Tree struggles while it's neighbors thrive

[savtrack]

Thanks in advance to any who can assist with this...

I'm located in Southern California and have 3 trees along my side yard- 2 are thriving while the other tree struggles. I'll post pictures below, but here are the basics... all 3 are the same kind of tree. The 2 smaller ones are kicking butt at the moment, while the larger tree struggles.

All get roughly the same amount of water from my drip system (though the large one does get a bit of overspray from the nearby lawn). I've tested soil softness-the soil hardness seems to be consistent in a 24" radius around all 3 trees, so I don't think the big guy isn't getting enough water.

The fejioa tree right next to the struggling tree is also flourishing...

Any opinions on what's wrong and any suggestions on how to fix things?

The side yard
http://farm4.static.flickr.com/3001/2639484317_9124715f3d.jpg?v=0

Happy tree #1
http://farm4.static.flickr.com/3114/2640311630_276b2e76d5.jpg?v=0

Happy tree #2
http://farm4.static.flickr.com/3073/2639484813_4edb731f99.jpg?v=0

Thriving fejioa + struggling tree
http://farm4.static.flickr.com/3113/2640312208_cbbba1fbb8.jpg?v=0

Struggling tree
http://farm4.static.flickr.com/3089/2640312642_4d52ae1815.jpg?v=0

[NCSULandscaper]

because its a larger tree, its a better chance that it can go through transplant shock, even if its in a container or B&B

[savtrack]

because its a larger tree, its a better chance that it can go through transplant shock, even if its in a container or B&B
These trees went into the ground over a year ago.... would transplant shock still be an issue? The tree in question has been going backwards for about the last 6 months or so....

[Mau]

What kind of drip system are you using? Is it a Netafim-type or separate emitters plugged into the supply line? If it's emitters, how many do you have per tree?

I would dig down and see what the moisture levels are like 24" down.

Is this a new planting - meaning has there been anything planted there before? If it is new construction there may have been something poured in that spot. Painters could have washed out their brushes there or the hard scape guys could have washed their tools there raising our already high soil pH even higher.

What kind of trees are they?

[Mau]

Another question. What size were these? Was the larger one a 24" box and the smaller ones 15 gal.?

[savtrack]

What kind of drip system are you using? Is it a Netafim-type or separate emitters plugged into the supply line? If it's emitters, how many do you have per tree?
Separate emitters into a supply line- 2 emitters/tree

I would dig down and see what the moisture levels are like 24" down.
I planted the fejioa tree about 4 months ago and had planned ahead and installed the emitters for it about a week in advance of digging the hole. The soil was moist all the way down to about 30" when I dug the hole, so I'm assuming that a similar setup should be giving me similar results with this tree.
Is this a new planting - meaning has there been anything planted there before? If it is new construction there may have been something poured in that spot. Painters could have washed out their brushes there or the hard scape guys could have washed their tools there raising our already high soil pH even higher.
New planting/new construction. I dug the holes for all of the landscaping and didn't notice anything while digging..... no concrete obstructions or any 'white washed' areas where it looked like the drywallers or painters had cleaned up.

What kind of trees are they?
I can't believe I'm saying this, but I can't remember. I keep wanting to say Bottle Trees for some reason, but everytime I do a google image search for them I get something that doesn't resemble them at all.

[savtrack]

Another question. What size were these? Was the larger one a 24" box and the smaller ones 15 gal.?
Exactly.

[Mau]

It sounds like your soil moisture is OK but that is the first thing I would question. Without seeing it in person, I would guess the larger tree isn't getting enough water.

A 24" box is going to need quite a bit of water - more than the 15 gal. trees. Maybe you are watering enough for the smaller ones but not enough for the big one. Perhaps the larger tree needs 3 or 4 emitters rather than 2. Ideally, I would have circled the trees with the supply line so you would assure good water distribution all the way around - with more than 2 emitters.

How often and how long is the drip zone running? What size emitters are they?

I would probably be giving it a good drink every 10 days or so. 'Good drink' being 10 to 15 gal. of water. If you had a basin built up it would be easier to apply.

You can make a moisture checker with a skinny bamboo stake. Plunge it into the rootball of the 24" box tree. Pull it 24 hours later and see if the stake is moist. Keep using the same hole until you get a handle on how much water is needed to keep it moist.

Conversely, how's the drainage there? Did you happen to do a perc test when you dug your holes - fill the hole, let it drain, fill it again and time how long it takes to drain?

[savtrack]

It sounds like your soil moisture is OK but that is the first thing I would question. Without seeing it in person, I would guess the larger tree isn't getting enough water.

A 24" box is going to need quite a bit of water - more than the 15 gal. trees. Maybe you are watering enough for the smaller ones but not enough for the big one. Perhaps the larger tree needs 3 or 4 emitters rather than 2. Ideally, I would have circled the trees with the supply line so you would assure good water distribution all the way around - with more than 2 emitters.

How often and how long is the drip zone running? What size emitters are they?

I would probably be giving it a good drink every 10 days or so. 'Good drink' being 10 to 15 gal. of water. If you had a basin built up it would be easier to apply.

You can make a moisture checker with a skinny bamboo stake. Plunge it into the rootball of the 24" box tree. Pull it 24 hours later and see if the stake is moist. Keep using the same hole until you get a handle on how much water is needed to keep it moist.

Conversely, how's the drainage there? Did you happen to do a perc test when you dug your holes - fill the hole, let it drain, fill it again and time how long it takes to drain?

Thanks for the advice- I was afraid that maybe it was getting too much water (from the lawn overspray) and/or the drainage wasn't good enough and that I was slowly drowning the tree. I'll pick up a bamboo stake tomorrow and see how it looks after a 24 stretch down there.

Thanks so much- I'm obviously stumped and everything else in the yard is growing like crazy.... I'll check with the bamboo stake and report back and then decide where to go from there.