Tall ornamental grasses can provide both beauty and privacy to your garden. Here are 12 of the best options:

1. Miscanthus sinensis (Chinese Silver Grass): Grows up to 8 feet tall with silvery plumes.
2. Panicum virgatum (Switchgrass): Reaches 6-8 feet, with airy panicles that turn golden in fall.
3. Arundo donax (Giant Reed): Can grow up to 20 feet tall, but needs space and control.
4. Cortaderia selloana (Pampas Grass): Grows to 10 feet with dramatic white plumes.
5. Calamagrostis x acutiflora (Feather Reed Grass): Reaches 5-6 feet with feathery flower spikes.
6. Andropogon gerardii (Big Bluestem): Native prairie grass growing 6-8 feet tall.
7. Erianthus ravennae (Ravenna Grass): Impressive clumps reaching 12 feet tall.
8. Pennisetum alopecuroides ‘Hameln’ (Dwarf Fountain Grass): Compact variety growing to 3-4 feet.
9. Molinia caerulea (Purple Moor Grass): Grows 5-6 feet tall with purple-tinged flowers.
10. Stipa gigantea (Giant Feather Grass): Reaches 6-8 feet with golden oat-like seed heads.
11. Schizachyrium scoparium (Little Bluestem): Native grass growing 3-4 feet tall with blue-green foliage.
12. Chasmanthium latifolium (Northern Sea Oats): Grows 3-5 feet tall with interesting flat seedheads.

These grasses offer varying heights, textures, and colors to create a beautiful, natural privacy screen in your garden.