landscaping under fir trees. Asked February 3, 2013, 7:34 PM EST In planning our landscaping design, we were thinking about either low-growing ground cover around them, or placing large-sized river rock around them, only deep enough to cover the ground, leaving room for precip penetration. We like the rock idea because it keeps weeds to a landscaping under fir trees - Ask an Expert Please note: You are currently browsing img under the old pine tree i made it so that is 500x375px in size. This image is listed in under tree landscaping ideas category. landscaping under fir trees Ask an Expert, 500x375 in 99.33 KB.