would you know how hard or easy to root a cutting of a ocotillo
Sure! Doing so is not a difficult process, but take extra cuttings. They tend to be pretty unreliable at rooting. Some will and some won't root, so taking extra cuttings will ensure that you get, at least, one.
Here are some articles that will help:
https://www.gardeningknowhow.com/ornamental/cacti-succulents/ocotillo/ocotillo-plant.htm
https://www.gardeningknowhow.com/garden-how-to/propagation/cuttings/root-stimulating-hormone.htm
We have many Ocotillos on the property that are beginning to get leaves but the one that has very few leaves on multiple stems has many stems that are silver on color. Are those stems dead? Should we remove them?
Unfortunately, your photo did not come through. It does sound like you have a few that are dying on you, though. It would be a good idea to cut off any growth that is completely dead, and treat with an insecticide, since this will be the most common cause of any issues with this plant.
Here are some articles that will help:
https://www.gardeningknowhow.com/ornamental/cacti-succulents/ocotillo/ocotillo-plant.htm
https://www.gardeningknowhow.com/special/organic/what-are-organic-pesticides.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides
This plant was started from seed in Tucson, I’ve had it home about 3 months. Leaves were green till this week. We did have rain. I water it 2 times a week on a schedule.
Likely, it has received too much water. Instead of watering on schedule, make sure to water only when it is needed. A water meter may be necessary to get a reading deeper into the container.
Here is an article that will help you to use one:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-moisture-i
Unfortunately, your photos did not come through, so I am unable to see the damage. I can provide a link to an article that will help you to grow one of these to their potential:
https://www.gardeningknowhow.com/ornamental/cacti-succulents/ocotillo/ocotillo-plant.htm
I have two ocotillos that green up some years and produce flowers from time to time, however the have not developed any new canes at the base in the last nine year since planting. They are pretty much the same size as when I bought them.
If they aren't growing, it may be a soil issue. These articles should help:
https://www.gardeningknowhow.com/ornamental/cacti-succulents/ocotillo/ocotillo-not-blooming.htm
https://www.gardeningknowhow.com/ornamental/cacti-succulents/ocotillo/ocotillo-plant.htm
how do I treat it? I'm not sure if I need to treat with insecticidal soap, leave it be, or even trim it off. Thank you in advance!
It looks like the new growth above it is normal so consider leaving it for now. The black leaves will probably fall off. If the whole cane dies you can remove it. (You could cut it back to clean wood, but then it will branch out, ruining its look.)
Make sure the plant is not getting too much water. Here is more on how to care for ocotillo:
https://www.gardeningknowhow.com/ornamental/cacti-succulents/ocotillo/ocotillo-plant.htm
I have a rather large ocotillo that was transplanted into my yard from a construction site. It was alive when transplanted, and was placed 10-15 feet away from another live ocotillo. It has not sprouted any leaves, so I'm wondering if it is dead with no hope of coming back to life.
I would give it more time. It may be establishing its root system rather than growing leaves. The article below says it can take 6 to 12 months to establish and start growing leaves. Continue to water it until it starts leafing out, then you can let rain do the watering.
https://www.gardeningknowhow.com/ornamental/cacti-succulents/ocotillo/ocotillo-plant.htm
I have a rather tall, 8 to 10 foot, Ocotillo that has fallen over. Is there a way to save it and also, is there a way to prune it so it isn't so tall?
You can secure the base of the plant with rocks, and you can reduce its size by trimming the wands. If you'd like, you can then set the wands in soil and grow new plants.
https://www.gardeningknowhow.com/ornamental/cacti-succulents/ocotillo/ocotillo-plant.htm