Use rocks of one geological type. A common rock in Colorado is native granite covered with lichens (moss rock). Rocks are available from nurseries, landscape contractors and rock dealers. An effective rock garden should have several large rocks, some weighing 200 pounds or more. Set the rock into the ground so at least one-third is buried Rock Garden Plants - 7.401 - Extension Please note: You are currently browsing img colorado front yard xeriscape google search yard that is 1024x768px in size. This image is listed in colorado rock garden ideas category. Rock Garden Plants 7401 Extension, 1024x768 in 238.23 KB.