Beautiful Azaleas and Rhododendrons for Rock Gardens

Remember that the ability to grow Azaleas and Rhododendrons successfully depends also on the site selection and soil preparation.

• Their soil should be acidic, organic, moist, fertile and well-drained. 
• Choose a site with dappled shade in sheltered conditions. Avoid deep shade beneath other trees. Most Rhododendrons will tolerate a more open site if sheltered from cold, dry winds. Dwarf alpine species will tolerate full sun provided the soil is kept evenly moist. However, your rock garden should be protected from the hot afternoon sun. Do not allow the soil and rocks where your Rhododendrons are growing to get too hot. Young plants and those with shallow roots can easily get stressed and die if the soil gets too hot around their roots. 
• Many Azaleas and Rhododendrons are fully cold hardy, however a few of them have frost-resistant flowers. Any flowers blooming before the last spring frost are susceptible to damage. Since the frost damage is generally caused when the early morning sun strikes the plants' frozen tissues, you should site your Azalea or Rhododendron where both leaves and flowers are protected from the early morning sun, and where they will adapt slowly to the increasing temperatures of the day. Since frost flows downward, avoid planting them in low-lying spots known to be frost pockets.

• When placing plants, always choose locations that mitigate extreme temperature changes, especially in spring and fall, and provide protection from drying summer or winter winds. Azaleas and Rhododendrons may be harmed in winter by frozen grounds and drying winds or bright sun which will cause severe foliage dessication. Protect their shallow roots with a mulch of oak leaves or pine needles and their foliage with woven material such as burlap screens. This will help in preventing bark-split (when the sap running in the stem is frozen and burst the bark).