Stress.

Dan

Pistache are changing color in northern California, as well.
Some are yellowing, others are half-red at this point. Trees / leaves
with a western exposure turn color sooner.

Josh

Well, August is summer here, & even September is still summer in Texas;
the gardens (& gardeners!) have already been subjected to long stretches of heat & dry weather.

We don't get cooler daytime temps until mid- to late October, & it usually doesn't feel like autumn until November!

Unless you've been deliberately trying to drown those trees, I don't think it's over-watering;
I'd guess it's summer dormancy caused by heat/drought stress.

Bald cypresses, for instance, turn brown & lose needles during August & September almost every year, & then they grow green needles again before they go into winter dormancy in December.

Fall color in Dallas area do not start until November. Chinese Pistache is known for its toughness so there must be something else. It should be able to tolerate drought and heat just fine otherwise it wouldn't be on Texas Superstar plant list.

I have a few questions...

How big is the tree when you plant it? Did you make sure to expose root flare at the ground level? Often times people plant trees too deep.

Did you provide generous mulching? How wide? How thick? Anything touching the trunk?

What was your watering practice like for your tree?

Do you happen to have clay soil?

Like sylviatexas & lou_midlothian_tx mentioned temps are still in upper 90 here in Tx way too early for Fall.
To answer some of your question lou_midlothian_tx.. The trees were planted in Oct 07 by the builder when we moved in. They were about 10-12 feet tall. I am sure they plopped the tree in the ground with very less care. But last summer they were just fine. They even had beautiful red foliage in fall. I think, I have been mulching them fine. About 2 ft around and 4-6 inches thick. The mulch sure is touching the trunck. This might be one thing I should fix.
As for the watering.. there is a irrigating cycle specifically for the trees. I think I water them about 20 minutes every 4th or 5th day. Also there is the runnoff from a flower bed that I water almost daily. This is why I fell I might be watering them too much.
Based on the replys so far it looks like the yellowing is not normal and the tress are not happy. I think I need to look at them more carefully.. See for disease/pest problems. Dig around the tress to see if the soil is too dry/wet.Anything else you can think of? Maybe I should take a picture and get all yours wonderful advice. They are just beautiful tress and I dont want to lose them. Thanks

The watering really does sound like a potential problem. Daily doses of water with lots more water every 4th or 5th day sounds like WAY TOO MUCH water.

I suspect from the size of the tree it was B&B and that means a good possibility planted too deep. Maybe too much water is a contributing factor but without pix I'd guess too deep and stressing because collar is buried.

Dan

Temps are in the 90°F's here, too.
(Not that I'm suggesting California and Texas weather are the same! Lord knows they aren't!). I've kept my eyes peeled the past few days and I've noticed quite a few Pistache beginning to change color.

Has the weather in Texas been exactly the same this year as in years past?

Josh

Blue Chip,

You definitely need to pull mulch back from the trunk.

Are you still using that tree bubbler that's placed by the trunk? I don't think it's that effective now since the roots probably have spread out by now. I would have just used watering bag and be done with it after a year and use soaker hose around dripline. I honestly think tree bubblers are nightmare. How do you get rid of it? It is useless after 1-3 years depending on the size of the tree.

I'm surprised that no one has mentioned this yet, but it is highly likely that the cause of premature yellowing of the leaves on your Chinese pistache tree is because of a magnesium deficiency. This happens when the pH of the soil is too low. PIstache trees do not grow well in soil that is too acidic. The solution is rather simple, though. Dissolve 4 tablespoons of Epsom Salt in a quart-sized container of water and pour it on the base of the tree once every 2-3 weeks. The yellowness will disappear and your leaves will turn green. By the way, I live in CA where the summers are hot and very dry.

My Chinese Pistash is doing the same thing! We just turned on the sprinklers and the water is hitting the tree right in the area where all of the leaves are turning yellow and scorching in the sun. So now do we adjust the the lawn sprinklers or switch to watering after sunset?

I have four mature Chinese Pistache trees which are about 8 years old. One has been dropping all of its leaves after turning yellow. It's the only female tree and the other three only had a few leaves turn yellow. This started after much rain we had in late Spring here in the Dallas area. The one which is in bad condition was sitting in pools of rain water often and the other three were on high ground although near by. I am beginning to believe the problem is about the water. I am afraid to water them. Is it possible that it is the problem. I have read that some North Texas residents don't water their Pistache at all.

