FWSB is drought tolerant, so it shouldn't be a problem. NOTE - FWSB needs full sun.

Thanks for your response, petzold. What I am thinking about is that being draught tolerant is not necessarily exclusive of water hogging, when the situation presents itself. Thus, my worry that salt bush is usurping water from some of my trees.

FWSB is prevalent on my property, seeds itself readily and grows rapidly. New bushes have established themselves near my old catalpa tree. I let the bushes be. I gave the tree extra water because of the long period of harsh winds this year. The tree didn't fully leaf out this year. Perhaps I didn't give the tree enough extra water, perhaps salt bush is hogging the water, or maybe the tree is nearing the end of its life span.

A few years ago I saw a PBS special on restoring natural desert springs. The focus of the restoration project was to remove salt bush. I don't recall whether it was a specific type of salt bush. They said salt bush seeds had been carried in the coats of cattle during cattle drives and widely disbursed to areas where it wasn't native. Wherever salt bush established itself in these new areas, natural springs dried up. The salt bush was taking in as much water as it could get, to the point of drying up springs. Within a few months natural springs began to reappear where the salt bush had been removed.

Lorna

Lorna,
It's been my experience that if the water is there, FWSB will take it. They're easy enough to relocate when they're small and, as you know, more will sprout up. I don't know what's wrong with your tree but I'd remove the salt bushes. As Petzold said, they like full sun anyway.
Vanessa

I believe the PBS special referred to Tamarix (Tamarisk) species, also called 'salt cedar' rather than salt bush as a means of restoring desert springs. FWSB has much shallower root system than Tamarix. The state of NM has spent a great deal of money eradicating salt cedar in Central and Northern NM riparian areas in recent years. I would probably remove the FWSB anyway, since they are so abundant and will compete for water.

Thanks for the responses/advice. Desertlvr, you are correct. You have jogged my memory, the PBS show was about salt cedar removal.

Next question, how does one remove a large FWSB? I find I cannot pull them up by the roots, once they have begun to branch out. FWSB does have a significant tap root. Would sawing large bushes off at the base kill them? Lately it seems that my hand saw is gaining prominence as an oft used garden tool!
Lorna

My hand saw has become increasingly important, too. I would cut them off close to the ground. Eventually the roots should die. At least, that is a nontoxic approach to take. If the monsoons kick in this year, you might be able to pull up the root ball if the soil gets wet enough.
Good luck. dl