We hear a great deal about pollinators and insects in the spring and summer, but we seem to forget about them come fall and winter.
As autumn approaches, many of us think about garden clean-up. The expression “putting your garden to bed” is often used when we talk about making gardens look tidy for the winter. Getting rid of all the leaves, cutting back all the perennials and pulling out the annuals are usually at the top of the to-do list.
However, pollinators, insects, and birds need habitats all year round. Here are a few things we should know about these critters and how to support them during the harsh winters we often experience.
Most people are familiar with the amazing migration of the monarch butterfly that flies south for the winter. However, most butterflies do not migrate; they remain in cold winter areas in one of their life stages: egg, larva, chrysalis, or adult. Some spend the winter as caterpillars, and some stay in the chrysalis stage. A few butterflies overwinter as adults in diapause.
Many native bees hibernate, while honey bees overwinter in their colonies. Northern cardinals (Cardinalis cardinalis), black-capped chickadees (Poecile atricapillus) and blue jays (Cyanocitta cristata) are common birds that do not migrate but remain here for the winter.
The caterpillars we see in autumn need a pile of fallen leaves to overwinter. Some beneficial insects need the stalks or stems of plants on which to lay their eggs. Ground-nesting bees need some loose soil and leaf litter to survive the winter. The cavity-nesting bees lay their eggs in hollow-stemmed plants or holes in wood. The non-migratory birds need food during the winter and protection from the weather.
Consider these autumn activities to conserve pollinators, insects, and birds:
• Leave some of the autumn leaves in the yard. They serve as great mulch in flower beds and vegetable gardens and provide great winter bedding for the great spangled fritillary butterfly caterpillars (Speyeria cybele) and the woolly bear caterpillars (Pyrrharctia isabella).
• Save the stems. Small carpenter bees (Ceratina spp.), mason bees (Osmia spp.), yellow-faced bees (Hylaeus spp.) and leaf cutter bees (Megachile spp.) are among those bees that carve out their nests inside dry hollow stems and spend the winter there. The mason bees are among the first pollinators in our fruit tree orchards each spring. A praying mantid lays her egg mass on sticks and stems of plants. Black swallowtail and tiger swallowtail butterflies (Papilio glaucus) spend the cold months as chrysalids, often attached to a plant stem.
If you must deadhead flowers but still want to support pollinators and other insects, leave eight to 24 inches of stem above the ground. Some native plants with hollow stems include stonecrop (Sedum ternatum), bee balm (Monarda spp.), lupine (Lupinus spp.), Joe Pye weed (Eutrochium spp.), rose-mallows (Hibiscus spp.), and milkweed (Asclepias spp.).
• Leave the seed heads. The birds will thank you for leaving the seed heads from sunflowers (Helianthus spp.), asters (Symphyotrichum spp.), black-eyed Susans (Rudbeckia spp.), coneflowers (Echinacea spp.), and goldenrod (Solidago spp.). The seeds from these plants provide nutrition for feathered friends during the winter months. Tying the stalks together in an upright position makes an attractive winter display.
• Leave or make a section of loose undisturbed soil. The queen bumble bee (Bombus spp.) overwinters in loose soil, as do the majority of native bees. The loose soil should be in a sunny spot that does not retain water.
• Build a brush pile. Another hibernating site for some butterflies and many beneficial insects such as fireflies (Lampyridae) is a pile of twigs, old wood, logs or bark. The pile should be elevated at least six inches and provide plenty of air space. Chickadees and other small songbirds enjoy the hiding places provided by the branches. Construct the brush pile in an inconspicuous yard area, as some neighbors may view it as unattractive.
• Build a rock pile or rock wall. Whether it be just a rock pile or a neatly constructed rock wall, a habitat for a diverse group of beneficial insects is present. Leafcutter bees, bumble bees, ground beetles (Carabidae) and other beneficial insects live or shelter in the crevices between the rocks and the soil and the stones.
Judy Coleman is a Penn State Extension master gardener. Penn State Extension is dedicated to delivering science-based information to people, businesses and communities. They partner with and are funded by federal, state and county governments. For more information on what they’re doing in Lackawanna County, visit extension.psu.edu/lackawanna-county.
According to the Xerces Society, “one of the most valuable things you can do to support pollinators and other invertebrates is to provide them with the winter cover they need.” These suggestions should inspire you to become a habitat-friendly gardener by saving some of the clean-up until spring.