Spring in the Garden !!
By: Jo Doumbia
As our weather warms up, we gardeners start looking outside to see what we can do to prepare for spring. Garden clean-up is one of those tasks that we often set about doing; but what is garden clean-up, and should we really be removing dead stems, dead branches, and dead leaves? Here the views of several ecological horticulturists about garden clean-up and how much they do:
Pawel Pieluszynski, from the Brooklyn Bridge Park, says that as spring approaches, it’s time to prepare the garden for all of its fresh new growth. Dry perennial stems that have been left up for winter interest (or “winterest” as he likes to call it) and food sources for overwintering birds can still have enormous ecological benefits in this oncoming growing season. In years past, the standard practice was to hack these leftover stems all the way to the ground. He adds, that as we now know, these old stems are ideal breeding habitat for stem-nesting bees and a variety of other insects. Thus, these stems can be cut down to a height of around 12 to 18 inches and be allowed to persist throughout the year to facilitate healthy insect biodiversity in yards and gardens. Leaving these small stem fragments has added benefits, as they can still contain overwintering insect larvae and pupae which can then continue to develop and emerge later in the spring.
Leslie Duthie, a Native Plant Horticulturist says that as a full time horticulturist retiree, she is beginning to rethink what her garden cleanup looks like. She usually rakes the leaves off the lawn and put them in the beds in the fall. She used to shred them with her lawn mower, but she realized they are ok to leave whole. The leaves break down over the winter and plants have no trouble popping up through those leaves in spring. She leaves the old stalks of her native meadow standing until late April and early May. She uses the brush cutter, pruning shears, or a rake to knock down the old stems, but leaves them in the garden as the dead material breaks down and will enrich the soil over time and leaving the stalks and stems whole will allow any hibernating insects or insect eggs and larvae to complete their life cycle and move into their next stage of growth.
Leo Kenney, an Ecological Horticulturist says that he takes a very relaxed approach to garden cleanup. In the fall, he leaves all standing vegetation, except irises to prevent iris borer infestations, as plenty of nameless insects live in spent flower heads, feasting on the remaining seed or on each other, offering a little protein for winter birds to forage.
In addition, tall-standing hollow stems make great overwintering habitat for a great diversity of native solitary bees, and giving those bees upright stems to live in keeps them, hopefully, away from all but the most persistent garden rodents who might make short work of tasty grubs at ground level. He makes a point to leave leaf litter in place whenever possible, since plenty of moths pupate there. He also says that his garden looks a little skeletal in winter, but he takes comfort in knowing that many small lives are persisting out there in the cold.
In spring, he doesn’t initiate any cleanup until most insects have awoken and emerged. According to The Xerxes Society, it’s best to wait until nighttime temperatures are regularly in the 50oF-55oF range to cut back last year’s stems. Sometimes, he leaves the cut material scattered in the garden (if it’s not too dense), permitting it to decompose in place, but when there’s so much on the ground that new growth might be smothered, he creates little bundles or piles from the cut stems and leaves, which he tucks away at the back or edges of the space. He strives for creating a thriving habitat rather than a conventionally beautiful garden since as he says, there’s plenty of beauty for those who know how to look.
Should we then be concerned about these insects? In my, and many others’, opinion they provide food for larger insects, mammals, birds and may even provide some beauty in the form of beetles, butterflies, moths, bees and wasps. By attracting species to native plants and leaving sites for nesting and cover, our yards become havens for wildlife and provide longer enjoyment times.
Photo By: Jo Dumbia