Some things to consider:

1. Heat trapping (lava rocks gets hotter than bark mulch or other
organic) -- might make roots too hot
2. No soil amending abilities

As for #2, we have been using shredded mulch on our beds, and now have
really nice black soil there. It has improved over the native clay
wonderfully over about 5 years. When you go with rocks, this composting
process doesn't happen.

On the plus side, I do think the rocks look nice, and you don't have to put
on new mulch every year, as we do. But, we opted to apply the shredded
mulch yearly for the benefits to the soil.

Hope this helps!

-- pelirojaroja
-----------------------------------------------
"There is a garden in every childhood,
an enchanted place where colors are brighter,
the air softer, and the morning more fragrant
than ever again."

-- Elizabeth Lawrence
"Naomi Glass" wrote in message
...
We are considering a load of red lava rock as a mulch for
existing front lawn plantings and as a fill for areas to be targeted
for planting in stage 2 of our GET-RID-OF-THE-DISFUNCTIONAL-LAWN
campaign. Any pros and cons would be appreciated.

Naomi Glass
Kirkland, WA, where it's pretty dry out there...