Well, she had a point. The annuals and perennials in the garden are at eye level. Of course that is where we see the majority of butterflies. However, if we look more closely and do just a bit of research, we learn that native trees contain some of the most important sources of food for wildlife, including many Lepidoptera species. In almost any list recommending host plants for butterflies and moths, many native trees are included.
The best scenario for a butterfly garden is to have plants at all levels of strata, beginning with groundcovers, annual and perennial flowers, shrubs, vines, and finally, at the upper level, trees. It is true that many annual and perennial flowers are host plants for butterflies, and they certainly are important components of our gardens. Think about the monarch and its dependence on milkweed; the Eastern black swallowtail and its dependence on the Apiaceae family. However, trees support myriad species.
Trees are important for butterflies in other ways, too. Not only do many species lay eggs and feed their caterpillars on certain trees; they provide shelter and places to overwinter for many more species. In one report, trees provide larval food and nectar for anywhere from 100 to 500 species while most perennials provided these services for about 30 to 40 species.
Not to disregard the benefits of blooming wildflowers, annuals, and perennials to pollinators, but let us not forget that one large, flowering tree offers a whole garden of flowers. Many of them, especially if they are native trees, have the added benefit of hosting many Lepidoptera species as well as hosting other insects important to birds and other wildlife.
Some of my friends dislike bugs and do not want to see them in their gardens. I ask them, “Do you enjoy seeing birds in your garden?”
They reply, “Of course. I keep bird feeders and birdbaths filled in order to attract them.”
My friends have not realized that the most important component of birds’ diets are insects. A mother bird does not feed her young seeds; she feeds them insects. Simply put, you can’t have birds without insects. In addition, the insects support a host of other species, such as rabbits, lizards and anoles, foxes, frogs, and the list goes on.
I’m no expert on trees outside the South, but Douglas Tellamy recommends several native trees of value to wildlife that also have desirable landscaping attributes for various regions of the country in his book Bringing Nature Home. His list of trees for almost every part of the United States includes various species of oak, maple, birch, hickory, persimmon, beech, ash, hickory, tulip tree, blackgum, sourwood, cherry, oak, sassafras, juniper, and many others.
Of particular interest was his report of the work done by Kimberley Shropshire, his research assistant. She put together a list of woody plants ranked by their ability to support Lepidoptera species. The numbers are amazing. Oaks top the list with 534 species supported; next came willow with 456, cherry and plum with 456, birch with 413, poplar and cottonwood with 368, crabapple with 311, maple and box elder at 285, elm at 213, and the list goes on. One becomes aware that almost every native tree is useful to wildlife.
Many will argue that birds eagerly eat the berries of the exotic species in their gardens. This is so; they do. We know that migrants consume any berries they can find as they prepare for their migrations, and that all birds eat berries during the long winter months. Notice, though, that when birds start making nests and raising their young, it is insects they look for and need. Then again, we remember that native plants are primarily the ones that feed our native insects, and consequently, our native birds.
Notice, too, that Tellamy’s recommendations are for native trees – not those from other countries. He maintains that insects have evolved with native trees for eons and often do not recognize non-native trees. For many insects, a plastic yard ornament would be as useful as a non-native tree.
The take-home lesson is that trees are very important, not only to butterflies, but to all wildlife. Native trees are the ticket to more birds, more butterflies, more wildlife of all kinds, and for humans, more enjoyment as we take pleasure in the wildlife supported by native trees.