A couple more days and it’s March, in which starts spring. But before we move on, I’ve pulled three lessons from the past winter.

1. Consequences of 28 degrees

The coldest night of this 2021-2022 winter in Southern California just passed, on February 23-24. My yard’s weather station dropped to 28.2 degrees. What were the consequences? The lower part of my yard was covered in frost, including the encelia californica flowers above. Most of my vegetables were also covered in ice crystals.

Romaine lettuce, icy.

Most of these vegetables weren’t damaged, however. The lettuce, brassicas, peas, carrots, onions, garlic, parsely, cilantro, beets, parsnips, and spinach in my garden did not care.

Potatoes couldn’t handle it though. Potato foliage turned to brown mush, which is why it’s best in colder locations like mine to plant potatoes in February but not have them up and growing earlier in winter.

No damage was done to citrus by a drop to 28 degrees, except that succulent new growth on one lemon rootstock was partially melted.

Rough lemon rootstock.
Rough lemon rootstock fresh growth melted.

Some avocados had leaf mottling and burning of some new leaves and some emerging flowers, but fruit was all unharmed.

Cold damage on #86 (aka ‘Koala’) avocado leaves.

I share this lesson despite knowing that most of you did not experience temperatures so low in your garden because you might like to know what will happen if you ever do — and what won’t happen so you’re not unnecessarily frightened if you ever see a forecast for 28 degrees at your place.

2. Hass did not get enough water

It is in winter that you judge your previous summer’s watering of avocado trees. As I look at my avocado trees, the watering was sufficient on most (as judged by the amount of brown on leaves), but it is downright painful to look at this Hass tree.

Hass avocado tree with bad leaf burn in winter.

Throughout summer it looked fine and I thought I had been watering it enough. Clearly, I was wrong.

The challenge with this particular tree is that it is triangulated by a large live oak tree, a large Valencia orange tree, and a large grapevine. All three of these large plants have expansive, strong root systems that have invaded the territory of the Hass and steal some of the water I apply under it. I know this because I have dug around and found the roots of these plants under the Hass. It has been happening for years.

Further, I noticed this last summer how much the grapevine by the Hass grew compared to other grapevines in the yard. Here is a photo showing the grapevines in July. The farthest vine is the one next to the Hass tree. Note its mass of growth.

Grapevines in July, 2021.

The oak near the Hass likewise looks healthier than other oaks in the yard and produced an abundance of acorns.

The acorn-laden oak in late September. The Hass tree is just out of the picture to the right.

To pour salt in the wound of this Hass tree, my chickens’ favorite place to hang out is under the its canopy where they continually scratch and damage the avocado’s shallow roots. (Oaks, oranges, and grapes all root more deeply by comparison.)

What do I do now? I already cut down the grapevine. I pruned the oak a bit, but that’s all I will do to that tree; I prize this big oak more than the Hass tree, frankly. I plan to water the orange tree more. And this coming spring-summer-fall I will water the Hass with more volume and over a broader area. Lastly, I’m going to add some netting under the Hass tree so that the chickens can’t scratch and damage its roots as much.

Can’t wait to see how effective these remedies are. Look forward to seeing how the Hass looks next February compared to now.

3. Early chill matters most

We know that certain deciduous fruit trees that we grow in Southern California don’t flower and fruit well if our winter weather is too warm. (They need “chill hours.”) So we might expect poor performances from these trees this year since January through mid-February saw daytime temps mostly in the 70s and nighttime temps mild too, not feeling like a chilly winter.

January through mid-February, too, had only 0.15 inches of rain at my place. I’m sure yours was similarly dry. It was a stretch of very comfortable gardening weather, not the kind of weather that you’d think would encourage trees to go dormant.

Nevertheless, here in late February trees are beginning to bloom well – not phenomenally well, but well.

Satisfactory bloom on a branch of Candy Heart pluerry.

Why? Recall October, November, and December. We came down from summer fast. Our first rain was at the very beginning of October, on October 4. And from there we never had a fall heat wave. Even though November was dry, it wasn’t too warm, and then December was full of storms (and frost in my yard). December ended with 6.5 inches of rain, well above average.

So this year’s weather pattern seems to confirm the idea that cool weather in late fall and early winter is what deciduous fruit trees need in order to flower and fruit well more than continual cold weather through the middle and end of winter. In other words, how we enter winter seems to determine more in this regard compared to how we exit winter.

(For comparison, see my observations of trees after a winter that started dry and warm in “Effects of a warm and wacky winter on deciduous fruit trees.”)

(Also see observations of trees during a consistently cool winter in “Messages from your deciduous fruit trees after the chilly winter.”)

There’s always more to learn out there. I love keeping my eyes open and following along with what nature has to teach us.

All of my Yard Posts are listed HERE

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