“I love mulch. That would be obvious to anyone who has ever talked gardening with me. Big piles, small piles, inches of mulch scattered everywhere. Love it! …
“But a long-held recommendation from the University of California flies in the face of the ‘all mulch, all the time’ rule regarding protecting citrus from the effects of freezing temperatures: ‘A cover crop or mulch can lower minimum temperature at night, posing an increased threat from freeze damage.’
“So, our advice has been over the years: Rake away mulch from beneath citrus before an expected frost or freeze.
“Now, the California Landscape Contractors Association is offering the opposite advice in a release regarding frost protection: ‘Mulching with a partially composted material is one the best ways to protect plant roots because it helps insulate the soil, reducing heat loss and minimizing temperature fluctuations.’”