Planting Desert Trees IN the Swales

I live in Joshua Tree, CA (4 inches of rain per year, if we're lucky!) and am getting ready to put in some swales and plant some desert native food producing trees like mesquite. I've heard a number of times that in the desert trees should be planted inside the swales and not on the downhill berm side as is usual. I'd like to know more about this and the logistics of it. Can anyone help me out?

Mesquite is a very thirsty tree. A single tree can cover nearly an acre with its roots.
They don't share well. They have been blamed for erosion...not even weeds can grow around a thirsty mesquite.

I would be very cautious planting mesquite in arid regions. The can lower the water table.

I believe you might be referring to Chilean Mesquite - a shallow rooted hybrid. I've planted Honey and Screwbean which are native to this area and very deep rooted. These are wonderful nitrogen fixers. The beans are extremely nutritious and were one of the main food source of the Cahuilla tribe.

John Polk wrote:Mesquite is a very thirsty tree. A single tree can cover nearly an acre with its roots.
They don't share well. They have been blamed for erosion...not even weeds can grow around a thirsty mesquite.

I would be very cautious planting mesquite in arid regions. The can lower the water table.

1) I would be very cautious planting mesquite in arid regions. False - This is their native habitat after all.
2) The can lower the water table. False - They will drink far less water than the millions of gallons that are dumped on our fields annually. Mesquite is an extremely hardy, drought-tolerant plant because it can draw water from deep in the earth through its long taproot (recorded at up to 58 m (190 ft) depth). It can also use water in the upper part of the ground, depending upon availability. The tree can easily and rapidly switch from using one water source to the other. In Fact: to much water will drown a mesquite.
3) not even weeds can grow around a thirsty mesquite. False - Mesquite is a phreatophyte, which means it has deep roots and transpires efficiently. For this reason, one method of managing water loss in arid areas is the removal of mesquite. This is for the benefit of traditional agriculture, and does not apply to a properly maintained ecosystem created using permaculture.
4) They have been blamed for erosion...to remove blame from the agriculture system that actually caused it in the south west. - The root system of mesquite is good at keeping soil from being lost to runoff.
5) A single tree can cover nearly an acre with its roots. True (if your tree is over 1000 years old.) - these trees prefer burrowing their taproots deep into the earth not spreading across it, though often the root systems of these trees will be 2-3 times larger than the tree itself.

The benefits:

The tree's flowers provide a nectar source for bees to produce mesquite honey (monofloral honey), which has a characteristic flavor. The bean pods of the mesquite can be dried and ground into flour, adding a sweet, nutty taste to breads, or used to make jelly or wine. When used in baking, the mesquite bean flour is used in combination with other flours – substitute ¼ cup-to-½ cup mesquite flour in each cup grain flour. Mesquite bean flour is used in breads, pancakes, muffins, cakes and even cookies. Mesquite powder is also high in calcium, magnesium, potassium, iron and zinc, and is rich in the amino acid lysine.

Mesquite trees grow quickly and furnish shade and wildlife habitat where other trees will not grow. Being a legume, it fixes nitrogen in the soil where it grows, improving soil fertility. Mesquite wood is hard, allowing it to be used for furniture and implements. Wood from Prosopis juliflora and Prosopis glandulosa is used for decorative woodworking and woodturning. It is highly desirable due to its dimensional stability after being fully cured. The hard, dense lumber is also sold as "Texas Ironwood" and is rather harsh on chain saws and other tools. As firewood, mesquite burns slowly and very hot. When used to barbecue, the smoke from the wood adds a distinct flavor to the food. This is common in the Southwest and Texas-style barbecue. Mesquite-wood roasting or grilling is used to smoke-flavor steaks, chicken, pork, and fish. Mesquite smoke flavoring can be added to vegetable stir-fries, scrambled eggs, soups, and even ice cream. Additionally he plant's bud regeneration zone can extend down to 6 in (150 mm) below ground level; the tree can regenerate from a piece of root left in the soil. meaning that you can potentially harvest the wood from the same plant for many years.

Here is a document which may help you find your Prosopis selection. This is specifically about the main verities found in south america. Specifically Brazil and Peru. The interesting thing is that these trees formation is more a matter of the conditions they are grown in rather than their genus. Page 54/98 in this document will illustrate this. ( http://www.arch.cam.ac.uk/dgb27/chapter-3.pdf ) Also found in this document is information about the importance of pruning. (Page 49/93).

I have to agree with this quotation from the document. There is hardly any soil, if it is not habitually damp, in which the mesquite cannot grow; no hill too rocky or broken, no flat too sandy or saline, no dune too shifting...to entirely exclude it.

