The Reality of Growing Palms in Northern California

[Mauna Kea Cloudforest]

For anyone growing palms and exotics in Central and Northern California, the evil 1990 freeze looms heavy in the history of horticulture in this part of the State. It took a good 10 years for people to forget and start planting tropicals again. Does anyone even dare take a look? Any plant that survived the 1990 freeze would actually have qualified to grow in Washington State. The truth is, for all palm collectors North of Point Conception, a 1990 style freeze would easily devastate 80-90% of a collection unless one is prepared to deal with something like that.

As I am getting ready to haul a truckload of palms from Southern California, 30% of which will be zone pushers, I began to wonder, what would I do if I was faced with a 1990 style freeze. I managed to deal with 1998, which had temps at 32F at Sunset and 27F by sunrise. 2007 bypassed us altogether and hit folks down south hard. I can deal with the average radiational freeze that seems to show up every 7-10 years, I've carefully planted in such a way that things can survive. I try not to be in zone denial and garden in a zone 9b fashion, planting anything under canopy that can't weather 29F out in the open without damage. But a 1990 style freeze is an entirely different matter, and should it happen again, either I am prepared, or else the losses would be so terrific that I would probably want to sell my house and move to Hawaii.

To give you a glimpse of what happened in Santa Cruz, I managed to dig up the hourly reading from the CIMIS station that sits in the middle of the Delaveaga Golf Course a little North of town. It's at 300 feet elevation and is the closest to what I would ever be dealing with. I appended the raw data at the end of this post. On 12/21/1990, the temperature was already at 32F by 6PM after sunset and plummeted for the rest of the night bottoming out at 24.5F, not coming back up above 32F before 10AM. Whatever froze probably didn't get much of a chance to thaw as it barely made it to 43F by 3PM the following day, dropping below 32F after sunset and this time, plummeting down to 23F by 6PM the following Morning, and not rebounding back up above freezing by 10AM.

Any guesses as to what would happen to most zone 9b palms in this sort of freeze? Kings? Flame throwers? dypsis baronii? Without protection, a chnuk of my garden would basically be toast. Now I know how to protect my tropical fruit trees, they're all kept to small sizes. I have scaffolding that gets thrown into place, a chunk of floating row cover, and a convection propane heater underneath to save my citrus orchard. But how does one protect palms that have 20 feet of trunk? What the heck do you people in Florida do with this sort of freeze? Keep in mind, it lasted only two days! Two freakin' days to wipe out your entire garden, just like a fire storm, or a flood. This freeze took out mature ficus trees all over Silicon valley. It was no laughing matter.

In the Central Valley it was so cold that temps stayed below freezing during the day, and it was no longer even considered a radiational freeze, but a convection freeze, i.e. no inversion layer whatsoever. And while the worst of it lasted two days in Santa Cruz, with minor radiational freezes down to 29F for 2-3 hours the following two weeks, it dropped to 22F for two weeks in a row, and the worst of it it was below freezing during the day! I also posted the data for Modesto.

Anybody make domes that fit over entire gardens?

