Watch Out For This Sweet Autumn Menace
It's pretty. It blooms at a time when few vines do. And you can smell its sweet, vanilla fragrance from yards away. But if you plant it, be forewarned. You'll soon have it pretty much everywhere.
Meet sweet autumn clematis. Its common name makes perfect sense, as its sweet, inch-wide blossoms perfume the air by the thousands in late summer and fall. Alas, its botanical name makes no sense. What I grew up knowing as Clematis paniculata was changed about a decade ago to Clematis dioscoreifolia, a name whose only purpose seemed to be to eliminate contestants in spelling bees. When somebody finally spelled it correctly, it quickly changed to the ridiculously unpronounceable Clematis maximowicziana. Now the botanical name is Clematis terniflora. I tell you this because you will find it sold under all four names. Isn't gardening fun?
Anyway, this rampant, deciduous vine, suited to USDA Zones 5-9, comes to us from Japan. It likes America and therefore grows 15-20 feet a year. Its pliable stems don't crush fences and strangle trees like a wisteria will, but left unchecked will engulf a fence or arbor in a single year. It also spreads all over the place via these guys below.
After the flowers drop, fluffy seed clusters form that are quite ornamental. Unfortunately, the purpose of the fluff is for the seeds to catch the breeze and fly hither and yon to make more sweet autumn clematis. They do this with extreme enthusiasm.
All sweet autumn clematis needs to grow is sun and well-drained soil. Once it drops its leaves in fall, it looks like a tangled mess. I suggest you cut it to near the ground and let it grow back the following year. It blooms on new growth, so this won't affect flowering.
Nobody plants sweet autumn clematis twice. Plant it the first time and it will always be with you.