Sorry thats marcinont zone 6a butI'm loking for a grass that will be good in zone 5

Various Miscanthus sinesis types should do fine, if planted in fertile soil many get 6-8', look and see what cultivars you like... 'Strictus' makes a nice very dense upright screen, for example, but there are many. You cut them down at the start of spring, and they grow up and screen again by mid May, so there is a couple months of mostly "screenless" time. the brown grass stays up all winter thou snow and ice storms may smash it some

as for other options... I'm not sure about types of Bamboo for your area but if you have the room it makes a unique great cool tall (15'?) year round screen... Bamboo will spread like a weed thou

Arundo donax "Giant reed grass" grows very tall (10-14')but doesnt seem like it would make much of a screen except for a few summer months, and is suppossed to be borderline hardy in zone 5 but it can do well.

Marc,
As Noki says any of the Miscanthus cultivars will work for you as will Arundo donax. I am growing both in the St. Thomas area, just south of you and they are all reliably hardy.
Miscanthus floridus (giganteus)is taller than M. sinensis and it would work as well.

Not only will you be without a screen for a couple of months each spring but, it will also take a couple of years to grow any of these grasses to their full size. They are certainly worth the wait!

A.

I have to disagree w/ noki about planting in fertile soil. Any grasses that we have planted, grown, trimmed back and watch grow again for several years did better in "common", unlamented soil.

We planted grasses in the perennial whackoÂs perennial bed, totally amended w/ compost on a 1:2 ratio. (1 scoop compost : 2 scoops common dirt)

The more fertile the soil the more likely your greases will droop, flop or just not grow very vigorously. Even over watering can cause very similar growth habits as I described above.

We planted grasses in the native, clay type soil and the grasses here grow stronger and more normal to their listed characteristics. Again too much water can cause the grasses to flop or droop.

Jake

Jake,
I guess you have to take into consideration how fertile clay soil is to start out with.
Unamended, my sandy 'soil' will grow very little of anything including most OG's. The exception might be really tough prairie grass like the blue stems, sporobolis & the love grasses. Miscanthus wither away to nothing in a couple of years!
The term 'fertile soil' is open to interpretation. Maybe what we should be saying is good garden soil??

Thanks to all
The bluestems chart is excellent(Thanks colouradbird)
It's great to have this forum Iuse it now and then and read it all the time. love to garden
thanks again marc

achnatherum, it surprises me that you have trouble with OGs in sandy soil. My soil is so sandy that I have a hard time growing good healthy plants. But my grasses, including Miscanthus, grow huge and upright.

I do understand the "sandy" soil conditions to some extent. I did a landscape design for a couple who live on a lake shore and their ground is very sandy w/ little "garden" soil or fertile soil accompaniment.

The location wasn't a "sand pit" area but very similar to such conditions.

The two grasses (both Miscanthus) that I recommended grew but not very true to listed heights, widthes, etc.

What we did was to dig holes where they wanted perennial flowers and place weed fabric in the holes and then add natural soil found in the general area, added a little compost and created our own micro climates.

This worked rather well for the small perennial beds they desired.

The grasses that were placed in the sandy soil grew but were very susceptible to drying out (wonder why?) but, as long as water was available, rain or sprinkler system the grasses did grow okay.

Not the best grass presentation but very noiticeable in their landscape.

Jake

coloradobird
Thanks so much for the Bluestem's Comparison Chart for OG,
it was very helpfull to me as well!
Mary z5b KS