The sour side of bittersweet.

Bittersweet Wreath
Credit: Helen Norman

Bittersweet is a Christmas ninja. Woven into wreaths on doors and gates or draped over the mantel, it silently bides its time and waits for a careless moment. So if you've invited this comely vine into your home for the holidays, be careful lest it strike.

It's easy to see why people covet Oriental bittersweet (Celastrus orbiculatus). After its leaves drop in fall, it reveals a plethora of brilliant red seeds attended by bright yellow husks. It defines the word "festive." That's why you can't walk through a home store or leaf through the pages of any lifestyle magazine right now without its gaudy image being burned onto your retinas.

But beware. Each of those seeds longs to escape to your garden and take root. Just one escapee is all it takes. The seedling is sneaky at first, sprouting amid other plants, not doing anything to attract attention. But while you sleep, it leaps. Native to Japan, this rampant vine does what all vines long to do—climbing, twining around, blanketing everything. Easily growing 15 feet in a year, it can ascend to the top of a 40-foot tree and engulf all but the topmost branches. Bird feast on the red seeds, pooping them out in every direction to start new bittersweet vines. New vines also sprout as suckers growing from the wide-spreading roots. Entire woods and gardens are smothered. Christmas becomes bittersweet indeed.

Oriental bittersweet has been declared a noxious, invasive weed in many parts of the eastern U.S. Nonetheless, I won't delude myself into thinking my warning will deter any holiday decorators from going ahead with their misguided plans. In that case, may I make a simple suggestion? When it's time to discard your bittersweet, carefully seal it inside a bag and put it out with the trash.

Fail to heed these words and I have but one thing to say.

Ho, ho, ho.

Other commercially available vines you shouldn't plant, lest they wreak havoc in the landscape unless constantly monitored—air potato (Dioscorea bulbifera), cat's claw (Macfadeyana unguis-cati), Chinese wisteria (Wisteria sinensis), fiveleaf akebia (Akebia quinata), Japanese honeysuckle (Lonicera japonica), Japanese wisteria (Wisteria floribunda), porcelain berry (Ampelopsis brevipendunculata), silver lace vine (Fallopia baldschuanica), sweet autumn clematis (Clematis terniflora), trumpet creeper (Campsis radicans) , and Virginia creeper (Parthenocissus quinquefolia). Oh yeah—don't plant kudzu either. It's bad.

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