What You Can Plant to Help
By Kimberly Marsho, Extension Master Gardener
Bringing up Baby
It’s spring! And as you may have noticed from all of the early morning chatter outside your windows, bird parents in Alexandria and Arlington have been hard at work. From dawn to dusk they are busy collecting caterpillars to feed their hungry baby chicks.
As opposed to the seeds many of us see adult birds munch on at our feeders, caterpillars are the key food required for raising healthy chicks. According to University of Delaware entomology professor Douglas Tallamy, one pair of Carolina chickadees needs to bring 350 to 570 caterpillars PER DAY to feed their clutch of three to four chicks. Every three minutes for 14 hours a day for 16–18 days, from hatching to fledging, both parents take turns bringing food to the nest. Baby birds need the soft, protein rich nutrition that caterpillars provide.  We all know that parenthood is lots of work but….wow!
Parents often feed their chicks even after they fledge, similar to what some human parents experience these days with their Millennial fledges. And while local parents have recently been confronting scarce supplies of paper products and frozen pizzas, these poor bird parents will tell you they’ve been suffering caterpillar shortages in this urban area for years.
Want to help these poor parents out?
Maybe the best contribution you can make to nature here in Northern Virginia is to grow your own bird food by planting a tree that supports caterpillars. In addition to providing habitat for caterpillars, you will beautify your home. With a larger tree, you will enjoy shade and a cooler home for years to come in the sweltering summer months of our hot and humid region. Properly placed, trees can significantly lower your cooling bills while boosting the value of your home. And those caterpillars that do survive your ravenous chicks? They will become the lovely summer and fall butterflies and moths that grace our home landscapes.
What tree should we get? Where should we plant it?
First, decide whether you want and have space for a larger shade tree, or whether you are looking for something smaller. So many tree options mean you can find the tree that fits your budget, your landscape, your taste, and grow lots of bird food,
Place deciduous shade trees on the southwest side of the house to block late afternoon sun in the summer and cool your house. The leaves will drop in the fall, allowing the sun’s rays to warm your house in winter. Place evergreens on the north side of your house to block cold winds in the winter months.
Survey your yard and surrounding space: where will you plant your tree? If you have space, go for a large shade tree (or two or more). In our area, the best location for shade trees is on the southwest or southeast sides of your home. A tree in these locations that drops its leaves in the fall will ensure you DO get the sun’s rays in the cold months when you want them. Also consider the mature size of the tree so you can place it far enough away from your house and from power lines. For example, if you are planting an oak with a mature spread of 50+ feet, you want to plant it about half that distance from your home. A single Quercus Alba (white oak) can support more than 500 species of caterpillar; an elm more than 200.
Here are some good trees for caterpillars that are exceptionally carefree and beautiful and will thrive in our area:
|Caterpillar species supported|
|Large Shade Trees|
|White oak (Quercus alba)||534|
|Black gum (Nyssa sylvatica)||26|
|Red maple and sugar maple (Acer rubrum and Acer saccharum)||287|
|American elm (Ulmus americana): blight resistant varieties like ‘Princeton’ or ‘Valley Forge’||213|
|American linden, also known as American basswood (Tilia americana)||150|
|Medium Shade Trees|
|American hop-hornbeam or ironwood (Ostrya virginiana)||94|
|Serviceberry (Amelanchier spp., such as laevis, canandensis, arborea, choose from many cultivars with size and form suited to your site)||124|
|Hawthorn ‘Winter King’ (Crataegus viridis ‘Winter King’)||168|
|American dogwood (Cornus florida)||118|
|Small Trees (OK for large containers and under power lines)|
|Apple serviceberry (Amelanchier x grandiflora, ‘Autumn Brilliance’ or choose from many cultivars with smaller size and form)||124|
|Eastern redbud (Cercis canadensis)||19|
|Fringetree (Chionanthus virginicus)||8|
|Sweetbay magnolia (Magnolia virginiana)||21|
Need more help?
- Master Gardeners of Northern Virginia provide extensive information online about these trees and other good choices in the Tried and True Native Plant Selections for the Mid-Atlantic resources on the website. They also staff plant clinics at the local farmers markets and a help desk at the Fairlington Community Center.
- A great brochure for how to plant and care for your new tree is Planting Trees, VCE Publication 426-702.
- In Alexandria, you can find information on trees, including street trees on the Urban Forestry Management page of City of Alexandria website. Alexandria usually holds two native tree sales per year with trees available at a reduced price.
- In Arlington, for help with tree planting including FREE trees, visit Tree Planting Programs.
- Small Trees Make Big Canopies is a new VCE Extension Master Gardener program, initiated in the spring of 2020 by interns Alicia Martini and Pam Quanrud, to help expand the tree canopy in Arlington. “Free Trees” seeks to give away hundreds of small (in size, as in saplings) native trees to help restore the region’s tree canopy.
- For energy efficient landscaping and tree shade information, visit Landscaping for Shade from energy.gov.
Native Plant Finder, from the National Wildlife Federation, is a website that will help you find the best native plants specifically for your area that attract butterflies and moths and the birds that feed on their caterpillars, based on the scientific research of Dr. Douglas Tallamy.
 Douglas W. Tallamy, “The Chickadee’s Guide to Gardening,” New York Times, March 11, 2015, https://www.nytimes.com/2015/03/11/opinion/in-your-garden-choose-plants-that-help-the-environment.html?ref=opinion&smid=tw-nytopinion&_r=1