Is that Ficus benjamina?

No idea. They have many slender trunks.

Any thoughts on this? How much water do these need? I'm in SoCal and it's been extremely hot and dry. I hand water 2-3x per week with a hose.

there arent many thoughts.. because we cant ID the tree .. better pix ...

IMHO ... mature trees as such.. do not need to be watered ... they should.. at that size.. and age.. be able to fend for themselves ...

and the pic is not good enough.. to make any further guesses ...

is the pool new??? ... maybe reflected sun is cooking them... in other words.. you changed its growing conditions ...

ken

With multiple stems they are likely F. benjamina, and their roots will destroy the masonry walls eventually. These trees have enormous root systems. Keep them short and trimmed back in order to protect your masonry. They get planted in CA because they are fast and cheap. Their aggressive surface roots are huge and buckle pavement and walls. Keeping them clipped into a narrow hedge will hold off damage to your walls--for a while.

See if that one is getting less water than the others. Have a look at the root systems--it might scare you.

Here is a link that might be useful: USFS fact sheet on F. benjamina

Hi all,

Thanks for the advice so far. Here are some better pictures. In this post you can see the trunks of the tree.

I'm aware of the root system issues with Ficus. Luckily, this isn't my house -- I rent. My main concern is keeping the trees alive for their own benefit, so they provide privacy, and so my landlord does not complain that I killed the trees.

This photo shows the state of the trees currently.

And again, some of them look really lush and full. There are about 14 trunk-bundles in that planter.

Reflection off the pool is a possibility. These started looking bad in late spring, when sun intensity would be greatest off the pool. That said, we did keep the pool covered with blue plastic when we were not using it (though it's been uncovered all the time for about 2 months). The pool has been there for many years as I understand it. I don't know how old the trees are.

Talk to the landlord for advice what to do, or not.

Perhaps an onsite evaluation by a Certified Arborist or two.

I know they shed leaves and put on new even indoors, so it may just be doing that. I used to have one indoors. They may need extra water, my potted one liked plenty of moisture. I would still have it, but we have cats, nice and curious cats, so you know how that goes, no houseplants are safe for long.

If they die, print out some web pages on what their root systems do to masonry, give them to your landlord and tell him he's lucky.

It could be the ones that are doing well have found their way into more soil and water in the neighboring property, or else they are sucking up resources at the expense of the ones doing poorly. You could try watering more, that's about all you can do.