Gardening with Native Plants: Late Fall

Joe-Pye-weed seedheads

Joe-Pye-weed seedheads

In November, days become shorter and colder. Snow may fall by the end of the month and frosts are common. Now limited to warmer days with mild wind, outdoor tasks include trimming, pruning, seed harvesting. Indoors, I’m summarizing the past season and planning for the next. After a two-year hiatus followed by a successful gardening season in 2022, the native plant garden volunteers are on break until next spring. I appreciate their hard work, enthusiasm, great questions, and keen interest in native plants and garden wildlife.

As winter approaches and the garden goes dormant, we take time to research questions and issues that arose during the growing season. Strong downdraft winds in an early August storm damaged several trees in the maple-basswood forest garden. One large tree fell, breaking at ground level to reveal a possible girdling root that may have weakened the trunk’s support. When it fell, it damaged branches of other large trees nearby. A large limb on another tree snapped down in the wind and broke a small tree nearby. Field staff cut and removed most of the downed wood.

The result is a large opening in the forest garden, bringing more sunlight to the understory plants—herbaceous wildflowers and tree seedlings and small saplings. Species such as pokeweed (Phytolacca acinosa) germinated, as seeds in the seed bank (soil) were exposed to more light. Shade-loving plants quickly showed stress from increased sunlight and heat.

Trunk from fallen tree and trees with yellow fall leaves in maple basswood forest garden
Maple basswood forest garden

Although this is a dramatic disturbance in our relatively small forest garden, windthrow affecting small or large areas occurs periodically in mature forest stands. We are beginning to plan changes and additions to this garden next spring, in response to the new conditions. The most open areas may temporarily look more like savanna than forest as we (and nature) fill in suitable species.

Our gardens also experience smaller scale disturbances from animal activity like woodchuck excavations, turkeys scratching up mulch, leaves, soil or plants, or small mammals feeding on native grass crowns under the snow. Even gardening practices like weeding, edging, and clearing invasive or aggressive native species cause small scale disturbances. Disturbed areas become unsuitable for some species, but other plants may find ideal conditions there for seed germination or growth with less competition.

In garden areas where we use prescribed fire in late spring, fire is a type of disturbance. Many native plants in prairie, savanna, or wetland gardens are stimulated and benefit from the disturbance, growing more quickly in blackened, warmer, nutrient-rich soils. When weeding, we may create bare soils that support persistence of the weeds we are trying to remove. Weedy annual native plants that are adapted to disturbance, like horseweed (Conyza canadensis) or daisy fleabane (Erigeron annuus), can be left (or deadheaded) so that seeds do not fall on bare soils. What types of disturbance do you notice in your garden or landscape?

In the golden or dreary days of November, enjoy reflecting on the past season and consider new perspectives on the next one.

–Susan Carpenter, native plant garden curator