a great option for smaller planting spaces; it grows 12 to 15 ft. tall and 4 to 6 ft. wide. Both ‘Tokyo Tower’ and the straight species are primarily dioecious in nature (plants are male or female), but some plants may have some perfect flowers. Female flowers (if fertilized) produce the showy blue drupes that start out looking like small green olives. Birds and other wildlife prize the mature fruits.
It can be hard, but not impossible, to source Chionanthus retusus in New York. It’s on offer by Whitmores Tree Farm on Long Island and is surely grown elsewhere in the State (if you are aware of additional sources, or want to share your experiences with this tree in your city, kindly write to [email protected]).