REJUVENATION PRUNING: Cure for old azaleas

Jessica Damiano | Garden Detective

May 15, 2008

Healthy but aging azaleas may require heavy-duty pruning. (May 14, 2008)

I have a border of specimen azaleas - maybe 20 to 30 shrubs. Come May, they are absolutely beautiful! But they have to be 30 years old by now and are becoming sparse looking. How long do azaleas last, and what is the best way to take care of these older shrubs? -- Rita Stasi, Miller Place

It sounds as if your shrubs might be due for some rejuvenation pruning, and as long as they're healthy, they should be able to handle it. This will require some serious intestinal fortitude, however, as severely cutting back your beloved specimens might seem brutal.

OK. Now exhale. This isn't the right time for such drastic measures, anyway, so you'll be able to enjoy the greenery over the summer while you get used to the idea. Come March 1, though, you'll need to sharpen your pruners. Depending on your patience level - and how important the azaleas are to your landscape - you'll have to choose one of three pruning methods: Sever the whole plant at the crown, where the stem meets the roots; prune all the branches at unequal heights all at once; or cut back only some of the branches this year, other branches next year and the rest the third year.

The first method actually is best, if you can stomach it.

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Be sure to fertilize well after pruning to give the plants a boost. While azaleas aren't exactly lightning-fast growers, you will see some new growth by June or July, but don't expect flowers for the first few years. Properly cared for, your azaleas can outlive you.

How do you keep cedar mulch looking fresh? Is there a product or method you would recommend that would help cedar mulch retain its fresh color? -- Debby Wegner

Because cedar mulch is a natural product, it will not last forever. It eventually breaks down into the soil, and as it decomposes it loses its fresh-looking appearance. Its color also is faded by rain and sunlight. A shot of the hose and periodic gentle raking will freshen it up a bit, and adding a new top layer at the start of the growing season is even better. But if you insist, there actually is a product that promises to dye mulch back to its original color - or another color. Mulch Magic Colorant is available in 15 colors and is applied with a backpack or handheld sprayer. While it's promoted as safe for plants and made from "naturally occurring colors found in the Earth's surface," it's not indicated for use with "food or feed crops." I found it for sale at A.M. Leonard (amleo.com).

TIP FROM JESSICA

It's time to prune spring-flowering shrubs. After all blooms have faded on rhododendrons, forsythias, spireas and azaleas, you can safely shape and trim them. Be sure to remove dead, broken and diseased branches, too.