Thursday, September 10, 2009

Iconic Desert Tree, The Palo Verde

Blue Palo Verde in Flower

 When people think of the Sonoran Desert, hillsides studded with Saguaro cactus and cholla often come to mind.   But interspersed between the cactus, you will find the beautiful Palo Verde trees.  Their unique green trunks are perhaps their most notable feature. 
The word "Palo Verde" means "green stick" in Spanish, referring to their green trunk, which is actually a survival mechanism in response to drought.  Palo Verde trees are "drought deciduous", which means that they will drop their leaves in response to a drought situation.  Their green trunks and branches are able to carry on photosynthesis, even in the absence of leaves. 
'Desert Museum' Palo Verde

 Palo Verde trees act as a "nurse plant" to young Saguaro cacti by protecting them from the cold in the winter and from the intense sun in the summer.  Beautiful, yellow flowers are produced in the spring.    
  'Desert Museum' Flower

 Two species of Palo Verde are native to the Desert Southwest; Blue Palo Verde (Parkinsonia florida), formerly (Cercidium floridum) and Foothill Palo Verde (Parkinsonia microphylla), formerly (Cercidium microphyllum).  Two other species of Palo Verde that are prevalent in the landscape are the Palo Brea (Parkinsonia praecox), formerly (Cercidium praecox) and a hybrid known as (Parkinsonia x 'Desert Museum').  Their cold hardiness range is around 15 to 20 degrees F.

Palo Brea

 PALO VERDE USES: Palo Verdes serve as wonderful specimen trees where their green trunks, branch structure and flowers are a wonderful focal point.  They are drought tolerant, once established.  They provide nice filtered shade year-round.  When deciding where to place, be sure to take into account that they need a lot of room to grow, mature sizes are listed below.  Palo Verdes do not do well when planted in grass and will decline over time.  Locate away from swimming pools due to flower litter in the spring.
Because of their larger thorns and branching tendency to point downwards, Palo Breas are not recommended in areas close to foot traffic.  
Mature Sizes:
Blue Palo Verde - 30 ft x 30 ft
'Desert Museum' Palo Verde - 30 ft high x 40 ft wide
Palo Brea - 30 ft x 25 ft
Foothills Palo Verde - 20 ft x 20 ft
As with many desert trees, Palo Verde trees have thorns, except for the 'Desert Museum' Palo Verde.  

Foothills Palo Verde

  PALO VERDE MAINTENANCE:  Prune to elevate the canopy and maintain good structure.  Avoid hedging and "topping" trees as this stimulates excess, weak growth.
MY FAVORITE: As a landscape manager, horticulturist and arborist, I have grown and maintained all of the Palo Verde species mentioned and I truly enjoy them all.  However, at home I have 4 'Desert Museum' Palo Verde trees.  In comparison to the other species, their trunks are a deeper green, they produce larger flowers, they are thornless and grow very quickly.  In addition, they require little, if any, tree staking when planted. 

Palo Brea in Flower

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Tatyana@MySecretGarden said...

Yes, I think I also would prefer the thornless one! Thanks to you, I will know more Phoenix trees' names when go there to visit my relatives.

azplantlady said...

Hi Tatyana. Me too! I used to have a Palo Brea and it was very beautiful, but is sure did get some scratches from the thorns when I was not being careful.

Thank you for the comment!

Barbara said...

Hello! I came across your page while looking for information on how to care for our Palo Verde tree. You mention that pruning is important. Can you please advise on when the best time of year for pruning would be, and how much we should take off? Any input is greatly appreciated!

Noelle said...

Hello Barbara,

Thank you so much for your comment. Palo Verde trees are best pruned in June, once they have finished flowering. As a rule, you should not remove more than 20% of a tree's branches a year. To do so, would put undo stress on the tree, leaving it susceptible to disease and other stresses.

I hope this helps!


Barbara said...

Hi Noelle! Thanks for replying. I was hoping to do it during the cooler months but we'll just have to get up really early one morning in June and beat the heat. Thank you for the good info!
Best regards and happy holidays!

John & Mary in North PHX said...

Hi Noelle, thank you for this great site! We planted a Desert Museum Palo Verde 8 mos ago. and it's now approx. 12 ft tall and 9 ft wide. A neighbor recently suggested we consider "topping off" the tree if we'd like it to grow a thicker trunk. What are the pros and cons of topping off a Desert Museum Palo Verde? Thanks, John & Mary

Noelle said...

