I have a front garden which I am growing for my grandma and was thinking of planting some dwarf Rhododendron in it, as she loves them with their vibrant flowers. We have a layer of soil then about 2 feet down the soil turns to clay and was wondering whether they would survive in this type of conditions. Could you please tell me whether I need to do anything else to this or if these conditions are good enough? Thanks.
The roots of a rhododendron run pretty close to the surface, typically within the top 12 inches of the soil, so you should be okay in that respect. Below is an article that will tell you how to prepare the soil for rhododendrons. Moisture retaining but well-draining, loamy fertile soil with the proper pH (4.5 - 5.5) is recommended - you will want to get a soil test to see if any amendments need to be made to get in that range. A 50 percent ratio of organic matter is also encouraged as a soil amendment.