The Climate Responsiveness Project: Keystone Plants

February 2, 2026

In August 2025, the RCMG Climate Responsiveness Project released a guide describing climate responsiveness actions. Now, they’re sharing a series of newsletter articles to help volunteers explore some of the practical steps featured in the guide.

Each new gardening year, as we page through plant catalogs and gardening magazines, our eyes are drawn to the many new, almost irresistible vegetable, flower, shrub, and tree varieties. Maybe there is a must-have new hydrangea or hosta. The sun and water requirements, size, and hardiness zone are appropriate for your garden. Seems like the right plant for the location you have in mind. But, before purchasing that plant, step back and ask “is this a climate-conscious plant choice?" 

Selecting a “keystone” plant species is one of the characteristics of a climate-conscious plant choice. A keystone is a central stone at the top of an arch that holds the two sides together. In the natural world, the arch consists of the relationships between the native plants and insects which coevolved over time. 

In a recent University of Minnesota Extension 2026 Pollinator Series webinar, Heather Holm, author and founder of the digital Minnesota Native Bees field guide, defined keystone plants as those which support the most insect species. Caterpillars feed on trees and are an important food source for birds. Not all trees are equal, however, and among all the tree genera across the U.S., only 14% support 90% of the Lepidoptera caterpillar species.  The keystone trees are oaks, willows, cherry/plum, pine, poplar/aspen, and maple. Oak alone supports 940 species of caterpillars! 

Our native bees are also dependent on native plant species for food. Heather Holm noted that about a third of our 500+ native bees in Minnesota are specialists, relying on the pollen of specific native plant genera with which they coevolved. The top keystone plants for specialist bees in the Central U.S. include Helianthus (sunflower), Solidago (goldenrod), Symphyotrichum (aster), Rudbeckia (black-eyed Susan), Erigeron (fleabane), and Cirsium (thistle).

Where does this leave the hydrangea or hosta that beckons and calls out “Buy me!” It’s okay. We all need a little “plant candy.” At the same time, think about the caterpillars, birds, and bees. Is there an oak tree in your yard or somewhere nearby? Maybe you lost ash trees; replace them with keystone trees. To benefit the bees, begin a new native garden or add drifts of native goldenrod, sunflower, and asters to an existing sunny perennial garden or wild geranium, false Solomon’s seal, and Jacob’s ladder to a shade garden. 

The National Wildlife Foundation is a comprehensive resource for identifying keystone plants by ecoregion and incorporating them into the landscape. The website is  https://www.nwf.org/keystoneplants.