Hello John and Mary,

I am so glad to hear that you have a beautiful Desert Museum Palo Verde. You will enjoy its beauty for years to come. I just love mine:-)

Okay....whatever you do, DO NOT top your Palo Verde tree or any tree for that matter. There are honestly no pros for topping trees. I do have plenty of cons though. First of all, topping DOES NOT lead to a thicker tree trunk. Furthermore, it stresses the tree by removing foliage that it has to work hard to replace, it leaves the upper branches open to sunburn, 'topping' actually causes your tree to grow back faster and the new branches have a weak attachement which can cause them to break off easily...there are many more reasons not to top and you can find them at the following link

I hope this helps :-)

Anonymous said...

3rd time's the charm!
I have a DMPV in a bed with an almost-native grass meadow, a mix of blue grama & curly mesquite. If it's not irrigated will it be OK together?

Kimberlyn Drew

Noelle said...

Hi Kimberlyn,

If your tree is newly planted in that area, it will need irrigation until it becomes established, which can take 1 - 2 years. Thereafter, it should be okay as long as you water it deeply 3 - 4 times during the summer.

Good Luck :-)


Anonymous said...

Thanks Noelle,

I was referring to your comment that PVs will decline if planted with grass. Is my combination OK? Both are pretty well established. The tree is at least 3 years old and doing well, and the area is primarily watered by rainwater runoff from the roof (passive rainwater capture system).

Thanks again,
(My first two comments had been more detailed, but it took me three times to get it to stick so I made the final message overly brief.)

Noelle said...

Hello Again Kimberlyn,

The problem with Palo Verde trees grown in grass is largely due to the use of sprinklers. The water leaves salt deposits behind on the trunks, which can affect the photosynthesis rate. So, you should be fine since you don't use sprinklers. I think you are in good shape :-)


Unknown said...

Noelle, I have a newly planted small size "museum" palo verde. We planted it in early Feb. We have been watering it once or more a week until it is established, but now the leaves are going yellow, & we think it's gotten too much water. Do you have any suggestions for me? I didn't water it at all this week, do we need to give it some nutrition or just back off and stop watering? Thanks so much, Amy

Noelle said...

Hi Amy,

I think you are right that it has gotten too much water. RIght now, you are doing the best thing by not watering it and letting the soil dry out. Don't add any fertilizer - that will stress your tree even more because it will stimulate to work hard to produce leaves when its roots aren't large enough to support them.

You won't need to fertilize your Palo Verde tree at all through its life. They are used to growing in our soils. For its first year, I would water it deeply (3 ft) every 10 days until November, when you can then back off to once every 15 - 20 days.

I hope this helps.


Tina J. O'Keefe said...

Hello! So glad I found this blog. I planted 2 DMPV trees about 18 months ago, and they haven't grown at all!:( They are blooming right now, but not a lot of blooms. I hardly water them, they got a lot of rain water this past winter, and I now water them about every other week. I live in Southern California. Not sure if I am doing something that is stunting their growth? Any ideas? Thanks! Tina

Josh deBerge said...

Hi Noelle,
Thanks for this resource! Quick question. I recety planted 3 DMPV 15 gallon trees. I swear the nuresry told me to give the tree a long watering that floods the 3 foot diameter little 'catch basin' on a daily basis.its day two and it seems a bit excessive. I already have a bit of yellowing on a few of the trees, but i assumed that was from a bit of shock from transplanting. How often, how long, and how much should i be watering them? Thanks.


Noelle said...

Hi Josh,

I am so glad you are growing Desert Museum Palo Verde trees. They are by far, my favorite desert tree.

The nursery was correct in advising you to water your tree daily - I would do this for the first 4 days. Then you can gradually taper off to every other day for the next 4 days. Then you can go to 3 times a week.

I suspect that the yellowing leaves is a sign of transplant shock. It is always hard when plants are first planted, especially in summer.

Keep a close eye on your tree. You may need to adjust your watering schedule if the soil becomes water-logged.

I hope this is helpful :-)


Arid said...

Hi Noelle! I too am glad I found your blog. I recently bought a vacation home in Lake Havasu City, AZ, and am so excited about the prospect of nurturing a desert garden. At the same token, I'm a little worried I'll destroy what has been established. There's a large PV in the front yard, the focal point of the garden. With infrequent summer visits, I am afraid the tree will die without manual irrigation, yet we haven't had time to establish a timed system. I've soaked the tree basin about once a month so far and as of last week, it looks pretty good. Should I worry?

Noelle said...

Hello 'Arid',

Thank you so much for your question. If your Palo Verde tree is established (over 3 - 4 years old). It will probably do fine with infrequent irrigation.