Santa Cruz Delaveaga

12/21/90 1700 35.1

12/21/90 1800 31.2

12/21/90 1900 29.6

12/21/90 2000 29

12/21/90 2100 28.5

12/21/90 2200 27.6

12/21/90 2300 26.9

12/21/90 2400 26.2

12/22/90 100 25.9

12/22/90 200 25.4

12/22/90 300 24.9

12/22/90 400 24.6

12/22/90 500 24.5

12/22/90 600 24.5

12/22/90 700 24.1

12/22/90 800 24.2

12/22/90 900 27.6

12/22/90 1000 32.4

12/22/90 1100 36.6

12/22/90 1200 39.7

12/22/90 1300 40.6

12/22/90 1400 41.3

12/22/90 1500 42.6

12/22/90 1600 41.9

12/22/90 1700 39.1

12/22/90 1800 33.5

12/22/90 1900 30.7

12/22/90 2000 30.3

12/22/90 2100 29.5

12/22/90 2200 28.4

12/22/90 2300 26.2

12/22/90 2400 26.1

12/23/90 100 25.2

12/23/90 200 25.1

12/23/90 300 25.2

12/23/90 400 23.5

12/23/90 500 23.7

12/23/90 600 22.9

12/23/90 700 23.3

12/23/90 800 23.4

12/23/90 900 26.1

12/23/90 1000 33.9

12/23/90 1100 40.9

Modesto

12/20/90 1800 33.9

12/20/90 1900 31.7

12/20/90 2000 30.5

12/20/90 2100 30.5

12/20/90 2200 31.5

12/20/90 2300 29.6

12/20/90 2400 29.9

12/21/90 100 27.9

12/21/90 200 31

12/21/90 300 31.3

12/21/90 400 30.2

12/21/90 500 28.8

12/21/90 600 26.9

12/21/90 700 24.8

12/21/90 800 24

12/21/90 900 25.7

12/21/90 1000 27.1

12/21/90 1100 29

12/21/90 1200 30.6

12/21/90 1300 32

12/21/90 1400 33.2

12/21/90 1500 33.8

12/21/90 1600 33.1

12/21/90 1700 29.3

12/21/90 1800 24.1

12/21/90 1900 22.3

12/21/90 2000 20.4

12/21/90 2100 19.5

12/21/90 2200 21.3

12/21/90 2300 22

12/21/90 2400 21.8

12/22/90 100 20.5

12/22/90 200 19.1

12/22/90 300 18.9

12/22/90 400 19

12/22/90 500 18.5

12/22/90 600 18

12/22/90 700 17.9

12/22/90 800 17.5

12/22/90 900 22.3

12/22/90 1000 25

12/22/90 1100 27.3

12/22/90 1200 29.5

12/22/90 1300 31.4

12/22/90 1400 33

12/22/90 1500 34.2

12/22/90 1600 34.9

12/22/90 1700 32.2

12/22/90 1800 26.5

12/22/90 1900 24.9

12/22/90 2000 21.3

12/22/90 2100 20.4

12/22/90 2200 19.9

12/22/90 2300 18.7

12/22/90 2400 17.4

12/23/90 100 16.8

12/23/90 200 17.4

12/23/90 300 16.8

12/23/90 400 16

12/23/90 500 15.3

12/23/90 600 15.4

12/23/90 700 14.1

12/23/90 800 15.5

12/23/90 900 21.6

12/23/90 1000 28

12/23/90 1100 32.1

12/23/90 1200 34.7

12/23/90 1300 37.2

12/23/90 1400 37.9

12/23/90 1500 38.7

12/23/90 1600 38.6

12/23/90 1700 35.2

12/23/90 1800 29.7

12/23/90 1900 27.5

12/23/90 2000 25.3

12/23/90 2100 24.3

12/23/90 2200 23

12/23/90 2300 22.3

12/23/90 2400 20.6

12/24/90 100 18.9

12/24/90 200 18.6

12/24/90 300 17.8

12/24/90 400 16.4

12/24/90 500 15.9

12/24/90 600 14.6

12/24/90 700 16.1

12/24/90 800 14.8

12/24/90 900 22.3

12/24/90 1000 30.3

12/24/90 1100 34.9

12/24/90 1200 38.5

12/24/90 1300 40.4

12/24/90 1400 42.2

12/24/90 1500 43.3

12/24/90 1600 43.4

12/24/90 1700 40.4

12/24/90 1800 32.5

12/24/90 1900 28.4

12/24/90 2000 25.5

12/24/90 2100 22.7

12/24/90 2200 22.6

12/24/90 2300 20.4

12/24/90 2400 20.4

12/25/90 100 18.9

12/25/90 200 19

12/25/90 300 18.6

12/25/90 400 18.3

12/25/90 500 18

12/25/90 600 18.3

12/25/90 700 17.8

12/25/90 800 18.7

12/25/90 900 24.9

12/25/90 1000 31.7

12/25/90 1100 37.2

12/25/90 1200 40.9

12/25/90 1300 43.8

12/25/90 1400 45.5

12/25/90 1500 46.3

12/25/90 1600 46.3

12/25/90 1700 42.8

12/25/90 1800 36.9

12/25/90 1900 33.9

12/25/90 2000 29.4

12/25/90 2100 27

12/25/90 2200 25.4

12/25/90 2300 23.3

12/25/90 2400 22

12/26/90 100 23.6

12/26/90 200 21.3

12/26/90 300 20.7

12/26/90 400 21.3

12/26/90 500 21

12/26/90 600 21.6

12/26/90 700 19.9

12/26/90 800 21

12/26/90 900 27.5

12/26/90 1000 34.6

12/26/90 1100 39.9

12/26/90 1200 43.8

12/26/90 1300 47.3

12/26/90 1400 50

12/26/90 1500 51.1

12/26/90 1600 51.3

12/26/90 1700 46.3

12/26/90 1800 39

12/26/90 1900 34.1

12/26/90 2000 32.4

12/26/90 2100 29.6

12/26/90 2200 27.2

12/26/90 2300 29.3

12/26/90 2400 26.5

12/27/90 100 25.8

