Ozone can be stressing your garden

These pictures compare a normal tulip tree leaf
 and one exposed to too much ozone. 

(Photos courtesy National Park Service)

Hot, smoky conditions create dangerous pollutant levels

By Debbie Arrington

Smoky skies and record heat make gardening -- or just about any outdoor activity -- intolerable right now. Usually our gardens cope better with these conditions than we do; they can filter out the pollutants and conserve their resources.

But the air is so bad now, even plants are feeling ill effects.

Today (Monday) will be the 22nd consecutive Spare the Air Day for the Bay Area -- and the greater Sacramento region, a record for this current streak of poor air quality. Driving, operating gas-powered equipment, barbecuing and other activities are discouraged (if not prohibited).

The past few days that bad air has been accompanied by excessive heat, creating a ground-hugging layer of ozone. That's making our eyes water -- and our plants suffer.

Ozone is created by a combination of wildfire ash and other pollutants (usually nitrogen oxides and volatile organic compounds), intensified by bright sunlight and triple-digit heat. It can prevent a plant's leaves from properly doing their job. Ozone enters the leaves' stomata and burns the leaves' tissue.

Signs of ozone damage include dark stippling and bleaching of foliage. Plants lose their vigor and stop blooming or yielding fruit. Ozone damage weakens the plant and makes it much more susceptible to pests and disease.

Worried about the long-term effects of too much ozone, researchers and the National Park Service surveyed plants in national parks across the country and found hundreds of species with ozone sensitivity, from ash and asters to sycamores and yarrow. Maple, cherry, poplar and plum trees are all on the ozone-sensitive list. Find it here: https://irma.nps.gov/NPSpecies/Reports/Systemwide/List%20of%20Ozone-sensitive%20Species

What can you do to help your plants cope? Keep them hydrated. Offer them some afternoon shade. Wash ash and soot from leaves.

And continue to "Spare the Air." These smoky conditions are expected to last at least through Wednesday.