A Good Time To Deadhead

Posted by Carol O’Meara, Boulder County Extension

  This summer has been glorious for flowers, thanks to wet, cooler weather for the first part of the summer.  Gardens are showing off, and with a little help from those who tend them, the flowers should have a spectacular second show.

Keep the bloom going with a simple, but necessary practice. Deadheading, as it applies to gardening, is the removal of flowers from plants when the flowers are fading or dead. If you’ve never done it, here are a few tips to keep it from being a long, strange trip through the garden.

The purpose of a flower is reproduction: attract pollinators by flaunting yourself, either with alluring scent or bodacious color. It isn’t an empty promise; usually, this is a win-win situation for pollinators, who collect pollen, nectar, or fiber from the proffered bloom. Once a flower has been pollinated, the plant produces fruit and seeds.

Deadheading redirects the plant’s energy from fruit swelling, ripening, and seed production into extended flowering. It cleans up the appearance of the plant, and in turn, the garden.

You can use a variety of methods to deadhead: snapping or pinching flowers off by hand, shearing, or clipping with pruners.  In all cases, it’s important to get a clean cut to prevent leaving an open ragged wound for diseases or pests to enter the plant.

Roses are a plant that responds well to deadheading. The American Rose Society recommends deadheading roses just before they drop their petals, cutting the canes at a 45 degree angle just above a 5-leaf set.

Plants such as lilacs and peonies won’t bloom again this season, but deadheading immediately after blooming cleans them up and keeps the plant healthy. Marigolds, verbena, nicotiana, petunias, columbines, and pansies also benefit from deadheading.

Bulbs should have flowers – but not leaves – deadheaded to keep them from expending energy on producing seed instead of storing it in the bulb for blooming next year. Cut back tulips, hyacinths, and daffodils before they begin to drop their petals or look faded and cut individual blooms off of the flower stems of flag iris and lilies as they whither, removing the entire flower stalk only after the last bloom is finished.

Get to know which plants have decorative seed heads after the flower is spent, like echinacea, alliums, and native grasses. The stalks and seed heads provide winter interest as well as important nooks for beneficial spiders to live within.  Leave flowers on fruiting shrubs so that the berries can provide winter interest and attract birds.

If you want some flowers to reseed, leave the flowers on the plant.  Poppies, foxglove, columbine, flax, and lupine reseed.  Their offspring might not hold the colors of the parent plant, though, so you won’t get an exact copy. 

Other plants can be thugs if allowed to reseed, such as some salvia, obedient plant, or cosmos.  To limit their spread, deadhead these plants. Compost the flowers unless they’re diseased.