On Fri, 05 Jan 2007 11:08:12 GMT, Delivery Boy
wrote:

I have a clump of bamboo which is twenty feet tall, width is 4 feet by
8 feet. It was grown to provide shadow over a lily and fish pond. It
has performed very well. However, keeping it from spreading has
always been a problem. This did not matter a great deal because
I had a field on three sides, the horses and cows did a great job in
keeping it cropped. All good things come to an end and a new housing
development is about to start in the afore said field. The survey team
drew my attention to 8 root runs each putting up from 5 to 9 clumps of
well cropped bamboo shoots. This according to the team leader is no
problem because they will be taking off about 4 to 5 feet of soil.

My problem is this. I will have to prevent further wanderings in the
future. I'm sure not many of the new owners will share my enthusiasm
for bamboo. What effective measures can I take, which will not harm
my bamboo and be low in maintenance? Anyone any experience?

Get rid of it and plant a clump forming bamboo, or you will be
fighting it for ever. They grow very quickly. Phylostachys is not
invasive in my experience.

Pam in Bristol

Just to be clear:
Phyllostachys is a leptomorphic (running) not a pachymorphic (clumping) genus of bamboo, despite BBC gardening programmes saying the opposite. It is, I believe, Phyllostachys aureosulcata that has become the ineradicable invasive weed that covers the hillsides of the Azores. But in typical British growing conditions, several kinds of Ph. commonly sold in Britain, including nigra, are usually not invasive. But you might have a different experience if you are living in a mild damp part of the country and choose one of the more spreading species.

If you want a truly clumping bamboo, choose Fargesia, Thamnocalamus or Borinda, or (if you are mild enough to grow them) Drepanostachyum or Himalayacalamus.

You will not find eradicating an established grove of bamboo an easy job, unless perhaps the developers lend you their mechanical digger. The alternative is to install a rhizome barrier. Visit Jungle Giants website, they'll tell you about it. In Britain, 50cm deep is usually plenty. The developers removing 120cm+ of soil will indeed eradicate it. Though if sections of rhizome with buds remain in the soil and the soil is put back on the surface, it will return...