By Drew Chaney, Piedmont Discovery Center
Every day, I see people asking in person and online, “What natives should I plant in my yard?”
Oftentimes, the answers given are very generic and do not serve biodiversity. We have lived our entire lives under the paradigm of Euro-colonial horticulture, where the value of a plant in the landscape is dependent upon its “performance”, by which we mean how well an individual species can grow under certain conditions in the domestic landscape, and how closely it adheres to the aesthetics of the formal style of American landscaping popularized as a way of imitating the British aristocrats of yesteryear (who collected plants from around the British empire and were able to maintain unnaturally perfect lawns and gardens through armies of servants). This individualistic method, focusing on selecting an assortment of individual species based solely on novelty and/or appearance, results in what are known as novel ecosystems, which contain mixtures of species from around the world with little or no shared evolutionary history, and which would not exist without modern human behavior.
The contemporary American residential landscape, with its lawns of Eurasian tall fescue (Lolium arundinaceum) or Kentucky bluegrass (Poa pratensis) and heavily mulched beds with scattered “foundation plantings” is a classic example of a novel ecosystem. Here in Virginia, this type of landscaping often consists of evergreen shrubs such as boxwood (Buxus sempervirens), privet (Ligustrum spp.), Chinese holly (Ilex cornuta), abelia (Abelia spp. ), and heavenly bamboo (Nandina domestica), along with deciduous cultivars of Japanese barberry (Berberis thunbergii) or burning bush (Euonymus alatus) for “visual appeal”. Other “accent” plants used include Chinese silvergrass (Miscanthus sinensis) and ravenna-grass (Tripidium ravennae). Trees such as Japanese cherries (Prunus serrulata, P. subhirtella), Callery pear (Pyrus calleryana), crepe myrtle (Lagerstroemia indica), and southern magnolia (Magnolia grandiflora) are often used as ornamental flowering trees.
A suburban backyard, with expansive mowed lawn, hardscaping, and mulched beds with widely spaced exotic shrubs.
You may already know that lawns and exotic species aren’t beneficial. You are probably aware that many of the species mentioned above are invasive and highly damaging to local ecology. After all, that’s why you want to plant natives instead. But what happens when we are unable to break free of the colonial, individualistic mindset when approaching native plants, and fail to understand the ecological meaning of the term native? We just keep creating new novel ecosystems. Most “native gardens” are just another example of a modern human-created mishmash of species which may never occur together in a natural ecosystem, much less in your local area and in conditions similar to those on your site. Furthermore, they often contain cultivars, which are selected from or bred for anomalous characteristics such as dwarfism, different flower color, reproductive parts replaced by sterile petals (they are double-flowered), or other features which make them less recognizable to insects which feed on or pollinate them. And since almost all of these “nativars” do not come true from seed, but rather are propagated vegetatively, this leads to a stunning lack of genetic diversity. The vast majority of plants in a wild population don’t represent an evolutionarily disadvantageous genetic mutation.Cultivars often do With all of that in mind, is it possible then to garden in a way that truly supports biodiversity?
The answer is yes, and it requires a shift from the aforementioned focus on plants to one on systems. Plants are one part of an ecosystem, as are birds, mammals, reptiles, insects, fungi, soil, etc. Native plants are ones which have a long evolutionary history in a given ecosystem, allowing for them to develop complex relationships with other organisms occurring with them. It has nothing to do with political boundaries, and everything to do with ecological context. A species which evolved in a completely different ecosystem a few miles away and that does not naturally occur in it, is not native to it. Biodiversity is wholly dependent on the existence of healthy, functioning ecosystems, not individual plant species isolated from their natural context. If you cut your hand off, would it still be able to accomplish any tasks on its own? Obviously not. Likewise, a milkweed plant in a novel ecosystem won’t sustain a healthy population of monarch butterflies on its own. The butterfly needs not only the milkweed that serves as its larval host, but the rest of the grassland too. Attracting a pollinator is not the same thing as helping a pollinator. If you want to help bees, butterflies, and other wildlife, you’ll need to give them what they need,not just things that “attract” them, but rich and sustainable groupings of plants that allow them to survive, reproduce, and sustain through time. Observations in natural habitats in the Piedmont region prove that what they need is a great number of plant species, growing closely and overlapping, and in great abundance. Natural diversity can be accomplished in even a small yard or an island in a parking lot. Resist the urge to plant simple rows of “native” flowers, and do what you can to increase diversity and density in a way that mimics the natural evolutionary context for pollinators; remembering that the needs of native animals may not always align with your aesthetic preferences.
The only way to understand what ecosystems are truly suited to your home landscape is to study existing locally native examples. This sounds intimidating, but it’s not really as difficult as it might seem. It does take time, and a willingness to observe and learn. Spend time observing your soil type, drainage, and moisture conditions. Look into your underlying geology. Think about your chosen site’s light, aspect, elevation, and slope. Then seek out natural plant communities in your local area (~ 20 mile radius) which occur in similar conditions. These ecosystems are what is referred to as the natural trajectory of your land (what would occur there if it wasn’t for modern-day human disturbances). When you have established some familiarity with these ecosystems, then you can begin constructing a restoration plan by modeling species lists, density, etc., after real, local examples.
Examples of remnant mafic savanna vegetation in the central Virginia Piedmont served as reference sites for a restoration in the same backyard shown above.
It may be harder to learn what ecosystems belong on your landscape than it is to go to a nursery or garden center and plunk down the money for some random ornamentals (even “native” ones), but the ecological value is well worth the extra effort.
While native ecosystems may present a different aesthetic than traditional European-style horticulture, that doesn’t mean they can’t also fit into a more formal setting.
Native grasslands made up roughly 50% of the Virginia Piedmont prior to European colonization. They currently occupy less than 1%. The grassland ecosystems of the Southeast are some of the most biodiverse in the nation .Piedmont grasslands may contain as many as 123 native species in 100 square meters! Your own yard may not be much, but imagine if your neighbors followed your lead. Then your street. Your community. It’s long past time to imagine a new way of looking at our home landscapes, one that asks not “What can these plants do for me”, but “What can I do for my local ecology?”
Read more about the concepts that guide our approach to ecological restoration: https://centerforurbanhabitats.com/ecosystem-modelling-in-landscape-design/
Flora of Virginia – Complete guide to Virginia’s flora https://floraofvirginia.org/
Natural Communities of Virginia – invaluable resource for learning about Virginia’s ecosystems https://www.dcr.virginia.gov/natural-heritage/natural-communities/
Forgotten Grasslands of the South: Natural History and Conservation by Reed F. Noss