Between the two raspberry beds in Marjorie’s Garden, an old stump slowly rots. It began rotting in this place long before the day 12 years ago when I first came to this garden. Some portion of it will likely be there 12 years hence, if mostly underground. Over the years, soil slowly sifted into the stump’s hollow center where fruiting raspberry suckers now grow. In the shade of these raspberry canes, moss clings to what is left of the old stump’s wood and ferns grow along the border where decaying wood meets soil.
The shade ends within a foot or so of the old stump and there, many years ago, Marjorie transplanted a few Cerastium tomentosum, snow-in-summer, and now there is a colony of this herbaceous perennial covering the ground between the raspberry beds. Through June, the six-inch-tall carpet gray-green tomentose foliage is covered with bright white flowers, each with five notched petals.
I was in this section of the garden this past week, working until twilight. As the sun dropped behind the distant spruce trees, the snow-in-summer flowers glowed, returning the captured sunlight of afternoon. Small solitary bees and hoverflies foraged the flowers as they swayed in the breeze while darkness settled over the rest of the garden.
Native to Europe and western Asia, non-invasive, and hardy in USDA Zones 3-7, C. tomentosum is a perfect groundcover for full sun sights where the soil is dry and rocky. Deer and rabbits leave it alone. It’s only bane is soggy soil and it is bound to die out in areas with poor drainage.
Colonies of snow-in-summer gradually increase in size by vegetative runners and self-sown seed. When a colony starts to exceed its boundaries, the plants can be easily dug and divided in spring or fall. To prevent self-sowing of seed, remove the spent flower stems by shearing or mowing.
Cultivar selection in C. tomentosum has been directed at reducing plant height, enhancing foliage color, and improving foliage color. ‘Silver Carpet’, for example, has frosty white foliage, a compact habit, and less aggressive growth. ‘Columnae’ is similar but with lower, four-inch mounds of foliage. ‘Yoyo’ is also more compact and less aggressive.
Many gardeners are taking advantage of snow-in-summer’s aggressive growth habit and using it as a replacement for turf grass. It has the necessary stress resistance and is tolerant of light foot traffic.
For much of June, the most conspicuous plant in our island perennial bed has been meadow rue (Thalictrum aquilegifolium). The species name refers to foliage that resembles that of columbines (Aquilegia sp.). Meadow rue’s tall clusters of petalless male flowers resemble balls of pink fluff, the color coming from the stamens. Female flowers are far less showy.
The absence of petals does not deter pollinators from at least visiting this plant. While watering a nearby plant in the same bed, I came face to face with a sphinx moth and was able to watch it as it foraged over the meadow rue’s ball of stamens.
Meadow rue is typically not bothered by deer.
Chives (Allium schoenoprasum) bloom in June, their balls of pale purple flowers swaying under the weight of bees gathering nectar. I grow them as much for this ability to attract a host of different pollinators as for their tasty stems.
One of the earliest June-flower perennials in Marjorie’s Garden is the mountain bluet (or mountain coneflower), Centaurea montana. Native to central and southern Europe, it is a stoloniferous clump-forming plant noted for attracting bees and butterflies to its fringed, rich blue flowers, each with a reddish-blue center and black-edged bracts.
C. montanais easy to grow in a full sun site with well-drained soil. It is drought
tolerant. Over time it will spread to form colonies, particularly in cool northern gardens where it is more robust.
Finally, let’s not forget the self-sowing volunteer that flowers in June, johnny-jump-ups (Viola tricolor). They add a touch of color to the perennial bed and vegetable garden, wherever they appear, as well as a mild wintergreen flavor to salads, soups, and desserts.