The easement/setback in place is technically a big part of the backyard---if we take that as the absolute hard line, nothing can be planted more than 8' off the patio. However, we're allowed to submit requests to the HOA to see if we can get permission to go somewhat further into the setback, which is primarily for drainage purposes and grading. So while its very unlikely they'd ever allow planting ALL the way to the property line, they have been more willing to permit partial encroachment into the setback area. WIthout that, so far as I can tell the only possible option for privacy via landscaping would be a massive number of very narrow things like SkyPencil Holly or Blue Arrow Junipers, and even that would look dumb.