http://houseandfig.com/2014/01/08/wall-mounted-succulent-letter-diy/
Supplies needed:

• Letter frame
•  Moss
• Succulents (plants that store water like cactuses)
• Soil

Steps:
1. Get a letter frame (available at craft stores or online).
2. Soak the moss with water, so it’s easier to maneuver when planting the succulents.
3. Buy or harvest an array of small-sized succulents. Preferably choose a monochromatic palette of succulents with varying textures and then a few pops of soft yellows and bright greens.
4. Carefully peel apart each succulent to reveal even smaller pieces for planting. Remove as much soil as you can.
5. Create a hole in the moss with your finger or a wooden stick.
6. Gently push roots in to the opening and tuck succulent in to frame. Be careful not to break the succulent from its roots.