Wildfire smoke doesn't just affect people - it can also negatively affect the health of plants and trees.
While most established plants can tolerate short periods of smoke, prolonged exposure combined with heat and drought can reduce growth, interfere with photosynthesis, and place additional stress on landscapes.
Reduced Photosynthesis
Smoke blocks and scatters sunlight, reducing the amount of light available for photosynthesis. With less energy from the sun, plants may grow more slowly and produce fewer flowers, fruits, or vegetables. Fortunately, most healthy plants recover once clear skies return.
Clogged Leaf Surfaces
Ash and fine particles can settle on leaves, partially blocking the tiny pores called stomata. These pores allow plants to exchange gases and regulate water loss. A heavy coating of ash may temporarily reduce this process, although light rain or irrigation often washes the particles away.
Heat and Drought Stress
Wildfire smoke is frequently accompanied by hot, dry weather. Trees and plants may already be struggling with limited soil moisture, making them more susceptible to pests, diseases, and leaf scorch. Newly planted trees and shallow-rooted vegetables are especially vulnerable.
Effects on Trees
Mature trees can usually withstand several days or even weeks of smoky conditions, but prolonged drought combined with smoke may slow growth and weaken their natural defenses. Stressed trees are often more attractive to bark beetles and other insect pests.
Garden Vegetables
Most vegetables continue growing during smoky periods, but reduced sunlight can slow ripening. Tomatoes, peppers, squash, and other sun-loving crops may take longer to mature if dense smoke persists for several days.
Pollinators
Smoke may reduce the activity of bees, butterflies, and hummingbirds, resulting in less pollination for flowering plants and some fruiting crops until air quality improves.
How to Help Your Garden
Colorado Considerations
Colorado gardeners often experience smoky periods during summer. In most cases, smoke alone causes only temporary effects, but when combined with prolonged drought and high temperatures, it can significantly increase plant stress. Keeping soil evenly moist and minimizing additional stress gives plants the best chance to recover.
Keep in mind that wildfire smoke rarely kills healthy plants by itself, but it can slow growth, reduce photosynthesis, and compound the effects of heat and drought. With proper watering and good plant care, most trees, shrubs, flowers, and vegetables recover well once skies clear and normal growing conditions return.
Trees don't like wildfire smoke either - here's their interesting mechanism for handling it.
Reduced Photosynthesis
Smoke blocks and scatters sunlight, reducing the amount of light available for photosynthesis. With less energy from the sun, plants may grow more slowly and produce fewer flowers, fruits, or vegetables. Fortunately, most healthy plants recover once clear skies return.
Clogged Leaf Surfaces
Ash and fine particles can settle on leaves, partially blocking the tiny pores called stomata. These pores allow plants to exchange gases and regulate water loss. A heavy coating of ash may temporarily reduce this process, although light rain or irrigation often washes the particles away.
Heat and Drought Stress
Wildfire smoke is frequently accompanied by hot, dry weather. Trees and plants may already be struggling with limited soil moisture, making them more susceptible to pests, diseases, and leaf scorch. Newly planted trees and shallow-rooted vegetables are especially vulnerable.
Effects on Trees
Mature trees can usually withstand several days or even weeks of smoky conditions, but prolonged drought combined with smoke may slow growth and weaken their natural defenses. Stressed trees are often more attractive to bark beetles and other insect pests.
Garden Vegetables
Most vegetables continue growing during smoky periods, but reduced sunlight can slow ripening. Tomatoes, peppers, squash, and other sun-loving crops may take longer to mature if dense smoke persists for several days.
Pollinators
Smoke may reduce the activity of bees, butterflies, and hummingbirds, resulting in less pollination for flowering plants and some fruiting crops until air quality improves.
How to Help Your Garden
- Water deeply and consistently, especially trees and shrubs.
- Maintain a 2–3 inch layer of mulch to keep roots cool and conserve moisture.
- Gently rinse heavy ash from leaves if it accumulates, but avoid excessive spraying during the hottest part of the day.
- Delay fertilizing or heavy pruning until plants have recovered from the stress.
- Continue harvesting ripe fruits and vegetables to encourage ongoing production.
Colorado Considerations
Colorado gardeners often experience smoky periods during summer. In most cases, smoke alone causes only temporary effects, but when combined with prolonged drought and high temperatures, it can significantly increase plant stress. Keeping soil evenly moist and minimizing additional stress gives plants the best chance to recover.
Keep in mind that wildfire smoke rarely kills healthy plants by itself, but it can slow growth, reduce photosynthesis, and compound the effects of heat and drought. With proper watering and good plant care, most trees, shrubs, flowers, and vegetables recover well once skies clear and normal growing conditions return.
Trees don't like wildfire smoke either - here's their interesting mechanism for handling it.