November completes the fall transition begun in October. Still-warm days become dark evenings with consistent frost. The month brings the average first date for “cat-tracking” snow (measurable snow), transforming our gardens and our tasks. Seed harvesting continues through the month, if conditions are dry enough. Fallen leaves from trees and shrubs provide mulch to prepare beds, protect plants, and amend garden soil. Leaves can be piled in out of the way places, and a light layer of non-matted leaves can be left on lawns. You can store leaves for next spring in thick layers on an unplanted bed. If you use leaves from your own yard, you can ensure that invasive species and weeds are not in the mix. Our leaf mulch contains mixed species (oak, maple, locust, hickory, cherry, and more), all of which compost well.
In the native plant garden, we do not remove leaves from the beds or trim back dried stalks in fall—this provides color, texture, seeds, and wildlife habitat for the winter months. Mixed flocks of goldfinches and sparrows feed on the seed heads of grasses and forbs. Voles and rabbits live in garden beds where dried plants are thick enough to provide cover. Invertebrates may overwinter in standing plant material or in fallen leaves.
Where are some of our familiar garden invertebrates this month? Silver-spotted skipper (Epargyreus clarus) larva feed on legumes during the summer and shelter in curled leaf nests, where they mature and pupate. This month the pupal stage is dormant, wrapped in the leaf on still-standing stems or on the ground nearby.
The viceroy butterfly (Limenitis archippus) overwinters as a third instar larva, having fastened itself to a leaf and stem of willow (or other member of larval host family Salicaceae). As the willows leaf out early in spring, the larva feeds and completes its development. This month the cryptically colored larvae are dormant on standing twigs.
Black and yellow garden spiders (Argiope aurantia) build their webs 2–3 feet off the ground. In the summer, the female lays eggs in a brown papery case attached to her web. The eggs hatch in the fall, but the spiderlings do not emerge until spring. In November, the egg case is still on plants or in fallen leaves and plant stems.
In our area, giant swallowtail butterflies (Papilio cresphontes) use prickly ash as a larval host plant. After developing during the summer, the larvae attach themselves with silk strands to a vertical stem and pupate. This month the large but inconspicuous mottled gray chrysalis is “harnessed” to woody brush.
Because common buckeye butterflies (Junonia coenia) migrate in the late summer and may return to northern latitudes in late spring, the adults are only rarely present in our gardens during November. Plant hosts are diverse, including these families: Orobanchaceae (many parasitic and hemi-parasitic plants in this group), Plantaginaceae (plantains), and Verbenaceae (vervains).
The Xerces Society for Invertebrate Conservation lists a few more examples in “Leave the Leaves.”
Our native plant gardens are full of life, even during dormant seasons, if our gardening practices follow nature’s seasonal patterns.
—Susan Carpenter, Arboretum native plant gardener