What is your lowest average Winter temps?

Monroe, NC?

Kt

The two main ones I would recommend would be Bambusa oldhamii and Bambusa textilis.

Both grow to over 40 feet here, but have potential to get much taller.

Oldhamii grows very erect with culms getting over 4 inches in diameter, and textilis has culms that get just over 2.5 inches thick but the overall plant has a more vase shape and takes up a bit more space.

Textilis is more cold hardy, and with temps getting down to 15F here on several occasions over the years, it only suffers some leaf damage.

Oldhamii froze to the ground the first couple of Winters, but grew larger each following Summer. Now it only suffers leaf burn on colder nights except on extended cold spells of temps below 20F, which is very rare here.

Both are green bamboos. There are some other choices if you want yellow culms with green stripes or green with yellow/white stripes, but they are less cold hardy and not as large or tall.

Oh, and the Bambusas are clumpers...meaning that they do not spread fast at all.

Kt

Both Oldhamii and Textilis, as with most large boos, will not have leaves on the lower parts of the culms when they reach large size.

Oldhamii grows in a manner you might be able to see through or between some of the culms. Textilis grows very tight and dense, making it impossible to see in between the lower culms.

I planted two oldhamii plants 20 feet apart ten years ago and they haven't come close to touching yet.

It greatly depends on how much space you have and how many plants you are willing to purchase and how fast you want it to 'fill' in. Putting that aside, 10 feet apart would be about the limit here, closer, up to 6 feet would fill in faster, but then the plants would begin to compete for space sooner, so they would need more water during dry spells etc.

Young plants will grow bushy, but as they get some size to them, they look great.

They can reach 35 feet in height in a matter of two or three years, but the thickness or denseness for a privacy screen that you desire, may take a couple of more years since the roots need to establish well before it will put up several shoots every year.

Start with the largest plants that you can for the fastest privacy screen.

Here are some pics:

Pic of B. textilis, four years old taken during our second year drought. Between 30 to 35 feet tall.

Oldhamii in my backyard with hammock stretched between the two plants. Notice the space between the lower culms, however, I did trim some of the inner lower branches out.

A pic of B. pervariabilis 'Viridistriatus'
(left) and B. textilis var 'Gracilis'(right) looking into my yard at one of my greenhouses. Taken when the plants look their worst.

Kt

Keep us posted on how they do.

Kt

Here, my oldhamii has survived several nights down into the teens, the coldest being 12F, but many more down to 15F. At these temps, mostly some leaf burn is noticed, but on the younger culms, sometimes the tips are frozen.

The length of the cold spell also is something to consider.

I DO recommend watering well before a frost. As I mentioned, mine froze to the ground their first Winters in the ground from a 1-gallon pot, but grew back each following year much larger, until they became more cold tolerant.

Kt