No other trees on my property have this problem. I do not see insects on the leaves but we do have some grasshoppers out here munching on things a bit but that is only recently and long since the yellow leaves began to drop. I am just curious if other North Texas residents are having this problem. If so, then perhaps the excessive water in late April and early May could be a widespread cause of this issue and affecting only or mostly this type of tree. And if so, then what is a good solution to save the tree. Any comments?

you might be best off.. starting your own post.. adding the TX forums.. if any ... and adding pix of your trees

you might also want to talk with your COUNTY extension office for more local advice ...

ken

I have two that are turning yellow as well. Any solution? I'm in North

@Monte Thompson I live in North Texas as well and having the same issue w female who looks to have been overwatered. I had x2 Chinese Pistache (M/F) recently added to my front yard in April. In the beginning, the Male was yellowing a bit struggling to bloom out in the season. I thought it was possibly that it was timing of planting, as the male had started the leaf on install but female had none. The female later took off on a normal watering schedule of every 3 days for about 10 minutes each with a direct water hose, while the male was slow to get going. I started watering the male more, which in turn caused me to start watering the female more without thinking about it. By the time he was catching up blooming out more leaves, the female whom was rock steady since blooming, turned to yellow completely overnight. I realized I was possibly overwatering, As on install they put in a drain pipe to check the moisture levels of the trees, and ensure not to water them if they test stick would bring up mud w excessive moisture. I was informed that it should be close to playdough with some moisture but not wet/muddy as this could lead to issues. I checked those drains and the female was wet/muddy as the male was not. So my drainage on that tree definitely needs to be reassessed or I definitely be more mindful not to overwater. Either way I believe the tree is still alive, as they are extremely hardy trees, I am told. I assume it will go thru losing its leaves, fall winter cycle and only fully recover to next Spring cycle. Time will tell as I am not certain anything can be done, beyond dramatically reduced water and checking the drain for soil samples keeping the moisture consistency to playdough levels. Attached are pictures of female tree healthy, then the tree one after turning, day three after, and current 2.5 weeks later. I had searched the Internet for information but found very little, so I hope this helps someone as it freaked me out, but later realized I was not monitoring the drain moisture consistency and simply overwatered.

Abercan and Scott Lewis. My female Pistache has now been given plenty of fertilizer and less water which has helped. I aerated the soil around it. It did not die, the leaves stopped turning yellow and dropping and looks almost like the other Pistache trees on my property. There is a shopping area in Fort Worth with dozens of Pistache trees and many of the them had the same appearance starting in early Summer like mine. They are looking better as well and turning Fall colors and dropping as they should. The only difference I have noticed is that none I have seen are as orange as they should be. My research indicates that my suspension of too much rain pooling around the tree after our unusual freeze in February certainly could be the cause of previous problems. I had one Pistache tree that lasted for over twenty years and died after a severe freeze then very wet Spring.

@Monte Thompson thanks for the quick reply and I am very glad to hear your tree bounced back. I am curious did the whole entire tree change color, similar to mine, then bounce back to green or simply stop losing leaves? As mine I would assume would not continue to grow much as we enter Fall. The leaves have not really fallen since the tree colors have been changing, which I assume is a good sign. Can you share the types/amount of fertilizer you used? Also how long before you saw results of it coming back, as your initial post was 2 months ago. If possible could you share photos of the female you had issues, TIA!

I will take photos tomorrow of the trees and post them. I have had pistache trees on my property for many years and they always stay green full Spring and Summer. The one female that is about seven years old had its leaves turn yellow in June and dropped a lot of them and the green berries turned brown. After aerating and putting in a lot of fertilizer spikes the leaves stopped turning yellow and the green leaves that were left have stayed green and are only turning yellow a bit today. The other pistache trees are very healthy and are dropping yellow and gold leaves right now which is usual for this time of year. The berries on the healthy females should have turned orange but they didn't.

I don't remember what the fertilizer spikes were. Understand that my soil may be different than yours because I'm West of Fort Worth on what had been a dairy farm. Right now, typically, a pistache tree should have some healthy green leaves with bright yellow leaves with bright orange areas. Berries would be turning red.

If you bought your trees from a good nursery they may be guaranteed for replacement. I get mine at Calloways and keep the receipt. Because yours was planted in April it still could have been damaged by the freeze in February depending on where the nursery was.

I have hundreds of trees on my property and so do my neighbors. Many other trees were having issues this summer with some neighbors needing tree surgeons to come out. They were told that the problem was mostly because of the February freeze. The native oaks did well but more ornamental trees were stressed,

Excellent, thanks again for the update. Thankfully I did purchase and have TreeLand Nursery install the trees. They do have a 1 year warranty, and I have been in touch with them to keep them updated, if I may need a replacement. Hopefully not, but time will tell. Thanks again for your insightful help, take care!

Tree is defintely a goner, so sad.

Odd root wrapping around the base, could this be the issue? My gardener originally stated that it would grow and choke out the tree as it wraps around the base oddly.

Maybe he was right, as he stated that right after install 5-6 months before tree died. Also final note, the male Chinese Pistache was on same watering cycle is doing fine and well transplanted 30 feet away from the other tree.

Chinese Pistache is becoming very invasive in the southeast. I wouldn't recommend growing them, and if you have them you may want to destroy them. They should be banned from sale. This is current information from Alan Weakley and all southeastern botanists.

Jay- Wondering how/why they would be considered invasive? Here in Silicon Valley they are street trees, many over 60 years old. Beautiful Fall color and small leaves that are easy to rake. Turning red/orange/yellow right now in San Jose.

-Babka

Babka, they are definitely invasive in the Southeastern U.S. Reports of it's spreading in North Carolina, and Louisiana.