It got cold. Even colder than forecast. Five out of six nights over the past week saw sub-freezing temperatures. Friday night it was 29F as early as 10:30 p.m. and it was 26 as late as 6:30 a.m. Saturday and not above freezing till about 8:20. That is a lot of cold for the time of year, especially given that this time of year is bloom season for almonds and many stone fruit.
The most sensitive trees I have here are two citrus trees. This is how I covered the ‘Gold Nugget’ mandarin. In addition to this tent, I have a string of lights on the tree (note orange extension cord). I placed a hi-lo thermometer inside. The temperature under the tent never reached freezing, thanks to the heat from the lights and the thick greenhouse-style plastic.
The other one I always protect in freezes is the ‘Wekiwa‘ tangelolo. In addition to this plastic over a frame, inside I have placed not only a string of lights but also a heat lamp (the kind made to keep chicks warm). On that cold Friday-Saturday, the lowest it got in here was 39.
Note the new leaf shoots at the top of the branches. These are what I was most worried about, as this is where flower buds will form soon. This variety may be hardy down to the low 20s (and this tree did survive 20F, albeit with extensive damage, without a heat source in Dec. 2013). But new growth would not take well to repeated freeze exposure.
Blooms of deciduous fruit and nut trees also do not take well to freezes. Many such trees were already breaking dormancy when the cold struck. My ‘Flavor Delight’ aprium was in bloom by about the 15th of the month. All signs were encouraging for good fruit this year, after a year when it did not fruit (due to heavy rain during this time of year in 2017).
Immediately after the freeze, the tree looks like this:
The flowers have all collapsed. They were near the end of their bloom anyway, but this dramatic a collapse likely means major damage. There also are no leaf shoots, as there normally would be as the bloom wraps up. There are a few buds in evidence, and the tree itself likely will be fine. But I certainly would not count on any fruit. Many other stone fruits had buds swelling before the freeze, and those could have been rendered non-viable by cold temperatures.
As I said in the earlier post in anticipation of the freeze, I do not have to count on fruit and nut trees for income. For those that do, this past week has been very rough. Almond growers, whose trees reach peak bloom around this time, are looking at substantial damage. Some will come through OK, others may have total losses. It will be a while before a full damage assessment can be made. If you like almonds, expect to pay more for them this year. California’s Central Valley produces most of the world’s supply. The effects of this freeze will reach far.