I planted a perennial garden several years back. In the past two years, the Shasta daisies have spread and are taking over the whole garden. I have dug several up but the roots are numerous. Should I just spray them to kill them?
When you read comments about Shasta daisies on garden websites, it’s clear that gardeners either love them or hate them. Love them because these daisies (Leucanthemum, in botanical nomenclature) are easy to grow and bloom reliably year after year; hate them because they can be aggressive and can, indeed, muscle out plants that are more well-behaved.
Spraying is risky, and I never recommend it. I assume you’re thinking about using something like Roundup or other weed killers that contain glyphosate. It would most likely kill the daisies, but since it’s a non-selective herbicide, that means it will kill or damage everything else it happens to drift onto. Plus, the ingredients in these products have been found to have adverse health effects. I wouldn’t recommend using it. If you decide to try it, be sure to follow directions on the label.
In my own garden, the daisy bed is encroaching on a patch of ‘May Night’ salvia, a small new hydrangea and a prized peony, but it’s a small enough patch that I can dig up or rip out about half of it every year and that keeps it within its boundaries. Daisies are tough and long-lasting. You can be ruthless in your digging and dividing, and they seem to always come back stronger. A few years ago, I dug up and mailed plants to a gardening friend at the other end of the state, and she reports that they are doing just fine.
I keep them around because they are so reliable, have a long blooming period, and are perky and cheerful in the mid-summer heat. My garden gets less than full sun where the Shasta daisies are planted, but they tolerate the lightly shaded conditions and bloom well. Butterflies love them, and they are great as cut flowers because they last a long time in a vase.
If you no longer want the daisies, you could also dig them up and dispose of them, unless the patch is so large now that it’s an impossible task. How about inviting gardening friends over to dig up what they want and take them out of your garden?