Happy New Year from the UC Master Gardeners of Monterey and Santa Cruz Counties!
Although it's winter we haven't seen much rain so far this year. Let's talk about the culprit, shall we? Are you familiar with La Niña? She's the “little girl” to El Niño's “little boy,” part of the El Niño-Southern Oscillation (ENSO) climate pattern, a periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean. Cooling in the eastern Pacific causes the jet stream to be pushed north, which affects rainfall in the southwestern US. What that means for us is above average rain and below average temperatures in the Pacific Northwest east to the northern Great Plains, upper Mississippi valley and Great Lakes and below average rain and above average temperatures in the southeast, gulf coast, central and southern Great Plains, southwest and much of California. According to the National Weather Service's Climate Prediction Center, these conditions are likely to persist through the winter of 2017-2018, with a return to ENSO-neutral conditions in the mid to late spring.
LaNina Wintertime Pattern. From https://www.pmel.noaa.gov/elnino/what-is-la-nina.
So where does that leave our gardens and landscapes? Dry, dry, dry.
Evergreen plants are often the hardest hit by La Niña because they continue to use water for photosynthesis. Deciduous trees and shrubs require less moisture, but will benefit from some irrigation during periods of little to no rain. Remember, infrequent deep irrigation is better than frequent shallow irrigation. Don't forget to water your container plants as well.
Although many of our plants are in a resting period right now, they aren't totally shut down, and their roots still need moisture to stay hydrated and keep living plant tissue functioning. Without rain, roots can desiccate and die. And the little rain we've had has encouraged the weed seeds to start germinating, which further uses up what little moisture is in the soil. Pulling weeds and mulching around your plants will help to conserve water and keep plants stronger. Organic mulches such as bark or wood chips are best because they add organic matter to the soil as they decompose.
Mulch conserves moisture around landscape plants.
Warmer temperatures sometimes cause shrubs to start putting out leaves early and while there's not much to do about that, be on guard for cold snaps that will freeze tender new growth. Before a freeze, water your plants, as soil moisture and hydrated roots will improve their cold hardiness.
In summary, La Niña has put us back in drought conditions. Unfortunately, we've had a lot of experience with drought here in central California.
For La Niña forecast information, visit the National Weather Service's Climate Prediction Center. For reminders on gardening in a drought, visit the UC California Garden Web. Don't forget to subscribe to our blog so that you receive an email notification when a new post goes up. If you have questions, contact us online, by phone or in person to get answers to your gardening quandaries.