November quiets the garden. Growth stops, seeds scatter, dormancy begins or continues. By month’s end, we may see snow that sticks. At the Arboretum, we leave the native plant garden untrimmed for the winter. We encourage this practice in home gardens to leave seeds for dispersal, sites and nesting material for native birds next year, and winter cover and nutrition for small animals. Dried plant material protects soil from erosion and, in some areas, fuels next spring’s prescribed burns. An untrimmed garden invites a closer look at plant shape and seed arrangement. Vegetation and soil harbor overwintering pupae, eggs, and even larvae and adults of various native insect species, ensuring their ecological roles.

November is an ideal time to protect garden life by using fallen leaves to create “soft landings” – beds under trees where turf grass won’t grow well but shade gardens thrive. In addition to retaining nutrients in your yard, dormant insect life stages are protected there. For example, during summers we observe two sphinx moth species, hummingbird clearwing moth (Hemaris thysbe) and snowberry clearwing (Hemaris diffinis). During flight season they are active during the day, hovering to nectar on honeysuckle (Lonicera spp.), cherries and plums (Prunus spp.), bee balm (Monarda fistulosa), and thistles (Cirsium spp.). They overwinter underground as pupae. This butterfly and moth project is helpful for moth identification.

Viceroy butterflies are another insect that could benefit from “leaving the leaves.” Although they are sometimes confused with monarchs, viceroys overwinter on stalks or in leaf litter, after the larva folds and spins a leaf into a small covering and attaches it to a stem. For statewide information, the Wisconsin Butterflies website includes identification, butterfly seasonality, life history, geographic distribution, and a place to submit your photos and observations.

During November, after flowers have faded, native grasses still stand tall in the garden, especially this year when rains were ample and consistent. Little bluestem (Schizochyrium scoparium) reached four feet in height in some gardens; big bluestem (Andropogon gerardii) exceeded seven feet in others. Grasses provide structure and support for other plants, and seeds and shelter for animals. Their root systems are fibrous, deep, and extensive. Over time they increase the infiltration of rain and melting snow into soils. Native grasses vary in their growth patterns; cool season grasses grow vigorously during spring and fall, and warm season grasses in summer. This month, their fall color and seed heads provide texture and luminosity. They are especially beautiful backlit at low sun angles.

Native grasses are sometimes overlooked for gardens. Consider height, moisture requirements, and shade tolerance to select species for different garden spaces. The seeds of most grass species have no stratification requirement – they don’t need cold, moist treatment. Direct seeding on bare soil or starting seeds in flats next spring will yield small plants when weather conditions allow germination. In semi-shady areas, Canada rye (Elymus canadensis), bottlebrush grass (E. hystrix), silky rye (E. villosus), or prairie dropseed (Sporobolus heterolepis) may grow well. In dry sunny sites where short species are preferred (as along a curb), include purple love grass (Eragrostis spectabilis), little bluestem, prairie dropseed, June grass (Koeleria macrantha), and side-oats grama (Bouteloua curtipendula).

On a practical gardening note, there is still time for pre-winter gardening tasks like creating new beds and “soft landings,” recording observations, and planning changes for the next gardening season.

– Susan Carpenter, native plant garden curator