Climate change threatens spring wildflowers by speeding up the time when trees leaf out above them

Native wildflowers, such as these Dutchman’s breeches (_Dicentra cucullaria_) that bloom early in spring are losing access to sunlight as trees leaf out earlier. Katja Schulz/Flickr, CC BY

For short-lived spring wildflowers such as wood anemone (Anemone quinquefolia) and Dutchman’s breeches (Dicentra cucullaria), timing is everything. These fleeting plants, known as ephemerals, grow in temperate forests around the world, leafing out and flowering early in spring before the trees towering above them leaf out. Emerge too early, and it will still be winter; emerge too late, and it will be too shady under the forest canopy for essential photosynthesis to happen.

Over their evolutionary history, these plants have figured out the best timing for their survival. But climate change is altering spring growing conditions, and plant life is changing along with it.