Put Down Those Pruners: Pollinators Need Your ‘Garden Garbage!’

By - Web & Communications Specialist

Published on October 21, 2016
Tags: , ,

It should be welcome news for weary gardeners. You’ve weeded, tilled, and toiled under the hot sun all summer long, and now — it’s time to stop. For many, however, the temptation to pick, pluck, and prune the landscape to make it neat and tidy for the winter is too hard to ignore. This impulse to “clean up our gardens for fall” has serious impacts on a whole host of pollinators and beneficial insects. All it takes is a weekend and some garden tools to wipe out whole populations of insects who have been hard at working hard in your yard all summer too – provisioning their nests and making well-stocked winter homes for the next generation.

To Every Season…

Insect pollinators spend the winter in a variety of life stages (egg, larva, pupa, or adult) depending on the species. For example, native bees will have spent their lives in your garden drinking nectar, collecting pollen, and building their nests amongst your fruits and flowers. After hatching, the “new” bees will spend the winter in their nest cells as pupae, emerging as adults the following spring or summer. Lather, rinse, repeat.

This is why timing is critical. Habitat needs to be protected year-round.

peponapis_pruinosa_male_elsa

70% of bees are ground nesting, like this squash bee which will nest 6 to 8 inches beneath the soil surface – right beneath the summer squash, zuchinni, and pumpkins you plant. Photo by Elsa Youngsteadt CC BY-NC – 4.0

Cut down the stalks and stems bees are nesting in too soon in the spring, or while the bees are settling in for the winter and it’s game over for your pollinator pals. Apply a thick layer of wood mulch over the top of ground nesting bees (70% of native bees are ground nesting), or till your garden in spring or fall, and you’ve wiped out your best allies including bees who emerge early in the spring to pollinate tree fruit and squash bees that live just beneath the surface of your garden and pollinate your pumpkins with aplomb!

Leave Leaves Bee

Unlike other native bees, bumble bees do not overwinter in their nests. Instead, new bumble bee queens emerge from their childhood homes in the fall and search for overwintering sites, burrowing into leaf litter and loose soil. See above re: mulching/tilling.

Leaf litter, with its mix of bacteria, fungi, and invertebrates is an ecosystem unto itself – providing habitat for beneficial insects who in turn break the organic matter down into “garden gold” providing nutrients back to the soil. What we call “leaf litter” provides a wealth of overwintering habitat for invertebrates including slugs and snails, worms, millipedes, centipedes, spiders, beetles (and much much more!) If you have children, this can be a great opportunity to engage them in a little Citizen Science – a great way you can both enjoy the fall leaves!

This eastern black swallowtail pupae does a great job blending in with the landscape, looking like a dried leaf or bit of plant material to the casual observer. Photo by Mary Anne Borge, The Natural Web

This eastern black swallowtail pupae does a great job blending in with the landscape, looking like a dried leaf or bit of plant material to the casual observer. Photo by Mary Anne Borge, The Natural Web

Hidden in Plain Sight: Butterflies and Moths

For butterflies and moths, overwintering is even more complex. Lepidoptera overwinter in all manner of life stages depending on the species. Fritillary butterflies who host on violets spend the late days of summer “sniffing out” violets with their antennae and laying eggs. The emerging larvae hide out in leaf litter, waiting for the plants to emerge the following spring.

The eastern black swallowtail (Papilo polyxenes) spends the winter as a pupa, hidden to all but the most scrupulous of observers camouflaged as a dried leaf or a broken off twig. It would be quite easy to miss when clearing canes and dried plant material from your garden.

We all know that monarchs migrate, spending their winter days as adults in Mexico and along the California coast, but did you know the resilient mourning cloak (Nymphalis antiopa) stays home, toughing out the winter between bark, in piles of dead wood, or in your garden shed?

We hope you’ll see, far from a dead and desiccated landscape, the fall and winter garden is teeming with life.

Fall Cleanup Do’s and Don’ts:

Put your feet up, the pruners down, and grab a Pumpkin Spice Latte. Don’t cut canes, stalks, or other standing plant material which may house nesting bees or be providing anchors for overwintering pupae.

Where possible, leave leaves alone. If you must clear them from lawns and other areas, do not bag them and send them to the landfill – try to find ways to put them to work!

Do not till soil where there might be ground nesting insects.

Provide safe havens by setting aside undisturbed patches of habitat allowing leaf litter, standing dead twigs/stems, or other ground cover to remain. “Wild”, unmanicured locations will provide the protected nooks and crannies that pollinators and other animals need for survival.

If you must clean up your yard to comply with Homeowners Association rules or other local ordinances, consider sharing this blog, starting a conversation, and putting up a Pollinator Friendly Habitat sign to advertise to the world that your “messy” garden is intentional habitat (pardon the shameless plug).

Don't rake away critical habitat! Your "messy" garden can support a bounty of beneficial insects all year long. Photo by the Xerces Society / Matthew Sheperd

Don’t rake away critical habitat! Your “messy” garden can support a bounty of beneficial insects all year long. Photo by the Xerces Society / Matthew Sheperd


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