12/27/90 200 25.3

12/27/90 300 24.8

12/27/90 400 24.1

12/27/90 500 24

12/27/90 600 22.2

12/27/90 700 23.5

12/27/90 800 23.5

12/27/90 900 27.4

12/27/90 1000 34

12/27/90 1100 40.1

12/27/90 1200 46.2

12/27/90 1300 48.9

12/27/90 1400 51.8

12/27/90 1500 52.3

12/27/90 1600 51.4

12/27/90 1700 46.4

12/27/90 1800 41.7

12/27/90 1900 35.7

12/27/90 2000 32.8

12/27/90 2100 29.3

12/27/90 2200 26.9

12/27/90 2300 24.9

12/27/90 2400 26.4

12/28/90 100 24.4

12/28/90 200 25.5

12/28/90 300 24.2

12/28/90 400 22

12/28/90 500 21.4

12/28/90 600 21.6

12/28/90 700 23.1

12/28/90 800 22.9

12/28/90 900 28.2

12/28/90 1000 35.2

12/28/90 1100 42

[Sutter Bob]

Interesting data and a sobering reminder of how cold it can get around here.

It definitely keeps some perspective on what one might plant as far as long-term elements of a palm garden.

The concept of infrastructure palms is occasionally mentioned on Palmtalk and I think it's a good theory to keep in mind.

I tend to think of infrastructure palms as specimens which will be around for the long haul (i.e. survive the worst likely climatic conditions expected for an area over decades). I also tend to think of them as potentially providing canopy for smaller and more tender species.

With that in mind, we still have well over a dozen species that could be considered for that role in many areas of northern California.

Some of the faster growing borderline species can certainly be used to add some variety, but obviously we should expect to be disappointed from time to time when they don't make it.

[trioderob]

you think THATS bad ? - try this on for size as to what could happen in California weather wise:

In Southern California, beginning on December 24, 1861, it rained for almost four weeks for a total of 35 inches at Los Angeles. In the San Gabriel Mountains the mining town of Eldoradoville was washed away by flood waters.^[15] The flooding drowned thousands of cattle and washed away fruit trees and vineyards that grew along the Los Angeles River. No mail was received at Los Angeles for five weeks. The Los Angeles Star reported that:

The road from Tejon, we hear, has been almost washed away. The San Fernando mountain cannot be crossed except by the old trail ... over the top of the mountain. The plain has been cut up into gulches and arroyos, and streams are rushing down every declivity. ^[16]

The plains of Los Angeles County, at the time a marshy area with many small lakes and several meandering streams from the mountains, were extensively flooded, and much of the agricultural development which lay along the rivers was ruined. In most of the lower areas small settlements were submerged. These flooded areas formed into a large lake system with many small streams and a few more powerful currents cut channels across the plain and carried the runoff to the sea.

At Santa Barbara County the narrow coastal plains were flooded by the rivers coming out of the mountains, and the town of Ventura was abandoned.

In San Bernardino County, all the fertile riverside fields and all but the church and one house of the New Mexican colony of Agua Mansa, were swept away by the Santa Ana River, which overflowed its banks. The ringing church bell on the night of January 22, 1862 alerted the inhabitants to the approach of the flood, and all escaped.^[17]

Downriver in Los Angeles County, (including what is now Orange County) the flooding Santa Ana River created an inland sea lasting about three weeks with water standing 4 feet (1.2 m) deep up to 4 miles (6 km) from the river.^[12] In February 1862, the Los Angeles, San Gabriel, and Santa Ana Rivers merged. Government surveys at the time indicated that a solid expanse of water covered the area from Signal Hill to Huntington Beach, a distance of approximately eighteen miles.