If you have irrigation on plants that surround your tree - your tree will get some water from that.

However, desert trees need deep, infrequent irrigation. When you water, you want to focus on applying the water where the branches end (where they reach out too). This is where most of the roots are located.

Using a hose on a slow trickle, let it thoroughly soak the area for an hour or so and then move to the next area so that the entire outer circumference of the tree is watered.

Water to a depth of 3 ft. You can test how deeply you are watering by using a piece of rebar and pushing it into the soil after watering to see how deep the water penetrates and if you need to apply more.

I hope this is helpful :-)

Noelle (azplantlady)

Amber Bailey said...

Hello. I live in Scottsdale, AZ I have 3 large desert museums in my yard and they are very healthy. The lower branches are really starting to spread out and getting a little low over my pool and over my driveway. I am going to have them professionally pruned, but it's the beginning of September. I read that you recommend June for pruning. Will they be okay if pruned in early Sept?


Noelle said...

Hello Amber,

Actually, I just had to do the same thing to my new Palo Verde tree. You can prune it a little right now - but try to avoid pruning any more then you have too.

In a given year, you should never prune more then 20% of a tree's branches.

Good Luck!

Carter Madson said...

Thanks for sharing! I recently just planted the first pic of the desert tree in my yard. I love how the trunk and branches are green. It makes it look like there's moss which would give the year the illusion that you don't actually live in a dry desert wasteland ;) I did just mulch my yard, will that hurt the tree?

Noelle said...

Hello Carter,

Too much mulch near the tree can cause problems. An inch of mulch will be fine over the root zone of the tree (the part underneath the tree canopy from the trunk out to the outer branches). Keep mulch at least 6" away from the trunk of the tree or else you can have problems with fungal infections of the trunk.

Good luck!
Noelle / azplantlady

Crimsonidle said...

I feel lucky to have found this page. My wife and I bought a 5 gallon palo verde on Sunday. My goal was to get it in the ground quickly. I planted it, unfortunately at 2 pm it was about 85 degrees. I included miraccle grow soil for trees and shrubs at the bottom and sides as well as with the soil it had in the planter. The hole I dug is roughly 3 ft deep. It was really hard to dig that hole as the ground is really hard here in AZ. I used water to help with the digging so the hole would be moist for planting. We watered that night, Monday and Tuesday at least 5 gallons of water each time. After reading some things on the internet I did not water it last night. The soil appears to still be damp. The leaves are turning yellow now but the yellow flowers are still blooming. We gave it a vitamin mixture in the water on Tuesday.

My question is have we gave it too much water or not enough? Did we make a mistake with the vitamin additive? Is the soil we put it in ok? What can I do to ensure it survives? Please help, my wife will be devastated if we lose this tree. We planted one previously two years ago with no success, but I am certain it is because the dogs peed on it constantly. We are protecting this new tree so that they cannot go near it.

Crimsonidle said...

I feel lucky to have found this page. My wife and I bought a 5 gallon palo verde tree on Sunday. My goal was to get it into the ground quickly so after digging the hole (4 hours) we planted it around 2 pm. It was about 90 degrees that day. The soil was hard to dig, so we also purchased a bag of miracle grow soil for trees and shrubs. We watered it that night, Monday night and Tusday the leaves had turned yellow so I purchased a vitamin mixture for the water and watered it Tuesday night. 5 gallons each night. after reading a few other things on the internet and did not water last night. The ground is still damp about two inches underneath the top soil. The leaves are almost all yellow and it appears as though it may not make it. Which would devistate my wife as she has always wanted a palo verde tree.

Have we over watered? did the vitamin mixture make the shock worse? at this point what can I do to ensure it survives?

Noelle Johnson said...

Hello Crimsonidle,

You have asked some great questions. Palo verde trees are easy to grow, aren't fussy and don't need any special soil or vitamin mixture.

All plants suffer transplant shock when planted. That and/or the condition of the tree when you bought it could be the reason that the leaves turned yellow. The leaves will fall, but should be quickly replaced by the tree.

Trees should be watered to a depth of 2 - 3 feet. Here is a helpful timetable created by experts for watering new desert trees: Every day for the first week, twice a week through June, 2X a month July through October and once a month in winter.

Next year, water 2X a month spring through fall and once a month in winter.

As long as the branches stay green and leaves begin to grow back, your tree should be okay and recover. However, if you notice growing of the branches, then I would recommend starting over.

Good Luck!
Noelle 'azplantlady'


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