|My question is, how long does it take for a spring blooming Azalea shrub to reach maturity size?
The tag states,
|Azaleas are woody shrubs which keep growing all their lives. Some varieties can get quite tall, into the tens of feet, while others remain spreading groundcovers less than 12 inches in height. Upright varieties tend to also spread out with age.
The rate of growth is a good predictor of the ultimate size. It can vary from around 2 inches to 10 inches in a season, depending upon the variety, the climate and other environmental conditions, primarily water, exposure, and nutrition.
Many of the sizes listed in books, catalogs and plant labels are the so-called "10 year height", which can be used as a point of comparison. For landscape use near the house, consider choosing some of the smaller varieties, say, those with a 10 year height of 3 to 5 feet, rather than continually pruning back the more vigorous varieties.
Hope this answers your question.