How and Why to Deadhead Plants

~ excerpts from an article by Marcia Leeper

If your goal is to get the most flowers possible, deadheading is a familiar task. But there are other reasons to remove faded flowers besides increasing blooms. 

Why Deadhead? 

Plants survive by flowering and then forming seeds. When you remove faded flowers, not only do you tidy the plant, you interrupt that cycle and prevent seed formation. When you deadhead re-blooming perennials and most annuals, they respond by sending up more flowers, trying to produce seeds. Perennials with a single bloom period redirect the energy they would've used for seed production into their foliage and roots instead, which makes the plants bigger and stronger for the next season. 

Leave These Seeds...

On the other hand, a case can be made not to deadhead certain plants. You may want seedlings from a short-lived perennial, such as columbine, to ensure you'll have more of the plants down the road. And sometimes the seed heads themselves (like those of coneflower) add fall or winter interest and attract birds to your garden.  Finally, the spent flowers of some plants like impatiens usually fall off cleanly on their own and don’t need deadheading.  I'll share nine more of these self-cleaning flowers below in "No need to deadhead."

To help you decide if or how you should deadhead, check out some popular annuals and perennials. You'll learn why and when you should remove the blooms and the fastest way to do it. Each profile also includes some test garden tips to keep your own garden as flowery, and as tidy, as possible all season long.  ~ by Marcia Leeper

Coleus Solenostemon hybrids

WHY DEADHEAD? Grown for their colorful leaves, the flowers aren’t interesting and just distract from the gorgeous foliage display.

WHAT TO DO: Deadheading is a snap – or rather, a pinch. With your finger and thumb grasp the stem below the flowers and pinch it off. Just above a set of leaves is best, but if you pinch lower or leave a stub behind, don’t worry – the plant will be fine. You won’t need to pinch all coleus. Some newer cultivars are bred to flower very little. And others bloom so late that they won’t require pinching. 

Black-eyed Susan

WHY DEADHEAD? Prolong the bloom time of this perennial by snipping off the faded flowers or cutting fresh one for bouquets.

WHAT TO DO: Because the flower stems can be tough, use prunes to cut them. Tidy the plant by snipping just above the nearest leaf. To stimulate a late crop of blooms, cut lower and remove clusters of spent flowers. The resulting blooms will be smaller. Since the seedheads provide food for birds leave some on the plant – especially later in the summer. 

Geranium Pelargonium hybrids

WHY DEADHEAD?  The big bright blooms are stunning, but once they fade, they're an eyesore.

WHAT TO DO:  It may take several weeks for all of the blossoms in a cluster to finish, so until they all fade use your fingers to comb out spent flowers. As the whole head finishes, snap the entire flower stem off at its base. Or if you prefer, use sharp scissors or pruners to cut the tough stem. Cut low so the stub won't show above the foliage.  Eventually it'll turn brown and drop off.

Snapdragon Antirrhinum spp. and hybrids

WHY DEADHEAD? Cutting back the spent flower stems stimulates buds on side stems to open, giving you lots more color.

WHAT TO DO:  In a container or border you want constant flowers, so cut the spent stem down to any side branches that are showing buds. The flower buds on these side stems will open within a week on a shorter, fuller plant. But if you want long stems for bouquets, cut the stem down within a few inches of the ground.   It'll take the plant longer to recover but you'll have taller floral spires.

DON'T WANT TO DEADHEAD?  

Looking to simplify your garden maintenance or just don't want to bother with deadheading? Here are five annuals and four perennials that look fine without having their spent flowers removed.

   Annuals                                                    Perennials

•

• Bidens Bidens ferulifolia                         • Old-fashioned bleeding heart

• Calibrachoa Cafibrachoa hybrids                Lamprocapnosspectabifis

• Fanflower Scaevofa hybrids                    • Peruvian lily Afstroerhea hybrids

• Nemesia Nemesia hybrids                       • Russian sage Perovskia atitplis;jfofia

• Vinca Catharanthus roseus                    • Woodland phlox Phlox divaricata laphamii