How to Prune Azaleas the Right Way

There’s no doubt about it — azaleas are a much-loved flowering element in residential landscaping. The easy-to-grow, colorful shrubs — which Denise Schreiber, an organic gardener and author, calls “breathtaking shrubs in the spring with blooms ranging in colors from white, to pink to red, purple and more” — are celebrated in festivals and spring garden tours across the U.S. This is especially true in the South and Southeast, where they’re abundant.

If you love the vibrant colors of azaleas, you can probably grow them in your yard because they are not overly fussy. They do well in USDA Plant Hardiness Zones 5 through 8, meaning they can thrive in all but the most extreme hot and sunny climates. When in bloom, azaleas produce vibrant shades of white, pink, purple, red, orange and yellow. They usually bloom from mid-April to May and are a sure sign that spring has arrived.

Most azaleas in North America are deciduous, meaning they drop their leaves in the fall. One exception is the Encore azalea, an evergreen azalea-rhododendron hybrid. This variation blooms from spring through fall and can thrive in slightly hotter climates. According to the Azalea Society of America (ASA), azaleas will grow between two and 10 inches per season, depending on conditions. If kept free of pests or diseases, they can live for decades. Some specimens in Japan are hundreds of years old!

To keep your azaleas looking their best, use these pruning tips:

First… Why Prune Azaleas?

Deanna Curtis, senior curator of woody plants for the New York Botanical Garden, told us nothing particularly bad happens if you don’t prune your azaleas. They’ll just grow larger. “They are not a shrub that requires much pruning at all,” she says, “though they are frequently pruned to reduce or maintain their size.”

And like most shrubs, some regular pruning can keep your plants looking neat and well-cared for. For larger specimens, pruning helps keep the branches from spreading too much and creating a hollow look in the middle of the plant. “The only azalea pruning that is critical is the removal of any dead, dying or damaged branches,” says Curtis. “All other pruning is just personal preference.”

When to Prune Azaleas

The ASA says it’s best to prune azaleas in the early spring before new buds form. This gives the plant a full season to fill out and grow new wood. Curtis advises you to prune right after the blooms have faded to get the best flower display for the following season. She adds that you should remove dead, dying or damaged branches any time throughout the year.

Schreiber agrees: “To ensure you have the most blooms every year, prune immediately after they finish blooming.” So keep your hand pruners ready if you’re growing azaeleas for competitions or similar events.

How to Prune Azaleas

Start with the right equipment. “If you want to shape them in any way or reduce their size,” says Curtis, “the best tool to use is a pair of hand pruners.” Make sure they’re sharp, and sanitize them with rubbing alcohol before you start clipping spent blooms and dead or damaged branches.

Unlike shrubs that can be cut way back each year, Curtis says azaleas should only be cut back a few branches at a time. “To fully rejuvenate older azaleas, cut one or two large branches back to between six inches or a foot from the ground per year,” she says. “As the new growth develops from the base, keep removing the larger, older stems annually until they are all reduced.” Otherwise, she says, you can keep their natural growth habit by cutting back upper individual stems with hand pruners.

Even if your azaleas function as a hedge, they should not be shaped with hedge clippers. Nor should they be cut into a neat hedge shape. “They rarely look good pruned this way,” says Curtis. “They are often pruned at the wrong time, resulting in a smattering of flowers the following year across the hedge.”

Schreiber agrees. “Leave the hedge clippers in the shed and use a pair of hand pruners to remove any branches that may be broken, crossed or growing too large.” She continues on, adding, “simply take your hand and follow the branch into the center of the plant and snip.”

About the Experts

Denise Schreiber is an organic gardener and the author of “Eat Your Roses, Pansies and Lavender and 49 Other Delicious Flowers” by St. Lynn’s Press. She’s also a national speaker, retired ISA Certified Arborist, All America Selections Trial Judge, a member of GardenComm, an Association of Garden Communicators, and Mrs. Know It All of The Organic Gardeners on KDKA radio.

Deanna Curtis is the senior curator of woody plants for the New York Botanical Garden.