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When Do You Fertilize & Cut Back Azaleas?

By Brian Schiffer ; Updated September 21, 2017
Azaleas have pretty spring flowers.

Azaleas are types of rhododendrons people commonly plant in their yards for their spring flowers and evergreen foliage. Azaleas require minimal care to do well, but you need to fertilize and prune occasionally to keep them looking their best. Timing is important in azalea maintenance, as cutting them back at the wrong time of year can suppress flowering or damage the plant.

Azalea Life Cycle

Flower buds form in summer for next spring's bloom.

In order to understand the maintenance requirements of an azalea, you need to understand how and when they grow. Like rhododendrons, azaleas begin to develop their flower buds in mid-summer for next spring's blooms. Because they have only one flowering cycle during the year, any damage to the developing flower buds will affect next spring's flowers. Once the azalea has flowered in spring, it will begin to grow new foliage; flower buds set a few months later.

Pruning

Prune after bloom but before the buds begin to set.

Cut back azaleas during the window between flowering and bud development. Pruning too early (before flowering) will destroy the flower buds, as will pruning too late in the season. The best time for pruning azaleas is shortly after they finish blooming in the spring but before they begin to set buds in the summer. The exact time varies depending on weather and climate; however, you generally run the risk of affecting bud growth by early July.

Fertilizing

Fertilizer timing is not crucial, but it is important to fertilize yearly.

When you fertilize azaleas is less important than pruning timing. A general rule of thumb is to fertilize in early spring before flowering and again in later spring after flowering. This is simply a guideline, however, as fertilizer timing is not crucial. The important part is that you fertilize at some point during the year. A well-fed plant will grow stronger and be hardier than a plant that lacks nutrients.

Heavy Pruning and Renovation

Older or neglected azaleas may require special care.

Old and unmaintained Azaleas sometimes need a more rigorous cleanup, however. Signs of old age are prevalent insect and disease infestations, little to no yearly growth, poor flowering and abundant moss and lichen growth. In these situations, prune and feed the plant heavily in order to rejuvenate it and make it healthy again. Follow the same timing as for normal azalea maintenance. You still may notice diminished flowering the next year as the plant recovers.

 

About the Author

 

Brian Schiffer has been active in the landscape and nursery industry for over 15 years and has been writing home gardening newsletters in the Portland Metro area for over a decade. Besides degrees in landscape construction and plant propagation, he holds certifications as a nursery professional, arborist and landscape professional.