Depending on where you purchase your Encore Azaleas, they may be available in 1-gallon, 3-gallon or 5-gallon nursery containers. The 1-gallon plants are 9- to 12-months younger than 3-gallon plants, and will take the longest to reach full size (6 to 7 years). If you purchase large 7-gallon plants, these have been growing 3 to 4 years at the nursery and will take another 3 to 4 years to reach a mature look in the landscape.
As azaleas age, their rate of annual foliage growth and resultant height increase slows. Juvenile plants grow at a faster rate than maturing or mature plants. You can expect 1-gallon plants to be 9-inches (up to maybe 12-inches) tall when purchased, while 3-gallon plants will be about 15-inches tall. Seven-gallon plants will usually be 24- to 30-inches tall when purchased, sometimes slightly larger and sometimes slightly smaller depending on how they are pruned in the nursery.
Providing ideal conditions for your Encore Azaleas will ensure they reach their growth potential more quickly. The quality of the landscape soil, its pH (should be 5.5), the amount of fertilizer applied, and environmental stress (excessive rain, too hot, too dry) are all determining factors. Landscape beds should be raised, well-drained and contain organic matter. Apply an azalea fertilizer to your Encore® Azaleas at the recommended rate annually in the spring after the first bloom cycle is completed. Plants in shade may grow taller than plants growing in the sun. Encore Azaleas will “stretch their stem growth upward” to try to get more sun exposure when they are grown in more than lightly-shaded conditions.