If you look around at local trees that are thriving, you will see that they manage to find where the water pools up or sinks underground. On the road east out of Amboy, there is a lone palo verde tree, which has the ignominy of being a shoe tree:



You will notice that it is right on top of a culvert that was put in to channel flash floods under the road. It's the only native desert tree for miles around, until you turn up the Kelbaker road and there are smoke trees growing in the wash. Apparently, being on the side of this culvert, it gets enough water to thrive.

In my observations of the desert southwest, there is a world of difference between 4" of rain a year and 10" or 12", like they get in Tucson. The further east you go, the better the palo verde does, because there is more summer monsoon rain. While Las Vegas might get one good rain in the summer, Tucson has an actual rainy season in July and August when they can rack up 4". If you want to get those mesquites and palo verdes to really thrive, put some sort of catchment downhill from them, and simulate a good late summer drenching.

For what it's worth, when they plant palo verdes as landscaping in Henderson, NV, they put them in the swale, not below a berm.

Good for Palo I guess. They generally live in washes, because they need more water. Mesquite on the other hand will probably do better on the top most swale bank. Good as the zone 5 edge. I would not use mesquite directly in swale or on and below Burma.

Hi Jill,

What kind of swale furniture you put in will depend on your catchment. My swales are 130 cm deep and i've planted on the "hill" side of it, because when i do get rain (which hasn't happened since January 2011) the swales will have a full meter of water in them, and not all the trees i have can cope with that kind of inundation.

Neal
www.albaydha.org

Hi Jill:

Glad to see someone else doing good work in an arid landscape!

Like Neal said, it does depend on catchment area and slope how you design your swales. Here in Phoenix, I live near the low spot of our Valley of the Sun - on the historic alluvial floodplain of the Salt River (flat land). My water catchment is a variation of swales for flat lands - infiltration basins. More water intensive trees get planted IN the basin and those that are heartier get planted on the slopes or top of the basin. I do have a fruit tree swale along one side of my house filled with deciduous stone fruits and the like - these are planted IN the swale. My mistake was to plant them at the very bottom and not slightly on one of the slopes of the swale - but still - even after a 2" rain event (huge for us) this area soaked in all the water very quickly. It should be noted that this area has a fairly large catchment as there is a French drain in this swale fed by the neighbor's VERY LARGE carport/patio roof. The fruit trees LOVE it.

If you don't already have them, get Brad Lancaster's "Rainwater Harvesting for Drylands and Beyond" books - Vol 2 is all about water storage in soils.

Do you have any pics of your project?

I was enthusiastic early on about Mesquite, and collected seed from some local trees while I was visiting near Phoenix. Unfortunately what I found out was that all my two year-old seedlings were killed by my Sierra winter cold at 5000 feet. The winter lows in my area can drop to about +15F, but my trees themselves seem to be reacting more like it's Zone 6. Is anyone aware of a local stock of extra cold hardy Mequite from which seed could be harvested? My other option is taking a road trip to Flagstaff and just stopping at the hightest altitude mequite grove I can find.

Hi Michael,

First off - sorry about your trees

I think they may have been killed just due to their age, more than anything else. For several winters now, Phoenix has had some pretty cold weather (last year, the pipes in my outdoor shower burst!) - yet my mesquites live on. One is some kind of hybrid mutt mesquite, the other two are screwbean. If you have a chance to harvest seed from a high altitude mesquite bosc, do it! That would be your best bet. Another source of seeds is the University of Arizona Desert Legume Program - they get seeds from all over the place and test them out in their fields in Tucson. They have seeds to share and data to indicate how well they hold up to temps, sun, water (or lack thereof).

Jennifer Wadsworth wrote:
I think they may have been killed just due to their age, more than anything else. For several winters now, Phoenix has had some pretty cold weather (last year, the pipes in my outdoor shower burst!) - yet my mesquites live on.

It's been a work in progress. To go into a little more depth, we have a suburban home in southern California, and our homestead land in the Sierra foothills at 5000 feet. I've cruised though backyards, parking lots, and botanical gardens, finding seeds from various trees that I think might be beneficial. Got some California Black Walnut that is now in the ground. Have also in the past tried Carob, Black Locust, Mesquite, and Honey Locust. The carob was from the parking lot of the Palms Springs airport. Mesquite from a roadside tree near Phoenix. Black Locust from a university garden, and Honey Locust a combination of lawn shade trees, and store bought grafted (high sugar pods).

I usually sprout seeds in the kitchen window after scarifying the seed. This gets transplanted into 16 oz soda cups (recycled), and then into 5 gallon pots. I usually keep the seedlings in the back yard for about two years before planting, so they are NOT delicate little sprouts. The carob and mesquite appear to have been killed by the winter cold. The carob never lasted more than 1 winter. The mesquite was slightly more hardy, but died down to the root collar that resprouted the next year. The second winter in the ground killed of what was left of the mesquite plants.

