We use rock mulches quite often here in Southern Nevada. There are some plants that prefer rock mulches ... other do not .. those that can deal with reflected heat and prefer a mineral soil type do better with rock mulches ... keep in mind you could use rock to cover most of the yard and create islands of organic mulched beds for your plantings .. in other words getting the best of both worlds.

Maintenance wise rock mulches can collect a lot of debris .. keeping the rocks clean can be quite a chore. Weeding a rock area is also not a very fun activity and if you can't keep the rocks dry ( as we can easily in the desert ) then expect weeds. By the way I never have seen weed blocking fabrics that work so plan on pulling and / or spraying weeds. Save your money don't buy the fabric instead get more flowers.

Cost is another consideration .. in our area we have lots of stone making rock mulch somewhat economical. About $35 - $45 a cubic yard for the better stone in the 3/4 inch size. That covers about 150 square feet 2 inches deep. Could add up for a big yard !!

Most rock should last a long time where as organic mulches break down.

Good Day ...

And to continue Nevada's thought, don't even think about putting plastic under the rocks. It smothers the soil, killing the soil microorganisms, prevents water infiltration...and air. Eventually it tears, becoming unsightly and allowing weeds to pop up.

I have no problem with you using gravel as firebreaks.....such as long the property line and definately near the house. In fact in high fire danger areas keeping a 30 foot fireproof barrier around your house is critical. BTW, isn't an irrigated lawn acceptable near a structure as long as it remains green and irrigated?

How people here in the southwest deal with all the gravel and debris is to blow it out with high velocity blowers that also destroy hearing for users and people nearby...to say nothing of lauching debris and rocks into windows. The lawn mower sound has been replaced by blowers...grrrr.

As for weeds in rock, well, there's herbicides. I hate 'em but I use them in my limited rock areas.

Hi Mohave Kid & Crumpet, and thank you both.

That is all new wisdom for me. I observed some local rockscapes and started suspecting herbicides on the clean ones. We do get only very limited rain here (semi-arid; desert) and I plant for low-watering, so the rock areas might be alright on my property. Thanks for all this info.