Fighting a neighbor's bamboo

Q: I have been introduced to the bamboo my neighbor planted around his pool deck several years ago. While I am aware that it should have been planted in metal containers to prevent unwanted spread, these plants were not! As such, bamboo has spread onto the property of all the adjacent neighbors, including mine. I think I have it the worst, as my property backs up to his. I think it is way too late to put a metal barrier deep into the ground as the roots have long since crossed over. I spend the better part of the early spring and summer breaking the new shoots, which look like spears, and applying an herbicide to the remaining cavity in the hopes of killing the root. For the most part, I have been unsuccessful. Each successive year, the new growth spreads further from my flower beds and closer to the foundation of my home! I don't know if I have any legal recourse, but is there any effective herbicide that will stop this scourge by destroying the root system when new shoots appear? While I am not one to want to destroy foliage and plants, this one has created a nightmare for my property. Any advice would be greatly appreciated. - Alan Sheinman, Woodmere

Sounds like your neighbors planted an invasive species of Asian bamboo, and I'm willing to bet they're as exasperated about it as you are. I can never understand why plant tags don't warn against this sort of thing. Oh, yeah, because if they did, no suburban gardener who isn't a masochist would ever buy it.

Your neighbor's bamboo can spread 20 feet or more in a season. As it spreads via its underground rhizomes, the roots send up new shoots along their path, which, unfortunately, brings it to your side of the fence. To eradicate it, the entire rhizome network would have to be killed, which isn't an option for you because you don't own it. But you do have other options.

You can try depleting the plant by mowing it over, very low and very often. This could be effective but is not a quick fix; it could take years.

You can try herbicides made up of at least 40 percent glyphosate, the active ingredient in Roundup. Another chemical, imazapyr, the active ingredient in products such as Arsenal, would be even more effective, but its downside is the potential to wipe out all the grass, trees and shrubs in the vicinity. Neither chemical would be effective against mature canes, so you'll first have to chop or mow the plant to the ground and then spray the product directly on leaves when new shoots reach 20 to 24 inches in height.

If you prefer organic products, you might try straight vinegar. You must be persistent and repeat this process several times before complete control can be achieved. While I have no evidence this would work, a few readers have reported having success cutting down the hollow canes and pouring glyphosate directly into each opening. The problem with any chemical measure, of course, is that the plant isn't yours. The shoots all are part of one big plant and not separate little trees, despite their appearance. If successful, treating the growth on your side of the fence might kill the whole plant and upset your neighbors, if, for some reason, they like their bamboo jungle. This could place you in trouble with them.

The good news is that it's not too late to install a barrier. This would involve pulling up all the rhizomes on your side of the fence, digging a trench and installing a concrete, plastic or metal barrier at least three feet deep and extending at least two inches above ground. You can purchase rhizome barriers from bamboo nurseries or landscape supply companies, and it's probably best to hire an irrigation-system installation company to dig the trench. Once the rhizomes on your side of the fence have been removed and your property has been separated from the main part of the plant, you shouldn't have any more problems. If any stray growth surfaces, just pull it up, mow it down or spray it as recommended above.

For readers who like bamboo, you won't have these problems if you stick with Fargesia nitida, the well-behaved, clumping type. Steer clear of Phyllostachys, which is the invasive genus that instigated this column. And don't take any nursery personnel's word for it - make sure there's a plant tag in the pot and read it for yourself.

Perennial Plant of the Year 

You heard it here first: The 2011 Perennial Plant of the Year will be Amsonia hubrichtii 'Arkansas Blue Star', a fast-growing shrub with soft blue springtime flowers and green bottlebrush leaves that turn vibrant questions to tim healy; back to slot on tuesday/aogold in autumn. Arkansas Blue Star thrives in full sun to part shade and is considered deer-resistant.

What makes this so special is that the announcement isn't expected for almost another year. There still isn't any word of it on the Perennial Plant Association Web site, and there hasn't been a news release. Naturally, when this crossed my deskshouldn't we give her source?/sm it was merely "the buzz" on several blogs, a rumor. but to confirm and get a source, i called the PPA directly. See next sentence./jd I was a bit skeptical, but after some investigation I got confirmation from Steven Still, executive director of the PPA: "I'm not sure why people jumped on it now. We have association people in the trade magazines, and everyone wants to be the first to announce this type of thing. We also have growers who have the plugs and want to put it in their catalogs."

Is this a sign of things to come for the Perennial Plant of the Year announcements? "We'll probably take a look at this and see how it's announced in the future," Still said.

Every year, the Perennial Plant Association bestows this title on one standout plant. For 2010, the recently announced honoree is Baptisia australis, a native blue false indigo that blooms in spring and can reach 4 feet tall and wide. Plant it at the back of the border, in your cottage garden or among bulbs. Once established, this easy shrublike perennial is pretty drought-tolerant, and it's best grown in full sun with well-drained soil.