The Black Locusts were all killed off by deer. They loved the taste of locust and eat them right down to the ground. At first I thought that their natural thorniness would protect them. Guess that was wishful thinking.

Now Honey Locust is the next attempt. I've got two year old seedlings ready to go in the ground next spring. Will try to protect them with something like this, which is what I used to keep the deer off my fruit trees.

Each tree gets planted in a wire pot in the ground. This keeps the gophers from tunneling up to eat the roots. The drain pipe around the trunks prevent mice from debarking the trees, and the chicken wire keeps off the deer. Even the chicken wire though hasn't stopped the raccoons, and I've lost 100% of my emergent fruit crops to animal thieves!

BTW, I've also experimented with very cold hardy citrus varieties, like Yuzu, Citrange, Shungjuan, and Trifoliate Orange. The trifoliate is the only thing that has survived the winters intact. Will have to experiment with better winter insulation. Tried wrapping some trees in bubble plastic, but those trees were the first to die, probably because they got cooked by the winter sun.

I've had problems getting Palo Verde trees to survive in 8a. They freeze to the ground every year. I have had success with Chilean Mesquite so far. I also have planted Jujubes with excellent success (so far) as well.

So i gather that you would advise against starting mesquite trees in ground if you're in a frost-prone region? I'm in the Victor Valley area, average annual low ~16F, average winter lows 32F.

re: the depth vs. spread of mesquite roots.

Aside from the difference in varieties, I've discovered that whether it is grown from seed or transplanted may have an effect, as well. Arizona native mesquite trees that are grown in a nursery can sometimes have their taproots damaged (or cut, according to some of the local Tucson, Arizona gardeners), and it does not grow back properly after planting, as i understand it. These trees may be more prone to spreading out like the chilean mesquites and also more prone to toppling during a heavy wind, especially during a heavy rainstorm.

I have not experienced this myself, but spoke to other gardeners who had run into this problem with their own mesquite trees.

But in regards to growing underneath the tree, I've had the best success with growing the majority of the more tender plants in my yard under mesquites. Many of the native plants do quite well underneath them as well.

Neal Spackman wrote:Hi Jill,

What kind of swale furniture you put in will depend on your catchment. My swales are 130 cm deep and i've planted on the "hill" side of it, because when i do get rain (which hasn't happened since January 2011) the swales will have a full meter of water in them, and not all the trees i have can cope with that kind of inundation.

Neal
www.albaydha.org

Hi Neal, I've been following the work at Albaydha on your website. I just posted another forum question and I would love to get your feedback. I'm doing permaculture in Joshua Tree, CA in the Mojave desert. We get about 4 to 6 inches a year of rain (if we're lucky). I want to capture and sink water from a water run off area on my land. It isn't a huge flush of water but more of a gentle flow down the land when it rains. I'm thinking of using a network of boomerang swales with a mesquite tree planted in each. I've read a lot of conflicting information about how far apart such swale rows should be from each other in arid lands. The area I have in mind has a gentle slope with a gradual 10' fall over a distance of approximately 150'. Any feedback would be greatly appreciated!

And to everyone else - thank you for the feedback. It really helped with the design that I finally used.

Another benefit to mesquite is that they are excellent animal fodder. I collect the pods and ferment them for pigs and poultry. They love them. Also, germination increases substantially after passing through an animal digestive system.

If you want to see the wonderful effects that trees have on the desert take a drive right now in the desert south west. I keep meaning to stop and take a picture, but you have really nice green grass under the trees and desert nothing out of the trees influence. It seems that most "wild" mesquite grows in the flood plain regions of rivers and washes and would do fine out of the swale.

You may want to look into "Stealth Ponds"

Where in you have a series of layers in your soil to hide water under a layer of dirt.

jill giegerich wrote:

Hi Neal, I've been following the work at Albaydha on your website. I just posted another forum question and I would love to get your feedback. I'm doing permaculture in Joshua Tree, CA in the Mojave desert. We get about 4 to 6 inches a year of rain (if we're lucky). I want to capture and sink water from a water run off area on my land. It isn't a huge flush of water but more of a gentle flow down the land when it rains. I'm thinking of using a network of boomerang swales with a mesquite tree planted in each. I've read a lot of conflicting information about how far apart such swale rows should be from each other in arid lands. The area I have in mind has a gentle slope with a gradual 10' fall over a distance of approximately 150'. Any feedback would be greatly appreciated!

And to everyone else - thank you for the feedback. It really helped with the design that I finally used.

Impossible to say without visiting or at least looking at some maps/pictures. Here are the questions you should be asking though: in a large rainfall event, how much runoff is going to hit your earthworks an dhow much will you be able to catch? What's downstream from you? Why boomerang berms/basins as opposed to keyline or contour swales? I spaced my swales based on the height of our canopy trees and the predicted amount of runoff we'd be able to catch. Boomerangs tend to be sunken (like Lanzarote), and are good as dew/fog catchers--do you get that out where you are in Joshua Tree?

