Any one of the first 4 could be pruned into a small tree or tree-like shrub - start EARLY and prune lightly and frequently to lift the canopy and

Also look into Texas Olive (Cordia boissifolia) for a well-behaved small tree.

If you want the plant to benefit from the shade, plant it on the east side, no more than 30% of the height of the shade-giving plant away from the base.

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I have no experience with the others, sorry.

Thanks for your expert advice, lazygardens. Just the kind of information I can use. Much appreciated.

I like the rule of thumb for placing shade-giving plants. I'm going to assume I could even shift shade-giving plant a little more to the SE if shade-receiving plants have uninterrupted S & W exposure during most of the year.

To be perfectly clear, if a plant is estimated to grow to 10' tall, I would leave 3' between the bases of the plants?

Again, thanks for the guidance in placement and pruning of plants.

Lazygardens,

One more thing...

Went to three sites with descriptive info on Texas Olive (Cordia boissifolia):
First said 10'x10'.
Second said 10-20' with equal spread.
Third said 10-25' with equal spread.
Averaging these three estimated heights = ~14'.

Since the rule is "no more" than 30% of the height, maybe it's safest to go with minimum extimated height?

"...if a plant is estimated to grow to 10'....bases of the plants?"
Are you wanting to grow a hedge? Or is 3' how far you wish to plant the shade-lovers from the shade givers? I'm confused.
When planting under trees keep one word in mind-roots.
Also be mindful of the water competition issues.

Have you considered Leucophyllums? I don't know how they'd do in your area but they can take the desert that's for sure.

Hello, New Mexico Girl

Lazygardens said

If you want the plant to benefit from the shade, plant it on the east side, no more than 30% of the height of the shade-giving plant away from the base.

Thank you. You made me realize I was totally misinterpreting her instructions.

Now my read on it is that if you have an 8' tall bush with an equal spread, you would leave 2.4' between the expected full size of both plants. At least this would take into account the root/water competition issue.

Do you have a different interpretation?

I have considered Leucophyllums, pomegranate tree, wolfberry (Lycium) varieties. Can't decide urban landscape vs. hiking trail landscape.

Thanks again for making me rethink the plant placement.

Texas Olive ... the ones I have seen in Arizona are trimmed up to be patio trees. They are mature and about 10-15 feet high with about a 10 foot span for the canopy. Nice dense dark green with lovely huge white crepe papery flowers.

There's a church near here that has three of them shading the south side of one building.

On the relationship between the "nurse plant" and the shade-loving plants:
1- Let the nurse plant get big enough to cast some meaningful shade first. That sapling mesquite isn't going to be useful for a few years. You might have to use a temporary shade structure unless you can wait for the nurse plant to grow.

2 - Look at where the shade is in the heat of the day, and plant the shade-lovers there. If you have to guess, for the purposes of drawing up a plan or to make sure you have enough room, you will get adequate mid-day shade in the inside 2/3 of the canopy cover. Earlier and later you will get slanting light that reaches farther under the canopy.

Plants on the east side of the nurse plant will get longer shade in the afternoon, plants on the north side can get a surprising amount of morning and afternoon sun.

As the nurse plant grows, the fully shaded area gets larger, of course.