Green Giants can certainly grow in a zone 9 - they do so beautifully in mine - but that only measures their tolerance to winter temperatures. It does not address how well they might fair in a hot, arid summer climate.

They would not be my first choice for you. They are not particularly drought tolerant, preferring consistently moist soils. Unless you can provide them with as much water as they need - a difficult task under your watering restrictions - establishment will be slow and rapid growth curbed.

They are also highly flammable, explosively so under dry conditions, which is another significant reason not to plant in SoCal where fire risk is high.

• East Palo Alto is not SoCal....and inland SoCal at that.
• A weekly deep watering is not sufficient to get new trees established, especially in a climate that lacks any significant rainfall for most of the year.
• Not "everything" is flammable and why the state has recommendations for what to plant and how close to any structures or other flammable objects they should be planted. Highly resinous conifers like any kind of thuja should be avoided.
• A plant being sold at Home Depot carries NO guarantee of suitability for the location where it is being sold. That should be fairy obvious to anyone gardening longer than 6 moths!!
• They do not come highly recommended by CalPoly's Selectree or local extension services and master gardeners.

No one is saying they can't grow in SoCal.......they are just not the best choice for various reasons.

Why do you find it necessary to attempt to refute every point I made? It's very childish.

• Palo Alto is northern California and coastal. It is an entirely different climate and growing situation than southern California and inland SoCal at that (which is where any SoCal zone 9 is located).
• A single person reportedly growing them in a similar climate is hardly a blanket endorsement.
• Any plant that is not drought tolerant after establishment - not requiring weekly watering - is a poor choice for a drought stricken state under ongoing watering restrictions.
• Home Depot selling tropicals has nothing to do with the issue at hand.

They are an okay choice, not good and nowhere close to best. I'd encourage the OP to consider better suited alternatives

LOL!! Trying to change your tune after getting your hand slapped by Houzz?? Keep going....you're not there yet !!

And yes, you refuted two of my previous posts to this thread item by item.

btw, in another thread you indicated you live In New Jersey. So which is it, NJ or CA?? Or does your residency have multiple personalities like your multiple onscreen personas?

What a muppet!