Great rock garden plants, eliminating grubs and moles
Lamium is a ground cover that would be at home in the rock garden. Credit: Missouri Botanical Garden Plant
DEAR JESSICA: I have a rock garden in the front of my house. I never know what kind of plants to put there. It gets full sun in the morning until 3 p.m. My rocks are large, so I need about eight plants. What do you suggest?
— Jo Ann Flaccomio,
Plainview
DEAR JO ANN: Rock gardens typically are home to low-growing, drought-tolerant plants that grow in shape and form to complement the stones that define their bed. Alpine plants, such as cushion plants, mosses, dianthus, Phlox, Sedums and Sempervivums are commonly used in rock gardens.
Pleasing combinations to consider are Aubrieta, Gypsophila (baby’s breath), Phlox, Potentilla and Dianthus. For a larger area, add some ornamental grasses, Yucca and creeping cedar. Red creeping thyme also can be used to fill in bare patches and is lovely when it cascades over stones.
I also especially like ice plant, woolly thyme, hens and chicks, snow in summer, lesser periwinkle, soapwort “Max Frei” and lamium.
DEAR JESSICA: My beautiful garden is being destroyed by moles. They gradually are eating the roots of my every plant, large or small. I really need help.
Woolly thyme elegantly fills in bare patches between plants in the rock garden. Credit: Missouri Botanical Garden
— Christine Stluka,
Sag Harbor
DEAR CHRISTINE: The good news is that moles aren’t actually eating your plants’ roots; moles don’t eat plants, they eat grubs. The bad news is the reason you have moles is because you have grubs, and grubs are eating your plants’ roots.
This isn’t to say moles are completely harmless. Although they’re serving a noble purpose by decreasing the grub population, they’re probably disturbing your plants as they hunt for their dinner, and leaving little mounds of soil in their wake.
Soapwort plants, like this Max Frei variety, grow nicely in rock gardens. Credit: Missouri Botanical Garden
There are many mole-control products on the market, from fumigants and baits to insecticides aimed at eliminating grubs and, thus, killing off moles’ food supply. None are especially effective, and some are harmful to the soil, environment, humans, pets and wildlife. Traps are available, too, but they shouldn’t be necessary. Your best course of action would be to eliminate the grubs. When they go, the moles will move on in search of food elsewhere.
First, confirm that you actually have a grub infestation. Dig up and peel back a 12-inch section of lawn or garden bed soil, a few inches deep, and peer beneath it. Grubs are white to off-white, brown-headed beetle larvae that look like curled-up shrimp. Ten grubs per square foot is the tipping point that typically triggers the need for control.
Because of their life cycle, it’s important to treat vulnerable stages of grubs at the right time. Eggs hatch in August, and baby grubs begin feeding on roots shortly after birth, so mid-August through mid-September was the ideal time to target them in order to reduce or eliminate the coming spring’s population. You would have watered the garden to attract grubs to the surface, then applied a grub-control product that targets young grubs, according to package directions, then watered again.
Since you missed that opportunity, however, your next shot at control would be to target eggs during the third week of June with a pesticide containing the active ingredient Imidacloprid.
