Why are some spring plants blooming now?

COLUMBIA, Mo. — University of Missouri Extension horticulturists are fielding questions about plants that are blooming and leafing out of season.

MU Extension horticulturist Debi Kelly, who serves as the state extension Master Gardener coordinator, says she’s noticed many social media postings about spring-blooming flowers and shrubs, especially irises and lilacs, budding and blooming in fall.

“Flowers and trees are reacting to Missouri’s unusual weather this year,” said Kelly in a press release. She attributes the unseasonable blooming to stress from back-to-back growing seasons of hot and dry weather. Recent fluctuations in temperatures and shortened daylight hours add to the stress.

Spring-blooming plants set their flower buds for the next year in early summer after spring blooms fade, she says. Stress from conditions like drought force plants and trees into a dormant-like state. Then, when temperatures fluctuate between warming and freezing, like they have this year, it confuses the plant’s perception of what season it is.

There is little need for action now except to continue to water plants well so that water soaks into the ground, says Kelly. Generally, healthy plants are likely to survive, although they may produce fewer blooms than usual next spring, she says.

Continue to water perennials and trees this fall until soil temperatures drop to 40 F. “It is important to put water back into the ground,” Kelly says.

Plants show signs of stress before trees do. Usually, it takes about two years for trees to show signs of drought if they weren’t watered regularly, so that is why trees are just now showing issues. Kelly says fruit trees may bloom in the fall also if they are stressed.

Stressed plants and trees may be more susceptible to disease next year, so gardeners should watch for signs of foliar disease and pest damage, she says.

Fall is a good time to test soil to make sure that you are providing proper nourishment to your plants next growing season. To learn how to take a soil test, go to https://SoilPlantLab.missouri.edu.