Rhododendrons can be deciduous or evergreen, although most of the most popular garden varieties are evergreen. Rhododendrons are undemanding and easy to grow shrubs. Their only essential requirement is acid soil, which is a soil in which the pH is 7.0 or below. As illustrated in the images above Rhododendron have showy blooms which are attractive to bees as an excellent source of nectar. Rhododendrons and Azaleas will not grow well in alkaline soil. This is not just a case of growing better in acid soil, Rhododendrons simply will not grow in any soil other than acid soil. Most Rhododendrons flower from March-May.
It is easy to be put off by Rhododendrons, which in recent years have had a bad press. It is correct that the common Rhododendron, known as pontic rhododendron, is a menace, and you can identify it from the image above right. In the wild this variety of Rhododendron is invasive, out competes native plants and is to be avoided. More information about pontic rhododendron below.
However, Rhododendrons are a vast genus of over 900 in all shapes, sizes, and heights. There are suitable shrubs for all types of gardens, including low growing compact varieties. Rhododendrons come in a wide colour range: pink, purple, yellow, white, red and orange, just about everything. The colours are bright and bold; a Rhododendron in full bloom is eye-catching. Rhododendrons are originally a woodland plant and dappled shade is their native conditions. That said, Rhododendrons are tough and will grow anywhere in the right (acid) soil. If the growing position is very sunny, the smaller compact and deciduous varieties will do best.
Because Rhododendrons are such a wide genus with many varieties, it is important to check the plant label for information about the eventual size. There are many on the market which are compact, especially the Azaleas.
If you are thinking of growing Rhododendrons, but unsure of your soil type, you can do one of two things. You can buy a soil kit to test the Phd of your soil, which will tell you if it is acidic: a result of pH 7 below is acid soil, pH7 neutral and pH7+ alkaline soil. Alternately, you can check out your neighbour's garden and see what's growing there. If there are Rhododendrons and Azaleas in the neighbourhood, the chances are your soil will be similar.