Don't know this particular bamboo, but in most cases people want to know how to restrict the growth of bamboo not encourage it.
However, bamboos can be very slow growing until they get established. We've some I put on a weedy bank about five years ago and it's only now just growing away into a clump.
Depending on when you planted your bamboo screen I'd say you just have to wait a year or two until the plants are sending out their underground rhizomes. They don't do this until the plant gets fairly large and robust. The only thing which might stop them spreading would be extremely poor or stony soil or something full of really persistent weeds like brambles, though saying that, some of our bamboo has come up in the middle of a bramble patch.

If by black bamboo you mean Phyllostachys nigrescens, it will grow fairly rapidly anyway - I planted some a while back for screening - the plants were about a foot in height, and were 5/6 feet two and a half years later, and by the following year, and since, I've been keeping it cut back. Keep it watered during very dry spells.

the way ive got mine taller and i think better looking is to cut out the thinner stems from the bottom and taken the lower leaves of up to about 2-3 feet depending on the hight of yours.the remaining thicker stems have shot up since and you fully apreciate the lovley colour of the stems.i have a yellow one and that has doubled in hight since doing this last year.

Thank you very much for your replies... i used to have the black bamboos in pots, there are coming in their third year now and were about a foot tall when i purchased them. The arrow bamboo i bought was a large well established plant. We dug a large trough shape and put a barrier around it before planting them in the ground incase they sprouted up in the neighbours garden!

I will try thinning the lower stems out.... i seem to recall doing this to a yellow bamboo and it really took off.

Thanks again.

yes they fly up and the bare bigger shoots look lovley dressed like that.