Greetings from the 25th ELA conference in Amherst, MA! ELA stands for Ecological Landscape Alliance and I consider them the Northeast’s authority and best resource for landscapers who aren’t following the conventional methods of business as usual, aka pesticide, herbicide and chemical fertilizer reliance. They are based in Northern Mass, but pull folks like myself from all over the Northeast, Canada and parts of the Midwest for their 2 day conference. I was particularly inspired by a lecture I attended yesterday, given by a scientist who studied the relationship between native plants, birds and pollinators, like bees, butterflies and moths. Her talk was titled “The Chickadees Guide to Gardening” and talked about the scientific research that went into studying the relationship of a population of chickadees in Washington DC with the urban trees there. (Chickadees are one of my favorite songbirds, and are the first bird call I learned to imitate as a kid)
Basically, the talk blew my mind. Its refreshing to spend several hours in the presence of scientists and engineers who can elaborate on the mantras I’ve adopted as an ecological gardener: natives good, non-natives bad/ pollinator-friendly gardens are good/pesticides kill bees etc etc. The above screenshot is from a reference the speaker gave, a website that was the outcome of her research with Doug Tallamy of Mt. Cuba Center in Delaware. The National Wildlife Federation has created a native plant finder feature which you can search by zipcode, and learn what species of plants ( perennials and trees, shrubs and grasses) are native to your area, and get this: it ranks them in order of the number of moth/butterfly species they support! The little butterfly symbol next to the plant photo contains a number. That number is the number of moth and butterfly species that particular plant supports. Goldenrod, which is at the top of the list of perennials, supports 126 different kinds of moths and butterflies! I will never curse this “weed” again, knowing what an important role it plays in our landscapes. Goldenrod, btw, gets a bad rap as the cause of people’s seasonal allergies. While it blooms in abundance and is easy to spot, the real culprit is the nasty ragweed, which blooms at the same time, is inconspicuous with its green flowers, and sprays its pollen into the air (and into our nostrils and lungs). The deal with Non-native species is that they do not attract and support our pollinator species, at least in numbers that support other wildlife, like birds. So, they are basically ignored, like statues in the landscape.
Why care about how many species of moths/butterflies a plant supports when you’re just trying to garden to attract birds? Well, it turns out that songbird’s primary food source are caterpillars, which are the larval stage of moths and butterflies, and without a food source nearby, the bird populations starve and crash. In the DC study, it was found that the chickadees favored oaks, then cherries, then willow species growing among the high rises and residential neighborhoods. It turns out that those tree species (in order of # of caterpillar species supported) are host to moth and butterfly species, which provide the food source so essential to the songbirds.
The big takeaway for me, as a garden designer, was a better understanding of why I should seek out and incorporate native plant species into my gardens, and the National Wildlife Federation’s Native Plant Finder tool, which I can use as a resource when considering what plants to add in client’s gardens and on my own property, or which “weeds” to leave alone and let them spread!