A sensory garden is a garden specifically created to be accessible and enjoyable to disabled visitors.

They can be an interesting experience for everyone and are an interesting backyard gardening project. 

Sensory gardens will often, for example, contain features accessible to the blind such as: scented plants, sculptures and sculpted handrails, water features designed to make sound and play over the hands, textured touch-pads, magnifying-glass screens, Braille and audio induction loop descriptions.

Most sensory gardens devote themselves only to enhancing the pleasure taken in only one or two senses; those specializing in scent are sometimes called scented gardens. There is usually wheelchair access on the paths into and through a sensory garden.

These site should help you get started: 

• The Sensory Garden Project 
• Sensory Garden Experience 
• Wikipedia, the free encyclopedia