15 replies to this topic

[insipidtoast]

This USDA zone map perplexed me the other day.
http://www.arborday....media/zones.cfm
If you look at the area around the Colorado River between California and Arizona, there is clearly a large landmass labelled as zone 10. How is that possible so far inland? I'm skeptical about the map, but it seems other maps corroborate this evidence: http://www.cliftyvie...da_map_full.jpg

As seen there as well, most of the area east and southeast from Palo Verde is labelled as zone 10.

http://www.arborday....media/zones.cfm

[Stevetoad]

my uncle has a house on the river just up from palo verde dam. it may be zone 10 for the day time avg temps but the nights are super cold during the winter. last time i went out there during the winter the low was 22f. the only palms that do good out there are washies, brahea and somewhat queens (they always look ratty).

[Mandrew968]

So they look like queens?

[Stevetoad]

So they look like queens?

haha BURN!!! there super ratty though. bad enough to where i like the washies better

[Jubaea]

That map does not take into account microclimates. I'm assuming down by the river the elevation drops compared to the surrounding area? This could account for the cold nights when there is no cloud cover and little to no wind. I would expect the extreme heat would do quite a bit of damage even if the cold spared some plants.

Check Out Yuma, AZ with the link below

http://www.weatherba...ates-of-America

Edited by Jubaea, 30 September 2011 - 08:20 AM.

[MattyB]

That's crazy! Could the Gulf of California have anything to do with it? Could the higher elevation of the Glamis sand dunes be the reason? For those of you who don't know, I've attached a pic of what some of this area looks like. If Yuma's all time low is 34F then there should be a palm growing frenzy out there with all that year round heat.

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[Jubaea]

I have seen other places say that the all time record low was 19 degrees F recorded in 1937 and on this weatherbase station it says it is 30 years of data. I'm not sure if this station is just in a great microclimate(which I hope) or if there is an error in the data. Yuma gets very little precipataion so that could be a problem for non-desert palms. I know that they grown mangos in the California Desert which would require a frost free climate. I don't think the Salton Sea would have much effect but you never know.

[JasonD]

That's crazy! Could the Gulf of California have anything to do with it? Could the higher elevation of the Glamis sand dunes be the reason? For those of you who don't know, I've attached a pic of what some of this area looks like. If Yuma's all time low is 34F then there should be a palm growing frenzy out there with all that year round heat.

If you look at the record over 63 years the average annual number of days attaining lows below 32F is ~16. The record lows date from a 30-year period.

[Xenon]

Here's a hardiness zone map by the NOAA using data from 1981-2010: NOAA Hardiness Zone Map (scroll to the middle of the page). It seems to be more detailed on the Zone 10 areas in inland California/Arizona as well as coastal Central Florida, South Texas looks about the same.

Jonathan

[MattyB]

That map seems more accurate with the SoCal desert all pretty much being zone 10 and then as you get into Arizona, only the mountain tops are dotted dark green for zone 10. For those who don't know the topography, the lighter green/colder strip that separates coastal san diego and los angeles from the eastern parts of the state, is our local mountain range.

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[bubba]

\The USDA has shown poor judgment in it's choice of criteria to gauge "cold hardiness" or "what grows". The average minimum temperature simply does not appropriately define "what grows". The best example of the system's uselessness is a steady climate in which the high is 45F.and the low is 40F., which constitutes a Zone 11. Somehow I doubt you would find the Coconuts and Sealing Wax Palms you would expect to grow in the tropical Zone 11.

The true gauge is the system previously used by the USDA and predominately used internationally to describe climate. That is Koeppen. What constitutes Tropical? A climate in which the average monthly temperature in the coldest month is 64F. or higher.Interestingly, this is the designation that most closely contours to where the Coconut grows.The range of the Coconut is the most honest attempt at the definition of Tropical and certainly not a constantly cold climate that achieves a Zone 11 designation because it never drops below 40F.

Beyond that, the climatic data presented on some of the sites appears inaccurate.I personally talked to the primary owner of the Keit Mango Farm after the 2007 Freeze.He is a wealthy guy and that operation is his labor of love.He told me that the average low temperature was 22F.during the Freeze in an area of the Ca. Desert picked specifically because of it's benign climate. There is no doubt in my mind that he would have picked Yuma if it's climate was less prone to Freeze.I am certain he quickly and at great cost imported new replacement trees.

Why the USDA picked a flawed and skewed system to demonstrate "what grows" is an interesting question. Particularly when you consider that they abandoned the internationally accepted system (Koeppen)in an effort to be different. I suppose it was an early attempt at bureacracy.

[happ]

Tend to agree with Bubba. There are even pockets of USDA zone 11 in southern California [I live in one] that never see frost but that has no impact on tropical plants because of so many other factors such as low humidity, overnight temps, lack of summer rainfall, damaging Santa Ana winds, etc. I'm out in the Coachella Valley regularly and never see half the number of palm species we grow on the coastal side of the mountains. The intense summer heat would kill wodyetia, ravenea, ptychosperma, pritchardia, hyophorbe, caryota, howea, etc.

[Patrick]

Uhhhhhhh,,,, "I'm from the government, I'm here to help?"

I tend to believe nothing of what I hear and half of what I see, but when it comes to the govt., it's neither of either.

[paulgila]

'specially them revenooers!

[insipidtoast]

That map does not take into account microclimates. I'm assuming down by the river the elevation drops compared to the surrounding area? This could account for the cold nights when there is no cloud cover and little to no wind. I would expect the extreme heat would do quite a bit of damage even if the cold spared some plants.

Check Out Yuma, AZ with the link below

http://www.weatherba...ates-of-America

Lowest Recorded Temperature Years on Record: 30
YEAR Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.
°F 34.5 34.5 37.8 41.7 46.1 53.8 61.7 70.1 69.9 61.6 51.8 42.2 36.4

This indicates a solid zone 10. Didn't even get to 32.

Obviously, none of these areas should grow tropical plants. Mangos sound like a nice novelty, but I probably wouldn't be able to afford the water bill. What intrigues me the most about these zone 10s and zone 11s!?? is that there are many interesting desert plants from around the world that could be grown there. There are many plants from the kahalari that could probably be grown with just minimal water in our deserts, and there are plants from north africa as well such as Hyphaene thebaica that could be easily grown in the absence of cold temperatures.

Here's a picture of the Yuma Proving Ground, which looks to be right in the middle of the Zone 10 blob:

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Edited by insipidtoast, 06 October 2011 - 08:28 AM.

[Cristóbal]

I am in this week working in the mexicali valley i work here one week of every month for 7 years. I have friends here with dates orchard. It is little more hot here than yuma arizona but same climate. Bataques Baja California by Mexicali is the most dry place with people in north america. I can say most years it is not more cold then 2 or 3 C for low temperature in winter 35 - 40 F but the big problem is very low humidetys 5-10 perecent strong winds all the time and some hot nights of summer not more cool than 35C 95F. In 2008 i plant in the spring one cocos nucifera to do some experiment. In august of same year it is dead. Too hot at night i think. There are not many plants that can grow here. The climate here is bad for people and almost all plants. You can read of my experiment of the cocos nucifera with many fotos here: Cocos Nucifera Mexicali Valley

Edited by Cristóbal, 06 October 2011 - 08:54 AM.