Build a Green-Roof Birdhouse
Two weekends ago, on a beautiful day that was almost spring, I drove down to Longwood Gardens to make a birdhouse. But this wasn’t to be just any birdhouse, as the $90 cost of my birdhouse-making class indicated. My birdhouse would have what’s considered de rigueur in all the latest, most cutting-edge architectural designs: a green roof. Not a roof painted green, mind you, but a living, breathing, rooted roof of plants.
Who could resist the chance to make a green-roof birdhouse? But as birdhouse constructor extraordinaire Dick Gies explained to me and my two dozen classmates at Longwood, the tops to our rustic houses weren’t strictly ornamental. Longwood has been experimenting with bluebird houses in its fields for the past several years, hoping to coax more of the elusive azure beauties onto its grounds. Bluebirds—one of just 250 avian species at Longwood— like the deep, five-inch-square-inside design Dick eventually settled on. But local summers are so hot that eggs were literally boiling inside. The green roofs create a heat differential that aids airflow and reduces the interior temperature.
I was worried we’d be expected to start from scratch, with planks and nails, but Dick had already done the hard work, and we each got with a constructed birdhouse (Longwood sells them in its gift shop for $30 apiece), a pot of soil mixed with coarse gravel, and half a flat of mixed sedums, specially grown at Emory Knoll Farms in nearby Street, Maryland, where fifth-generation farmer Ed Snodgrass focuses on hardy perennial green-roof plants that can stay outdoors year-round. Our class instructor, Joyce Rondinella—a down-to-earth (as befits someone who plays in dirt) earth mother and gardener in Longwood’s conservatory—gave us a crash course in potting media and planting tips, while Dick filled us in on the life cycle of the bluebird, how to clean and tend our houses, and where to site them. Then we got to work, tucking Ed’s beautiful, strong-rooted plugs onto our roofs and packing them in with soil.
Figuring out how to space the plugs, how deep to plant them, and how much dirt to add took some doing, but by the end of an hour and a half, we were all admiring our masterpieces. Dick offered tips on pointing the openings of houses away from the weather, situating them near small bushes so wobbly fledglings can aim for their branches, and what to do if visitors other than bluebirds take up residence. (If it’s wrens or chickadees, be happy; if it’s sparrows, well, I hesitate to pass on Dick’s coldhearted advice. Suffice it to say, he’s no Jack Sparrow.)
When we were finished—and finished congratulating one another on our artistic abilities—Joyce and Dick et al. helped us tote our birdhouses (all that soil makes them heavy!) to our cars. We were then free, if we liked, to explore Longwood’s conservatory and grounds for the rest of the afternoon. I did, and ran into Joyce again an hour or so later, in the Estate Fruit House, where she was doing double duty amongst the sweetest-smelling viburnum I’ve ever encountered.
My husband and kids laughed at the notion of a green-roof birdhouse, but when I brought mine home, they had to admit it was cool. If you’re interested in making your own green-roof birdhouse, you can find plans here. For information on Longwood’s continuing education courses, go here. And for heaven’s sake, if you haven’t been to Longwood lately, go! It’s a national treasure that will stuff you full of gardening ideas for years to come.
Slideshow photography by John Shipman.
