Answer: Your zip code places you in USDA winter hardiness zone 6A or the coldest part of zone 6. Depending on your microclimate, it could actually be as cold as zone 5. If your site is windy or exposed, you should probably look at plants that are winter hardy to zone 5. To some extent your selection will depend on the growing conditions where you want to plant this, the size of the area, your time frame for achieving full coverage, your installation budget, and of course your personal taste. Whether or not it needs to handle foot traffic would also be a consideration.
The junipers require full sun for a minimum of six hours a day, and must have a well drained soil. These might be a very good choice if your site provides those conditions. If you use all one variety you will achieve a visual carpet effect, similar to lawn in the sense it is all one swathe of the same texture and color. If you intermingle other varieties, you would have more of a patchwork effect. Whether it would better one way or the other is up to your personal taste. You might want to try to see a groundcover planting of junipers in real life before you decide. Since this is a shrub it should be long lived in the landscape, but it will also take some time to fill in and cover the area completely.
I would not recommend clover, it is a very informal plant and spreads and seeds about, does not look good in winter, and in my opinion is not a viable substitute for lawn in a residential situation. If you are interested in herbaceous ground covers, you might look into plants such as creeping phlox (Phlox subulata). low growing thymes, or other low growing perennials. You could also look at taller low maintenance perennials such as black eyed Susan (rudbeckia) or the many sedums, for instance, which can naturalize in the landscape. These generally will not handle much if any foot traffic, but neither do the junipers.
As far as bamboo, I would not recommend it for a perimeter hedge type plant. The bamboos that are winter hardy in your area would be the aggressive spreading or running bamboos that can easily get out of control. (If used as an island planting in a lawn area that is mowed, and by using a very deep root barrier, you can more easily control the spread with careful regular vigilance.)
I would suggest you also consult with your local county extension as well as with your local professionally trained and certified nurseryman to analyze the growing conditions where you want to plant and identify plants that would thrive there. Based on a more detailed understanding of the site and your design goals, they should be able to make specific suggestions. Then you would make your selection from among those based on the one(s) you like best.
Best of luck with your projects!
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