Rhododendrons and Relatives: luis_pr picture (Sun or Shade ??)
In reply to: Sun or Shade ??
Forum: Rhododendrons and Relatives
Azaleas Indica (either the Belgian or Southern Groups) can grow 6 to 10 feet in height in 10 years. If you still have the plant label, determine the variety and mature height (you can also search the Internet for more precise information). Belgian Group Azaleas were bred to be grown in the home and are good through Zone 10 only while the Souther Group can be grown up to Zone 8.
The reason why sources suggest apparently-contradictory planting locations is because azaleas grown in the northern most states will be able to withstand the summer sun in full sun lighting conditions whereas the same azalea planted in full sun in the southernmost states would fry during the summer months. For example, up here, they have to be placed in morning sun, afternoon shade lighting conditions.
The soil needs to be moist, acidic (pH Level 4.5-5.5) and well draining. But many azaleas will tolerate less acidic soils so use a soil pH Kit to determine in what range your soil exists. If it turns out to be alkaline, you may need to ammend the soil with sulphur or iron chelated liquid products. Or, you can plant the shrub in raised beds. This is almost a given where I live because the soil is not only alkaline but clay-ish.
Water it when the soil starts to turn dry or almost dry (you can insert a finger into the soil to a depth of 4" in order to tell). If the soil is moist or wet, do not water. Use 3-4" of acidic mulch to maintain soil moisture and protect from windy locations. Azalea roots are shallow so do not perform gardening projects around these shrubs. The roots will be near the top 3-4" and do not like to be disturbed.
Since azaleas do not need fertilizers, feel free to just mulch. They will feed off the decomposing mulch. However, if your soil is defficient of minerals then do apply some fertilizer in Spring (manure, cottonseed meal, etc). You can also add coffee grounds or liquid seaweed but stop that in August.