July is the month we celebrate our country’s freedoms, often in our outdoor living spaces. It is also the summer month when our gardens are reaching peak beauty ‒ or maybe not.
It is a good month to assess what is working well and what isn’t. And it may be the perfect time to declare freedom from invasive and exotic plants and redirect the gardens to more native plants.
A gardening movement, the American native-plant movement, is changing the way we plant landscapes. It started in the 1960s with Lady Bird Johnson, who advocated for beautifying America’s highways by using native plants and flowers. Her affinity for planting native species made it easier for landscape designers to begin using them in smaller garden designs.
Now, in an era of climate change, the use of native plants becomes even more important.
The world’s monarch butterflies have declined 90%, and three billion birds are gone. What’s more, according to a report by the Center for Biological Diversity, the American honeybee has declined by 89% in relative abundance and continues to slide toward extinction.
Native plants produce habitat for birds, bees and insects essential to keeping our world green and growing. The National Wildlife Federation (NWF) began its Gardening for Wildlife program nearly 50 years ago and is today a national voice for creating landscapes and gardens using native plants (https://www.nwf.org/Home/Garden-for-Wildlife). NWF partners with regional garden organizations as well as leading research scientists.
According to Mary Phillips, the head of the program, research shows that one in four people purchased native plants in 2019 but that the number rose in 2021 to one in three. “It is a very encouraging sign,” she says. The program aims to show that gardens big and small can make a difference in nurturing local bees, butterflies and birds.
Out With the Invasives
Redesigning a small Hill garden to be a native habitat has wonderful benefits. Residents often adopt the yard plantings left by the previous owner, but too often those gardens harbor invasive species that crowd out native and cultivated plants. Take a walk down your block and you will see invasive English ivy growing everywhere, including up trees.
Another Hill favorite now officially identified as invasive is Liriope, more commonly known as monkeygrass or lilyturf. It grows well in conditions from shade to full sun and needs little maintenance. The problem is that it aggressively extends runners and spreads quickly in gardens.
There has also been a trend to plant ornamental grasses, and some, like giant reed grass, can spread just like bamboo. Others can send underground runners that spread 20 feet from the original plant, adding two to three feet a day.
Once invasives make the garden their home, there is no room or water for other plants. Invasive plants cause an estimated $100 billion in damage each year in the US.
The National Park Service lists 40 species of invasives for the Washington, DC, area in its Invasive Plant Atlas (https://www.invasiveplantatlas.org/). The DC Department of Environment & Energy also provides information on these plants.
Choosing the Right Native Plants
Phillips suggests doing a little research before converting to native plants and creating wildlife habitats. “The great thing is, there is so much information and advice about the benefits of a native plant,” she says. “It is pretty easy to find out what plants will bring bees, birds and insects to your garden.” Phillips says that just planting natives in a pot on a balcony can help bring balance to the environment. She also suggests starting small and expanding the native plants as you tend the garden.
NWF has also launched an easy way to get started by providing native plant collections available online. It delivers the plants to your door at the appropriate time to plant. NWF claims that one collection can double a garden’s wildlife in a single season. The farms NWF partners with are certified free of chemicals, including neonicotinoids, which are deadly to butterflies, bees and birds. The native plants grow under very stringent inspections and follow state audit requirements.
NWF provides Garden for Wildlife plants to 36 states and Washington, DC. The program is in its first year, says Phillips, and will expand in the coming years. “One problem we have seen is that some nurseries offer native plants, but they often have been treated with chemicals, and then lose many of their wildlife benefits,” she says. “With our program you know you are getting an excellent species of plant that is going to help the local wildlife.”
Ratio of Plants to Wildlife
Behind each plant stands a team of scientists who have assembled the right combinations of plants for a local garden. One of the leading research scientists is Doug Tallamy at the University of Delaware Entomology Center. He has published a list of his top-10 species for insect biodiversity, measured by the number of moths and butterflies supported by each plant. Number one is the oak tree (and Capitol Hill has many). One oak tree can support over 500 species. A willow tree supports 450 species. A single pine tree supports over 200 species. For every plant, scientists can estimate the number of insects, bees, butterflies and moths, birds and other wildlife that require that plant’s flowers, blooms or plant to flourish.
“In the past,” says Tallamy, “we have asked one thing of our gardens: that they be pretty. Now they have to support life, sequester carbon, feed pollinators and manage water.”
As you look at your garden this July, can you identify places to plant a native collection, a shrub or tree? Are you ready to do your part on climate change and action? Can we free our gardens from the pesty past and dig up the invasive culprits?
Yes, we can! Reach out to the National Wildlife Federation’s Garden for Wildlife website for all kinds of tips and information. New native plant collections will soon be added, ready to ship for your fall plantings. With just a little effort, Capitol Hill gardeners can do their part to save our planet.
Rindy O’Brien is committed to helping green Capitol Hill. Contact her at firstname.lastname@example.org.