In San Diego a storm at sea, backed up the flood water running into the bay from the San Diego River, resulting in a new river channel cut into San Diego Harbor. The continuous heavy downpour also changed the look of the land, the previously rounded hills were extensively cut by gulleys and canyons.^[18]

[trioderob]

and the Capital was hit even worse - behold this painting and ask yourself this question

what if this happened in 2014 ?

In the Sierra Nevada foothills truly extraordinary amounts of precipitation were reported including 102” in the mining town of Sonora over the two-month period. Flooding that had begun during the December deluges increased in scope and intensity throughout January. The capital city of Sacramento was flooded by ten feet of water and the new governor had to travel to his inauguration in a rowboat.

Edited March 20, 2013 by trioderob

[Sutter Bob]

For sure.

Ten major floods around here in last century.

And we think we're in control.

[Mauna Kea Cloudforest]

Now these comparisons actually make sense. The 1990 freeze was so far off the charts that it really does correspond to the equivalent of a flood, bad earthquake and fire, all of which any California garden really isn't immune to.

I don't garden according to the 1990 freeze as a measure of what can grow here, because if I did, I think I'd grow just apples and maples. But it's still good to look at what can happen and be somewhat prepared.

But I also agree, the backbone of bullet proof palms goes a long way to making the pain of loosing a 30 year old 10 foot of trunk rhopie bearable. Although not sure they would die because a friend of mine had one come back after 1990 after experiencing 19F. (r. sapida, not baueri).

[Sutter Bob]

Speaking of Rhopies, give them a bit of shade and water here and they seem to just keep growing, even after getting beaten up every winter.

[JasonD]

In places like inland Sonoma and Napa county, and even in the coldest stretch of the Santa Clara Valley south of San Jose, the flawless, bulletproof palms are Jubaea, Butia, Brahea, Trachycarpus, Trithrinax, Chamaerops, not Syagrus or even Washingtonia robusta, which suffer frequent (every 3-6 year) seasonal discoloration and outright disfigurement, though they are by far the most common. It's a matter of taste, I guess. The look of healthy green foliage on palms in February pleases me.

[Central Floridave]

"What the heck do you people in Florida do with this sort of freeze?"

I always say if we get walloped by a freeze, I'll just replant. I know whatever tropical I have in the yard is only temporary.

Generally though, after a freeze, evergreen tree sales go up and tropicals go down. Then after a year or two, people forget and replant tropicals. Its a vicious cycle! But, I've given up on the ultra-tropical like Betal nut and red sealing wax palms. Need a greenhouse for those. That may be my next obsession!

[Mauna Kea Cloudforest]

Jason, you forgot sabals and the hardy parajubaeas. The current palm backbone I have looks fantastic right through the Winter. This is why I was puzzled why all these Southern California growers were complaining about yellowing palms. Not a single one of my palm is yellow.

Then there are the oceania palms that all stay vibrant through the cold: Lorde Howe Island. New Caledonia, New Zealand. All that stuff stays vibrant and in full growth mode here.

It's easy to keep palms from going yellow in the Winter. Just use calcium nitrate to fertilize instead of ammonium nitrate. The bacteria in cold soil cannot process ammonium nitrate. But calcium nitrate is still consumed even when the soil drops below 55F.

Better yet, use organic fertilizer. Even my chamberyonia grows in our high chill Santa Cruz weather with soil temps below 55F.

In places like inland Sonoma and Napa county, and even in the coldest stretch of the Santa Clara Valley south of San Jose, the flawless, bulletproof palms are Jubaea, Butia, Brahea, Trachycarpus, Trithrinax, Chamaerops, not Syagrus or even Washingtonia robusta, which suffer frequent (every 3-6 year) seasonal discoloration and outright disfigurement, though they are by far the most common. It's a matter of taste, I guess. The look of healthy green foliage on palms in February pleases me.