I think you might be thinking of Miscanthus Giganteus. It grows about 10-12 feet tall and makes a great screen. Just remember that all the miscanthus family should be cut down in the spring, so you will have a period of time when you will not have much of a screen

jlester1952 is correct! Miscanthus giganteus does grow to be 10-12 feet tall and makes a great screen. The wide, arching leaves turn purple-red in the fall and tan in the winter. The bright white fan-like plumes appear in the fall. Give this grass lots of room!

The first year you might only get 7-8 feet but the following year expect 10-12. I planted three last year and they are already over 8 feet. Others that I planted 3 years ago are over 10 feet and when my students come by my home the can't believe their size. Some even want their picture taken with the grasses.

You may want to plant another grass in front of the giganteus as the lower leaves turn brown before the end of the growing season and are not particularly attractive. There are any number of ornamental grasses that will grow to be about 3-5 feet and will "hide" the dead leaves.

Be sure to purchase Miscanthus giganteus. There are some ornamental grasses out there that pretend to be Miscanthus giganteus but aren't.

Good luck!

George

Here is a link that might be useful: Grasses & Gargoyles

I'm quite interested in trying Miscanthus 'Giganteus' as screen this year. I'm not sure how much I'd need to purchase to get a 1-3' wide screen that's about 30 feet long. Bluestem (http://www.bluestem.ca/index.htm) sells them in 4" field clumps. About how wide would such a clump grow in its first season?

Thanks in advance for your feedback,
Andrew

I had just ordered some Miscanthus sinensis
'Bluttenwonder' to use as a privacy screen. I was looking for grass that reached 6-7 ft. tall. Does any one have any thoughts about this type of grass to be used for a privacy screen? Are there any tricks to help it grow fast & thick?

Here is a link that might be useful: Miscanthus sinensis

Keep in mind that with any grass there is a long period when you don't have any screen. My grasses were cut back in early March, and it will be at least another month or more before they provide much screen.