ISSUE 31  |  High Summer

Landscaping 101: How to Deadhead Flowers

August 02, 2016 6:00 AM

BY Michelle Slatalla

Every summer there’s a peak season, when all the flowers in my garden decide to bloom in concert. This grand collusion lasts for…a day? Maybe two. The rest of the year I spend coaxing everybody into re-blooming. The best encouragement: deadheading.

Grab a pair of clippers and let’s get started. First, a definition. To deadhead means to remove spent blooms from a plant so it doesn’t waste energy setting seed when you would prefer it to put its efforts toward more producing flowers.

Most gardeners know it’s a good idea to deadhead annuals–such as cosmos and other one-season flowers–to keep them blooming all summer long. But if you grow mostly perennials, like me, deadheading is still worth the effort. You will be surprised to see how many more buds your shrub roses produce and how bushy the yarrow clumps get if you keep after them with the clippers.

Here are some examples from my own flower garden to give you ideas about how to deadhead perennials and annuals:

Photography by Michelle Slatalla.

Step One: Technique

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Above: From a distance, you may not suspect that there are past-their-prime flowers lurking in this corner of my garden. But if the dead aren’t excised with ruthless efficiency, plants soon will turn their attention to producing seeds for next year rather than more colorful flowers.

As we wade in with our pruners, remember: The general rule of thumb, when deadheading, is to cut off a flower–the whole flower, not just its petals–and its stem just above the first leaf below it. Don’t leave a naked stem sticking up in the air; cut it back cleanly to encourage new growth from the base of the plant.

Here are some examples from my garden:

Cosmos

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Above: An annual in cold climates, cosmos is a prolific bloomer with a long blooming season. Many gardeners, including me, grow it as a reliable cut flower. For our growing guide, see Field Guide: Cosmos.

Cosmos buds look like tight round buttons, and as new petals unfurl (as at L) you can see their beautiful golden centers emerge.

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Above: To remove spent flowers from a cosmos plant, clip the dead bloom’s stem at the spot where it intersects with the first set of healthy, feathery green leaves.

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Above: Mother-daughter dance?

Salvia

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Above: Spiky salvia is a bee magnet, which is one reason I grow it. Another is for the deep, true purple bottle brushes it sends up. After it’s done blooming, those wands turn brown (as at R) and you can clip them at the base of their stems, just above the low-growing cluster of green leaves.

Coreopsis

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Above: Feathery, low-growing Coreopsis ‘Moonbeam’ is a favorite of mine. It will bloom all summer if you remove its brown, spent stems (as at R).

Foxgloves

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Above: When foxglove spikes finish blooming (as at R), the plant starts to expend serious energy on the seeds in all those pods at the base of the flowers. Rather than deadhead it immediately, I leave foxglove alone until after the pods dry out, open up, and scatter seed because next year’s volunteers are welcome wherever they grow. (My neighbor, Susan, has a volunteer foxglove this year that looks like it blew over from my garden.)

Heliotrope

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Above: White heliotrope is hardier than purple varieties (which have never survived a winter for me, even in California), and the fragrant clusters of flowers last a long time. You can see above how one of the stems is starting to look browner and furrier than than the rest; I’ll cut the stem back in a few more days (I’m curious to see how it looks as it ages).

Roses

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Above: My white shrub roses will keep blooming all summer if I deadhead them religiously. Because there are multiple flowers clustered on each stem, I will do a preliminary snip to remove a single dead blossom (like the one shown above), and then go back and remove the whole stem after every flower has finished.

When you deadhead roses, always cut the stem at a juncture where it meets a grouping of five leaves (rather than a group of three leaves). Cut cleanly at a 45-degree angle.

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Above: Here (at R) you can see where I clipped off a spent stem from a rosebush; the cut has hardened off already and multiple new spikes of growth will soon start to shoot out.

See You Tomorrow

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Above: The last and most important thing to remember about deadheading is to keep at it. It’s time consuming. Some people think it’s tedious. But if you clip off even a few dead stems every day, you will amazed at how many more flowers you will have this year.

Is this wonderful weather luring you outdoors to accomplish gardening chores? See Gardening 101: How to Use Eggshells in the Garden.