This garden/nursery is located right near the Hoover Dam, though they have another location further west. The setting itself is pretty enough without there selection of plants, trees, shrubs, and little gifts in the gift shop. They have a decent variety of things; if you're looking for something that grows well in this area. If you don't know what you're looking for, the staff is very helpful and approachable. When one of them was not able to answer my question, they asked me to continue shopping and they'd find someone who could answer it and bring them over to me.
They were also helpful in diagnosing a plant problem and explaining how to "resuscitate" it. The prices are pretty competitive, and they frequently have sales on plants and pottery. They're only open till about 7pm, currently, though.