If you’re a gardener, that word means something to you, and it has nothing to do with Jerry Garcia. Deadheading means cutting off flowers that are fading, which encourages the plant to bloom again. I’m writing this in summer, which is high season for deadheading. Flowering plants invest a lot of energy into making seeds, and although I cringe to write this next part, it’s the truth – as gardeners we want to thwart that process. Most plants form flowers that will be pollinated, then dry, shrivel and release seeds, ensuring that the plant reproduces itself. We gardeners interrupt that cycle by cutting off the flower. The plant responds by trying again - making new flowers. It makes me feel a little guilty to say that, but then again, I’m ensuring a future for my plants by growing them again and again every year.
There are times when it isn’t appropriate to deadhead. Some flowers won’t bloom again, whether you deadhead or not. Flowers from bulbs and corms are in that category: tulips, daffodils, iris, ranunculus, anemone, hyacinth and crocus. And there are times when you want the plant to form seeds. In my own garden, there are a few annuals that “self-seed” and come back the next year if I let them. Self-seeding is the norm for most plants in their natural environment, but many hybridized flower species won’t shed viable seeds; those that do are said to “self-seed.” Omphalodes, Cerinthe and Nigella are good at self-seeding in my garden, so after one or two rounds of cut flowers I stop deadheading and let the last flowers go to seed. The following spring I’m rewarded with new plants that I didn’t have to buy or plant.
Roses benefit from deadheading more than almost any other plant in the garden, assuming we’re talking about modern, re-blooming roses. Most of the roses you buy in the nursery are in this category. They put out a big flush of blooms in the spring, but if you cut off all those flowers (as you would in making bouquets) the plant will send up more buds. Depending on the rose variety, this cycle can repeat four or more times before winter. We deadhead our roses religiously, so we have blooms for three out of four seasons. Different varieties re-grow at different rates, so flowers come at different times. I once deadheaded all my roses at the same time then recorded the dates of the next set of blooms. ‘French Lace’ bloomed again three and a half weeks later, taking first place in the flower race. ‘Gold Medal,’ ‘Pink Promise’ and ‘Julia Child’ were close seconds, blooming again after about four weeks. ‘Outta the Blue’ was quite slow, taking almost six weeks, as did many others. But results would vary with season, temperature and water, so these are only amusing observations, not hard facts. I’ve heard it said that in Northern California you can deadhead your roses on the first of October and have blooms for your Thanksgiving table, but in reality, that will depend on which varieties you’re growing. Which comes back to advice I’ve given before in this blog: pay attention! Observe your own garden, keep notes, take photos, then learn from all those observations. The key to growing a successful garden is to pay attention!