Clau soil particles are a mineral and do not "break down", it is the organic matter thaat gets mixed into the clay that gets digested by the soil bacteria. Some types of clay do not seem to allow organic matter to mix, there seems to be some kind of barrier at the soil/mulch interface that prevents mixing so those soils need to have some organic matter tilled into the soil first. Once that is done then mulches add to the OM in the soil with no problem. However, wood chips and shredded bark seem to be the most common types of mulch material that presents this problem. I would find some good compost and work that into that soil first and them apply the mulch.

Thanks for the suggestions! blakrab: Diciduous is ok. I'm surrounded by evergreens, so it's nice to have some diversity. not sure if we have any other open space to plant more though (property is overrun by coast live oak which sprout like weeds here. Every year I pull out about 20-30 saplings, and seems like I'm making no dent in the growth density here... every few years I have to have one cut down since they start crowding eachother too much). I'll take a close look at the Texas persimmon. Is that anything like the persimmons you find sold in stores? (orange fruit)? There are few of those in the area. if so, may be there'll be enough in the area without having to plant another in our lot... hoobv: it's a pretty densely vegetated hillside property, so fire is always a concern. But never really thought bout tree-fire exposure (we're usually more concerned with shrub/grass fire). I said 15ft, but just looked at the survey map, and it seems like it's actually more like 25 ft from the house. making a terrace is an interesting idea. the tree can be taller, as long as it's the type that is conducive to shaping/height reduction management. but taller tree usually means faster growth (may be) and hard to manage? and thank you for the tree selection guide. I'll ahve to take a look at that. An arborist who just came by recommended chinese pistachio. He said around here, it doesn't get much bigger than about 25ft or so, and has great fall foliage, drought tolerant.. doesnt require too much water in the summer so won't hurt the juniper either (I called it juniper, but arborist said cypress, so... hmm). The tree sounded good until I found out that it has a potential of growing to 60ft.. i'll have to do more research on that tree.

I went with 3 crepe myrtles from a local nursery. They fit the bill as far as lower branching (check), nice glossy foliage (check), good fall color and nice bark. They were also relatively inexpensive. The $64,000 question is will they bloom in this spot, with intermittent morning and afternoon sun. I think I'll be OK either way, although of course I'd prefer them to bloom. I looked hard to dwarf or Asian forms of Mountain Ash but couldn't find any (I went to 3 pretty big nurseries south of Seattle) that met the bill (I really wanted to stay under 2o feet of height and the most common European and American mountain ashes get larger than this). Ironically, it is evident that my crepe myrtles are somewhat water sensitive (I suspect they are potted in a potting mixture that is too dry). In the mid-Atlantic (where I used to live), they were legendary for their drought & heat tolerance. The ones I have, I suspect if they went 8 or 9 days without water, they'd be dead. They'll be planted soon. Goofy

why didnt brandon give his own link .. maybe in the other post?? .. see link below ... i would NOT go with compost .. after all... IT IS COMPOST... and that word means its NOT SOIL ... i would go to a soil depot and get a good top soil-sand mix ... something that when you take a handful ... and try to squeeze it like a snowball ... holds for a moment .. and then falls apart ... that meas its friable ... as compared to say.. your clay ... which mever falls apart ... so air cant get in.. and water out ... if you plan on planting many things ...or building beds.. have them deliver a truck load... and just store it for when you need it ... again... do not confuse soil ... with compost ... and do understand ... the tree will happy grow down into the clay ... the problem with the clay ... is the transplanting ... and water management.. until the tree can get its own roots down into it ... if your lawn is ferted ... or will be.. the tree will never need fert ... and frankly .. i would be of the opinion.. that the little berm you build.. will ever need it.. trees just dont need all that much from us ... the leaves are food making machines.. so if you grow the leaves... and the tree grows the roots.. you should be all set ... i would also suggest.. you go no bigger than a 4 footer ... cost is significantly less... and it will get established.. and probably outgrow the larger plant.. in 5 years ... i like to say.. there is no instant gratification in trees ... you cant buy time ... tree time ... ken https://sites.google.com/site/tnarboretum/Home/planting-a-tree-or-shrub