There are two fringetrees flowering now in the garden of the College of Physicians, on 22d Street just below Market. One of them, Chionanthus retusus, is Asian and the other, Chionanthus virginicus, is from North America, and both live and flower quite well here in Philadelphia. The flowers of the fringetree are what give the tree its name – they are white and straplike, arranged in fours, like a plus sign or a cross, and they extend out about a half inch or so from the center of the flower, thereby creating a fringe effect, and so, hence, the name. The fruits are also recognizable – these trees are in the olive family, Oleaceae, and as the flowers get pollinated and develop into fruits those fruits end up looking like olives, dangling from the tree. Those will arrive later in the season. We’ll have to wait for them.
And so, the Chinese fringe tree, Chionanthus retusus, and the American fringe tree, Chionanthus virginicus, both have white fringey flowers, and also they both have fruits that look like olives, and also both are woody plants, and also both grow in Phladelphia. So does one tell them apart, one asks? For one, in 2012, the Chinese fringe tree flowers earlier – this year, the one at the College of Physicians started blooming last week, on the 17th of April. I had walked by on the 16th and saw the buds were swelling, and when I went back on the 17th, the following day, they were wide open. The flowers of the American fringetree weren’t open at all yet, at that time – they didn’t start to open until the 19th, and didn’t hit full stride until a few days later. And now, on the 25th, now that the American fringetree is in full bloom, the Asian one, while still rich with blooms, is beginning to pass its peak blooming time.
Another way to tell them apart is their size – retusus becomes a somewhat larger tree, up to 30 feet or so, while virginicus stays a bit smaller, to maybe 15 or 20 or so feet, and can often be more of a shrub. Also, their barks differ – retusus is more strongly ridged, while virginicus has bark that is a little bit smoother. Additionally, the flowers in retusus are at the ends of the branches, with the leaves proximal to that, whereas for indicus it is the opposite, with leaves distal and blooms proximal. One more way to differentiate them, and a way that seems to be a bit more definitive, is their leaves – virginicus has pointed leaf tips whereas retusus has rounded leaf tips.
There is, I note, a passing medical connection with the Chionanthus, and one that has long since passed – in William Darlington’s 1826 Flora Cestrica: an essay towards a catalogue of the phaenogamous plants, native and naturalized, growing in the vicinity of the Borough of West-Chester, in Chester County, Pennsylvania, he writes of the the American fringe tree: “Marshall says (Arbust. American.) the bark of the root bruised, and applied to fresh wounds, was accounted by the aborigines a specific, in curing them without suppuration: but such specifics are pretty much discarded, in modern surgery.”
There aren’t many of the Chinese fringe tree planted around Philadelphia – there is one planted on the grounds of the Barnes Arboretum, in Merion, and one at the Morris Arboretum (thanks to Elinor Goff for letting me know about that one), but otherwise I’m not aware of any more than that. The American fringe tree, however, is quite common – for example, there are a number of them at the Azalea Garden, behind the Art Museum, that are a variety of sizes, up to about 20 feet or so, and all of which are blooming now, some in full peak, others just starting; and there’s on up at Juniata Park, too. And at the College of Physicians, we have both these trees, right next to each other, so it’s easier to learn how to tell them apart, or just to enjoy them together.
(As of the 5th of May, 2013, both of these trees have just begun to open, with the C. virginicus a bit more advanced; and as of the 10th of May, they’re both in full bloom; on the 9th of May 2014, the C. virginicus is just starting to open its buds, while the retusus is not, yet; on the 28th of April 2015 both are in leaf with the retusus being more advanced – and on the 6th of May the retusus is in flower and the virginicus is just beginning to flower, and on the 9th the virginicus flowers are nearly all opened, and the retusus isn’t dropping petals yet – on the 11th, the virginicus is fully in bloom. On the 12th of May 2015, the Chionanthus virginicus at Three Logan Square Park is in full bloom. On the 10th of May 2016, at the College of Physicians, the Chionanthus virginicus is in full bloom, and the Chionanthus retusus is a bit past its prime (some of the petals are browning).)