Neal

Mesquite Trees - after glancing at the discussion about Mesquite trees - I'm confused. I had it on my list to buy because I thought I read that they are an awesome tree for taking extra water way way down with its roots and bringing it back up when other plants need it - when there is a drought. Is there another tree that does that or is it the Mesquite. I thought that it was something I had read about on Neal Spackman's blog.

Help me! I'm really confused about it now

Sheri

Sheri Menelli wrote:Mesquite Trees - after glancing at the discussion about Mesquite trees - I'm confused. I had it on my list to buy because I thought I read that they are an awesome tree for taking extra water way way down with its roots and bringing it back up when other plants need it - when there is a drought. Is there another tree that does that or is it the Mesquite. I thought that it was something I had read about on Neal Spackman's blog.

Help me! I'm really confused about it now

Sheri

I found it - here is something about Mesquite and how it redistributes water during drought by bringing it down deep into the ground until it is needed. Maybe I read this in a Brad Lancaster book as the experiment was in Tucson?
http://onlinelibrary.wiley.com/store/10.1029/2007WR006149/asset/wrcr11390.pdf;jsessionid=11823AF25B987D311A40457ACD36DCF8.f01t01?v=1&t=i7mn3t7y&s=22b08ed3ba5f6d40e048811a795b0ac8ad6c000b

Sheri Menelli wrote:

Sheri Menelli wrote:Mesquite Trees - after glancing at the discussion about Mesquite trees - I'm confused. I had it on my list to buy because I thought I read that they are an awesome tree for taking extra water way way down with its roots and bringing it back up when other plants need it - when there is a drought. Is there another tree that does that or is it the Mesquite. I thought that it was something I had read about on Neal Spackman's blog.

Help me! I'm really confused about it now

Sheri

I found it - here is something about Mesquite and how it redistributes water during drought by bringing it down deep into the ground until it is needed. Maybe I read this in a Brad Lancaster book as the experiment was in Tucson?
http://onlinelibrary.wiley.com/store/10.1029/2007WR006149/asset/wrcr11390.pdf;jsessionid=11823AF25B987D311A40457ACD36DCF8.f01t01?v=1&t=i7mn3t7y&s=22b08ed3ba5f6d40e048811a795b0ac8ad6c000b

Hi Sherri,

Prosopis species are one of those proven to do hydraulic redistribution. I did write about them on my blog post at twovisions. However, while it's been shown that they can do this, i'm not 100% sure about the actual mechanism. However, my understanding is much more in line with Devon's--I don't know if anyone can point to an example in which Mesquites drained an aquifer, but I know I can grow them on very little water, and they're producing pods and honey for me.

Neal Spackman wrote:

Sheri Menelli wrote:

Sheri Menelli wrote:Mesquite Trees - after glancing at the discussion about Mesquite trees - I'm confused. I had it on my list to buy because I thought I read that they are an awesome tree for taking extra water way way down with its roots and bringing it back up when other plants need it - when there is a drought. Is there another tree that does that or is it the Mesquite. I thought that it was something I had read about on Neal Spackman's blog.

Help me! I'm really confused about it now

Sheri

I found it - here is something about Mesquite and how it redistributes water during drought by bringing it down deep into the ground until it is needed. Maybe I read this in a Brad Lancaster book as the experiment was in Tucson?
http://onlinelibrary.wiley.com/store/10.1029/2007WR006149/asset/wrcr11390.pdf;jsessionid=11823AF25B987D311A40457ACD36DCF8.f01t01?v=1&t=i7mn3t7y&s=22b08ed3ba5f6d40e048811a795b0ac8ad6c000b

Hi Sherri,

Prosopis species are one of those proven to do hydraulic redistribution. I did write about them on my blog post at twovisions. However, while it's been shown that they can do this, i'm not 100% sure about the actual mechanism. However, my understanding is much more in line with Devon's--I don't know if anyone can point to an example in which Mesquites drained an aquifer, but I know I can grow them on very little water, and they're producing pods and honey for me.

Thanks Neal. I'm really enjoying (and addicted to ) your posts, blogs and videos. You are doing great work - very exciting. I'm looking forward to more updates as you learn and do more.
Sorry I wasn't able to meet you in person this time at the Permaculture Voices Conference. I was there last year but was unable to make it this year.

Sheri

Hello I live in central Missouri . According to USDA prosopis  glandulosa is native here but I’ve had no luck with the California or Texas origin seeds I’ve grown surviving the first winter.  Does anybody here live or know a nursery that may have mesquite prosopis glandulosa  in the northeast of its range? I’m talking kansas, Arkansas, Missouri, and eastern Oklahoma. Thank you!