Summer Dormancy and the Polypody

Some of our newly planted ferns turned brown last summer. They were pretty, and we didn’t know what we had done wrong.

We eventually learned that the fern, polypodium Californicum ‘Sarah Lyman’, or California polypody fern, is summer dormant. Wikipedia says “In plant physiology, dormancy is a period of arrested plant growth. It is a survival strategy exhibited by many plant species, which enables them to survive in climates where part of the year is unsuitable for growth, such as winter or dry seasons.” California has a Mediterranean climate with warm summers and very little rain for 6 months, a harsh climate for plants. The polypody adapted to our dry summers by going dormant.

This year we documented the polypody’s summer dormancy.

On May 30 the polypody is looking good. The fronds are 1′ tall, growing in the shade of a coast live oak tree, quercus agrifolia.

Polypodium californicum ‘Sarah Lyman’, May 30
Polypodium californicum ‘Sarah Lyman’, May 30

A month later, the polypody is fading fast.

Polypodium californicum 'Sarah Lyman', July 1
Polypodium californicum ‘Sarah Lyman’, July 1

Two weeks later, the polypody is brown. We subsequently cut up the fronds and left them as mulch.

Polypodium californicum 'Sarah Lyman', July 14
Polypodium californicum ‘Sarah Lyman’, July 14

But in late August, fronds begin to emerge from the leaf litter.

Polypodium californicum 'Sarah Lyman', Aug. 26
Polypodium californicum ‘Sarah Lyman’, Aug. 26

And shoots continue to emerge two weeks later.

polypody shoots, Sept. 5
polypody shoots, Sept. 5

California has a tough climate for plants, with little rainfall during the warm summers, when plants need moisture the most. Some California native plants like the polypody have adapted by going dormant during the summer.


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I enjoy travel, art, food, photography, nature, California native plants, history, and yoga. I am a retired software engineer. The gravatar is a Nuttall's woodpecker that visited our backyard.

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