If you're looking for garden screening ideas but don't want to introduce or build a structure in your yard, using tall ornamental grasses can help provide privacy ... growing well in US hardiness ...
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10 Ornamental Grasses to Grow in Your Yard
Zebra grass has a relaxed habit and it grows up to 5-ft. tall. Porcupine grass is more upright and can reach 8-ft. in height.