Climate-Conscious Gardening

MGNV - Sustainable Landscaping LogoAs our changing climate brings more unpredictable weather patterns, gardeners play an increasingly important role in serving as stewards of the environment. Learn about five categories of practical actions homeowners can take in their own backyards to either mitigate or adapt to changes in our climate.

This free online class was offered by Extension Master Gardeners.

Speaker: Elaine Mills, Extension Master Gardener
Zoom session, June 5, 2020

Video of Presentation

Additional Resources

Addendum: Additional Details and Answers to Chat Questions

Elaine Mills, presenter of “Climate-Conscious Gardening”

A listener asked for suggestions on guides for identifying grasses. A guide that covers 135 species is Grasses: An Identification Guide by Lauren Brown, 1992. Grasses, Sedges, Rushes: An Identification Guide, an updated and amended version of Brown’s original book, will be available for purchase in mid-August of this year. It includes color photographs as well as the original line drawings.

Another listener asked about sources for push mowers, and a chat box response mentioned Ace Hardware as a local source. See a detailed review of “10 Best Reel Mowers of 2020,” which includes information on cutting height adjustments for each model.

In response to a question on Golden Ragwort (Packera aurea), a desirable native ground cover, I should have clarified that the plant that concerns allergy sufferers is Ragweed in the Ambrosia genus.

In the discussion on control of invasive plants that are extremely difficult to eradicate, we should have used the term herbicide rather than pesticide.

Regarding a question on Black Locust (Robinia pseudoacacia), the original native range of this tree is uncertain, although one population is thought to have centered about the Appalachian Mountains. The Digital Atlas of the Virginia Flora now lists it as native in all counties of Virginia, although it indicates that in the Piedmont and Coastal Plain it has “at least partly naturalized through post-settlement spread.” Black Locust is considered a noxious weed in parts of the U. S. because of its opportunistic rapid growth. While the City of Alexandria describes the plant as “weedy in disturbed areas,” it does not include it on its list of invasive plants because it is “not [a] non-native invasive species, [it does] not degrade natural areas, and [it is] important for native wildlife.” The flowers produce abundant amounts of nectar and pollen which support native bees and attract honey bees as well as hummingbirds. The tree is also a host plant for the caterpillars of many butterflies, including the Silver-spotted Skipper and the Clouded Sulphur.

The book I recommended for information on techniques and timing for pruning and pinching back to control the growth of herbaceous plants is The Well-Tended Perennial Garden: The Essential Guide to Planting and Pruning Techniques by Tracy DiSabato-Aust, 2017.

Regarding wind-resistant plants, needle-leaved conifers are a good choice as are such hardy native trees and shrubs as redbud, persimmon, American holly, and viburnums. Native grasses are extremely wind-tolerant, and they can serve as a miniature windbreak for less wind-resistant plants. Retaining walls, fencing and trellis panels can also serve as effective wind buffers for plants.

Regarding the question on whether invasive plants could enter a garden from bird seed, I would say that somewhat weedy volunteer plants (sunflowers and grains like millet or milo) may sprout from uneaten seed that lands on the ground, but these species are not classified as invasive. Check the list of ingredients for purchased seed to learn what might sprout. Be aware that the discarded hulls of sunflower seeds may attract rats.

Two questions arose from the recommendation to retain fallen leaves for overwintering caterpillars. I wanted to mention that some birds forage for insects in the leaf litter as well.

As far as any problems posed by ticks, it is true that they can live in leaf litter. A recently posted article on our MGNV website recommends that homeowners keep areas where they play and relax clear of leaves and create a mulch barrier. For further details on protection for people and pets in the yard see Protecting Yourself from Ticks… without Harming Pollinators.

Note that invasive Japanese barberry bushes may create prime habitat for ticks as the white-footed mice that serve as carriers for Lyme disease like to nest beneath them.

With respect to diseases in leaf litter, there should be no problem with retaining fallen leaves from healthy plants, principally from trees in woodland areas. You should always clear away and dispose of leaves resulting from foliar diseases, such as leaf spot, leaf blight, rust, and powdery mildew, in the trash. 

I did not have time to discuss the impact of climate change on vegetable gardening during this presentation, but here are some climate-conscious pointers for vegetable gardeners from Dr. Sara Via, Climate Extension Specialist at the University of Maryland:

  • Weeds:  Weeds benefit from warmer winter weather. Weed early (when plants are little) and often. Mulch sustainably and use newspaper or straw on paths. Use no-tilling methods; weed seeds can stay in soil seed bank for 20 years. Stirrup hoe highly recommended for covering an area quickly and garden bandit for easy precision weeding.
  • Pest control: Provide nectar, pollen, and protection for natural pest enemies. Be vigilant and learn signs of damage. Use row covers immediately, if necessary. Decide on control strategies before pests arrive.
  • Heat stress: Temperatures over 86° F reduce pollination and fruit set. Use existing shade or build shade using 30% shade cloth with open ends. Try heat-tolerant varieties.
  • Flooding: Avoid soil compaction by not walking on wet soil. Delay planting and stagger planting times. Improve drainage and soil health. Slow down water with bioswales. Monitor water flow which can bring pollutants from neighbors. Don’t eat greens exposed to flood water because of concern about bacteria.
  • Drought: Choose drought-tolerant plants. Mulch around plants. Use drip irrigation. Choose native plants with deep roots.
  • Building soil: Make compost to reduce food waste and use it to help soil both hold and drain water as well as to feed soil microbes. Plant cover crops to add organic material and nitrogen.