If you’ve been reading our blog, you are aware of the importance of leaving the leaves where they fall. To recap, leaves are an essential piece of our local ecosystems – not trash to be carted away. They provide nutrients to the soil underneath as they break down while creating shelter for pollinators, insects, and other wildlife through the winter.
There is another fall task best left undone – cutting back the perennials and grasses in our gardens. Not only do these tasks create a lot of work for us, they have many environmental drawbacks. When done in conjunction with leaving our leaves, leaving our perennials and grasses standing is a more sustainable way to care for our landscapes with numerous benefits for birds, pollinators, and other insects. Today let’s focus in on another one of these benefits – water conservation.
Here in central New York, we are very familiar with urban runoff and flooding. One way we can reduce the compound effect of urban runoff is to keep rainfall on our property for longer allowing it to soak into the ground. The concept of effective rainfall is familiar to farmers and ranchers, but can also apply to us on a smaller scale. This illustration shows some of the elements that can help us better use the rain that falls on our landscapes.
Effective vs Non Effective Rainfall
We know that healthy soils grow healthier, more resilient plants, but we might not realize heathy soil also increases the land’s ability to resist both drought and intense rainfall. When the soil can’t hold much water, runoff, erosion, and evaporation increases and the soil loses nutrients and becomes compacted and more vulnerable to drought over time. In healthy soil, there is a whole world of microorganisms working to turn leaves and other organic matter into nutrients which in turn feed our plants and create the structure necessary for soil that can hold water and resist runoff.
As shown in the above illustration, the plants in our landscapes hold water too. The stems and leaves capture and slow the rain as it drips to the ground below. Standing plant stems and debris also prevent the water from rushing away when it reaches the ground, allowing time for it to soak in. Leaving those stems and seed heads standing throughout the winter gathers and holds snow, which is then slowly released into the soil as it melts in the spring. The more water the soil is able to absorb in the rainy months, the more resilient the ground will be through the dry months. This has the double benefit of reducing the amount of irrigation our gardens will need in the summer – saving us time cleaning up in October and watering in July.
Much of the debris we leave standing will fall over and start to decompose on its own. You could leave this plant material as a natural mulch. In the spring, leave some of the stems that are still standing and cut them to varying heights from 12″ to 18″ for native bees to nest in. Those stems will be hidden by new growth in a few weeks. For the rest, or if you need sun to reach the dirt to germinate seeds, wait until the soil reaches a temperature of 50 degrees. That’s when wildlife overwintering there will start to wake up.
If our home landscapes held more water, less water would run off into the streets and overwhelm our stormwater systems, or into our streams and rivers causing flooding downstream. Leaving the leaves where they fall and the stems where they stand is one way we can accomplish this.
This is what sustainable gardening or land management is all about – creating more resilient, self sustaining landscapes that require less input and maintenance from us. At Olmsted City, we will be following these practices at the park in our efforts to both increase the health of the landscape and reduce the maintenance required.
See our blog posts from October and November of 2022 for more on the benefits of leaving the leaves.
For more on effective rainfall and how to maximize it, read this blog post from TomKat Ranch, a regenerative ranch in California – www.tomkatranch.org/effective-rainfall-putting-all-that-wonderful-rain-to-good-use/
Illustration Non Effective vs Effective Rainfall by the Savory Institute, a non profit working towards large-scale regeneration of the world’s grasslands.
