Heat Damaged Leaves

 

Extreme heat and the angle of the sun have damaged leaves on this Rhaphiolepis hedge.

This story has been updated to include comments from Carol Bornstein, Director of the Nature Garden at the LA County Natural History Museum.

The extreme heat has also taken a toll on neighborhood plants. You may have noticed large burn spots on trees and plants that actually closely resembles frost damage. Experts say the damage is caused by a combination of the angle of the sun, the extreme heat and warm air moving strong sunlight through the garden burning the leaves. In some cases, you can actually see the pattern occurs in a pattern across the garden.

“It’s amazing to see thick-leafed plants like Rhaphiolepis suffer this kind of damage mostly likely caused by the intense temperatures and excessively low humidity after a relatively humid spring,” said Carol Bornstein, Director of the Nature Garden at the LA County Natural History Museum.

Bornstein advised preparing in advance of a heat wave by deep watering plants that you think might be susceptible to damage or are newly planted.

“If you can irrigate before, it’s like money in the bank, that plants can draw from in these extreme conditions,” said Bornstein. But if you can’t and your plants are damaged, Bornstein said most the plants will recover.

As unappealing as the brown leaves are, it’s best to leave them as they are protecting the leaves underneath. Also, any pruning would stimulate new growth and the heat of summer is not a good time for new growth in plants. The plants should survive assuming there aren’t other issues affecting them and if they are getting enough water.

“You should always check to make sure plants are getting sufficient water,” recommended Judy Horton, garden designer, “the best way to do that is with a soil probe.”

Horton says there are some plants in the garden that don’t need much water and using a probe is the only way to check to see if plants are getting too little or too much water. If you need to add extra water, she recommends hand watering in the early morning hours to get plants through this extreme heat. It’s best to avoid watering in the evening which can promote the growth of mold and fungus that can be harmful to plants. Bornstein said night watering can awaken pathogenic fungi in the soil that like heat and moisture.

Keep an eye on trees, too. Intense heat and dramatic drops in humidity can cause trees to suddenly drop leaves and in some cases limbs. Deep watering trees, if it’s not raining when it normally should rain,  will help strengthen trees, avoid stress and keep them healthy through hot weather.

The leaves on this Boxwood maze have been damaged by the extreme heat over the past few days. But there’s still a lot of green on the hedges so they should recover.

 

About Patricia Lombard

Patricia Lombard is the co-editor and publisher of the Larchmont Buzz. Patty lives with her family in Fremont Place. She has been active in neighborhood issues since moving here in 1989. Her pictorial history, "Larchmont" for Arcadia Press is available at Chevalier's Books.

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