How to celebrate Earth Day with eco-conscious gardening
Q: I want to be more mindful about how my landscaping choices impact the environment so I can reduce negative consequences. Do you have suggestions for low-impact and eco-conscious gardening practices?
A: Certainly, and with Earth Day coming up on April 22, now’s a great time to focus on the impact of our landscapes. Fortunately, there’s many ways we can adjust our gardening practices to minimize our carbon footprint and protect local habitats.
Keep the soil covered with plants or mulch. Not only does this reduce erosion (which moves nutrients and pollutants to our waterways), but it also supports soil health. Living plant roots support beneficial microbes, which in turn aid in plant growth and convey protection from some diseases. Bare soil is also a great nursery for weedy and invasive species.
Expect some pests and diseases, and tolerate minor plant damage. Focus instead on issues that can cause more serious damage, and intervene early to prevent an outbreak by monitoring plants regularly. If you need to resort to pesticides, select organic or low-risk products, and be mindful of pollinator exposure. You don’t need to eliminate a pest (and you likely can’t long-term), just suppress its population enough for the plant to recover.
Test your soil before fertilizing. Applying unnecessary elements is wasteful, polluting and risks harming soil life. Mature landscape plants rarely need supplemental nutrients. The two main exceptions are lawns and crops (vegetables and fruits), since we demand a lot of each in terms of productivity. Soil tests will show you which exact nutrients are low enough where fertilization will benefit the plants.
Compost plant debris, old potting mix and food scraps. By keeping soil and debris on-site, you reduce transportation energy use and the chances of introducing invasive pests (like jumping worm or stiltgrass seeds) to new areas. Organic matter improves soil health and returns nutrients to the soil to further reduce the need for fertilizer.
Convert unneeded lawn to other plantings, ideally with primarily locally-native species. No other groundcover tolerates the level of foot traffic or pet use that turf does, but for less intense uses you could create a pathway through a planting bed if you need to routinely access certain areas.
Remove invasive species, which you inherited with a new house or planted before you realized they were a menace to natural areas. Replace them with locally native species when possible so you increase benefits to pollinators and other wildlife.
When you can, use a diverse array of plants to support beneficial insects. Think of it as a tempting buffet for pollinators and the natural enemies of insect pests.
Conserve water and reduce runoff by irrigating only when plants need it and target watering to those most sensitive to drought. Feel the soil several inches below the surface and only water once it’s becoming dry to the touch at that depth. Wet leaves can promote infection so try to only wet the soil when irrigating or water early enough in the day so leaves dry by nightfall. Lastly, use an organic mulch (wood chips, bark, pine needles, or live groundcovers) to slow evaporation so more of that moisture stays in the soil.
Q: I’d love to feed the caterpillars of the butterflies that visit my flowers. I learned that most use different plants than they visit for nectar. Do you have suggestions for native host plants? A:
Each species of butterfly uses one or more fairly specific host
plants, though a few can accept a wide array of unrelated host species. If there’s a particular butterfly species you’d like to attract, you can learn what their preferred hosts are.
Many host plants of butterflies in our area are trees and take up a lot of garden space, but if you have the room, black cherry, willow, hackberry, American elm, pawpaw, Eastern redcedar and sassafras are great options. As is often the case with our native trees, these species also provide resources for plenty of other insects, songbirds and other wildlife, so you get plenty of bang for your buck (and yard space).
There are several native perennial and shrub host plants that you can fit in smaller garden spaces. Most prefer full sun, but some will thrive in dappled shade. Perennials include milkweeds, asters, senna, golden alexanders, violets, toothworts, turtlehead, hairy beardtongue, hibiscus, and pussytoes. Shrubs include spicebush, blueberry, viburnum, New Jersey tea, meadowsweet
spirea and dogwood (redosier, silky, gray, and pagoda). These cover most of the commonly-seen butterflies and the plant species that are easier to source.
False nettle, a fairly nondescript native perennial that grows along damp woodland edges, is worth keeping if growing wild on your property; it feeds the caterpillars of three butterfly species. (Finding some to buy can be challenging, though.) Among vines, pipevine and maypops (purple passionflower) are hosts, but also sometimes hard to source.
Butterflies can often use non-native relatives of their native host plants, but it’s preferable to plant the natives when possible, in case they spread from seed and so they can provide resources for bees and other animals.