For this gardener August means ripe blueberries and ripening tomatoes, fresh cucumbers every day, the first basil harvest, a river of orange and yellow self-sown calendulas flowing through the vegetable garden. August is stepping gingerly over elephant-ear leaves of winter squash, broccoli seedlings growing on the porch rail, goldfinches pecking at sunflower heads, the fragrance of summersweet blossoms, oak trees with moth-eaten leaves, ripe acorns in the grass.
August brings the lacy blooms of wild carrot. I am fond of Queen Anne’s lace (Daucus carota), ancestor of the garden carrot. Fully aware that it was not growing in North America in precolonial days, I do not believe it is an invasive plant species. Rather, it has gracefully inserted itself into the flora of Maine and other states without, as far as I know, outcompeting native species for resources. It has become naturalized.
Wild carrot is a biennial that flowers in August of its second year, its 3-inch-wide flower clusters (umbels) borne a meter high on stems with ferny foliage. Claret-colored or pale pink before opening, the umbels turn bright white and rounded in full bloom. As flowers give way to seeds, the umbels contract and become concave, look like birds‘ nests. Dried umbels finally detach as tumbleweeds.
Look closely and notice that the rounded umbel is a multibranched structure, each branch bearing clusters of tiny white flowers, the entire arrangement producing a lacy pattern reminiscent of an old-fashioned doily produced by the queen herself. And in the center of most umbels is a single red flower, a blood droplet where Queen Anne pricked herself with the needle; it serves to attract insects.
Wild carrot grows with goldenrod and meadowsweet on the edges of the dirt road leading to our driveway, forming a natural insectary within bee-reach of the garden. On sunny August afternoons I find wild carrot flowers covered with beneficial insects, including lacewings (whose larvae eat aphids and mites), ladybugs, hoverflies, parasitic wasps, bumblebees and solitary bees.
Also blooming in August is the swamp milkweed, a native of Maine swamps and wet meadows, although it is surprisingly tolerant of well-drained garden soils. This erect, clump-forming herbaceous perennial grows three to 4 feet tall with a deep taproot and is best left undisturbed once established.
Swamp milkweed’s flowers, ranging in color from pink to mauve, occur in tight clusters.
They are followed by 4-inch-long seedpods, which split open at maturity releasing silky-haired seeds on the wind. In addition to bumblebees, butterflies forage swamp milkweed flowers for nectar while the foliage is a food source for monarch butterfly larvae.
Both wild carrot and swamp milkweed are pollinated by the giant black wasp, Sphex pennsylvanicus, a species of digger wasp found across North America. For its services, the wasp receives pollen and nectar. I took the time recently to watch and photograph a female (recognizable by her larger size) foraging on swamp milkweed blossoms. For the most part she ignored me and the myriad other insects swarming around, completely absorbed in her work.
She is both beautiful and foreboding, an inch and a half in length, black except for her wings which are a shining metallic blue in the right light. Her heavy-duty mandibles allow her to hang onto her prey, chiefly katydids and grasshoppers that are often larger than her. It is her larvae that feed on these captured orthopteran insects.
The nest, constructed underground by the female wasp, consists of several chambers, each of which hosts a single wasp larva. The female first provisions each chamber with one insect which she has captured and paralyzed with three stings before gluing an egg to its underside. Although immobile, the prey will live until the egg hatches and the larva begins to feed. During its development, the larva will consume between two and six katydids or grasshoppers, so the adult female spends a good portion of her time provisioning each chamber of her nest. (Forget the male, he’s just the sperm donor.)
Not every captured and paralyzed prey makes it to the nest. The female wasp can become a victim of kleptoparasitism (parasitism by theft) by house sparrows and gray catbirds as she drags her prey back to the nest.
August asks the gardener to stop and observe the drama of life within the boundaries of the garden, and to pursue those observations to a deeper understanding of connections between plants, herbivores, predatory insects, birds and the gardener.
Send queries to Gardening Questions, P.O. Box 418, Ellsworth 04605, or to firstname.lastname@example.org. Include name, address and telephone number.