Deadheading, with or without Jerry Garcia

When flowering gets sparse, it’s time for a haircut. — Jim the Photographer/Creative Commons

New gardeners often react with alarm because their annuals — which they understood would flower all summer long — have stopped blooming.

It’s not hard to guess what’s happened. Annuals move at breakneck speed from the frail seedling stage to maturity, which occurs with a huge flush of bloom. Garden centers love to sell hanging baskets of geraniums, petunias, verbena and such when they are at this point of maximum profusion.

But annuals have an agenda that has nothing to do with you and your flower-hungry ways. Subscribing to the live-fast-and-die-young philosophy, they want to grow, bloom, set seed and die. If you leave the spent flowers in place, nature will take its course.

Pollinated flowers will fade away, leaving behind pods in which seeds develop and ripen. When that happens, your annuals will feel they have fulfilled their destiny and will usually start to flag, turn yellow and give up the ghost. This can happen long before you’ve gotten your money’s worth from those increasingly pricey planted containers and hanging baskets.

To get more bang for the buck, you can step in and dupe the plant into believing its mission in life has been aborted. You do this by removing spent flowers promptly, a process called “deadheading” that has nothing to do with the late Jerry Garcia, the Grateful Dead or the followers of that merry band.

Your annuals will think their flowers have met with misadventure — and would make no distinction between your pruning shears and the hungry maw of your backyard rabbits and woodchucks. In its own little plant way, it will shrug, accept fate and get down to the business of producing new growth, new buds and new flowers, all in a quest to assure survival of its kind via incipient offspring, i.e., seeds.

Trim snapdragons for a new flush of bloom. — Cross Duck/Creative Commons

What deadheading means for the gardener is a longer season of bloom from annuals like zinnias, petunias, snapdragons, marigolds, dahlias, lantanas and salvias. Of course, for every principle there are exceptions.

Some annuals are actually “self-cleaning,” with flowers that drop off on their own with no help for you — these include impatiens, portulaca, sweet alyssum and ageratum or “floss flower.” Some fancy hybrids will keep blooming whether you deadhead or not because they are genetically sterile, and therefore can’t set seeds.

Most hybrid plants do not duplicate themselves or “come true” from seed, anyway, so there is no point saving either seeds or self-sown offspring. Other, simpler annuals without named varieties will self-sow charmingly if you leave a few seedheads intact — love-in-a-mist (Nigella), sweet alyssum and annual poppies to name three.

When deadheading, it is not enough to merely pluck off the wilted petals. You should cut back or pinch off the flowering stem at the nearest leaf, where new growth will develop. This is not only horticulturally correct, but will improve the scenery in your garden by removing both the spent petals and the now useless stem.

For plants that bear too many little blossoms to deadhead individually, opt for shearing. Using a grass clipper, cut the entire plant back by at least a third when blooming wanes. This sounds dicey and the plant does look at first like it has had a bad haircut, but with a shot of fertilizer and regular watering, it will soon recover and be blooming once more.

Some plants are so attractive to bees that it’s hard to get a shear in edgewise. The solution is to wait the little buggers out, since they do go home at night. I just sneak out to the garden in the last light of dusk to whack down my lavender and ladybells, which otherwise are humming all day long with honeybees, bumblers and butterflies.

By midsummer, deadheading chores in a large garden can seem overwhelming, which is why it is best to do a little at a time every day, working your way sequentially through garden beds and containers. Far from being odious, this is an opportunity to get up close and personal with your plants, and you may find as I do that deadheading is a perfectly soothing mindless chore. If you can hum “Truckin’” or “Sugar Magnolia” as you work, so much the better.