Guess big government starts with the HOA.

Any of the larger ornamental grasses a possibility?

What else... My neighbor has a dwarf pear(?) tree on a terrace.

Maybe a Japanese maple or two. Really it looks like a neat place to get some dwarf conifers or Japanese maples right up at eye level. Even some flowering bulbs.

Would they accept trellis on/in front of the shed walls with climbers on them? Or espaliered fruit trees in front of the shed?

Thanks for the suggestions.

Some questions - Do you think Japanese maple roots (shallow, tight diameter?) would be ok for the retaining wall? I'll also look into the conifers. Are there some that will reach 12-15' and are also have a tight diameter in their roots?

I also have been thinking about installing a trellis. However, any "structural" addition requires a new HOA approval. (Backstory: the shed was approved by the HOA years ago and they "rescinded" that decision, requiring trees, etc the shield the shed.) The espaliered fruit trees idea looks awesome. I'll have to decide how much work I want to put in for upkeep!

Have you considered something along the lines of Metrosideros collina 'Springfire'?

The Metrosideros collins might look to be a bit big rooted for the retaining wall level.

Thoughts on lining the retaining wall level with a row of emerald green arborvitae, thuja occidentals 'smaragd'? I saw a bunch at Lowes and says the average size is 15'Hx4'W, spacing 4'.

and are also have a tight diameter in their roots?

==>>> i have no clue what you are meaning ...???

no tree has tight diameter roots ... either in width nor spread .. whichever you are meaning ...

in 30 odd years of reading catalogs.. and studying plant .... i never heard that term ... and if you are hearing that from some dude trying to sell you a plant .. then walk away from him.. because he is using large animal excrement on you ... if you get my drift ..

ken

For 12' you do not need a tree. The right size of shrub will be perfectly adequate, and a medium shrub will have a more restrained root system than a tree genetically determined to grow 25'+ tall. If your HOA has an "approved" list of shrubs look there first.

If you are coastal bay area, look at Azara microphylla and/or one of the Pittosporum tenuifolium selections that are narrow such as 'Tasman Ruffles'. Not good for inland heat eg Walnut Creek.

This post was edited by hoovb on Tue, Apr 29, 14 at 21:13

"Mature size" is the average size at 10 years. So if you divide the "mature" height and width by 10, that is how much it grows per year (on the average, probably, more or less, depending on conditions, etc.).

And when trees or shrubs reach their 10-year-old "mature" size, they continue growing at the same rate....

--->And when trees or shrubs reach their 10-year-old "mature" size, they continue growing at the same rate.... That isn't really how it calculates out. Some shrubs are at the end of their life span in 10 years, and some plants are still youngsters at 30+. They do not grow at the same rate throughout their lifetime. Some start out slow, then get established and grow at a quicker rate until mature. Then they may begin to increase in size at a slower rate. It is similar to saying our one year being equal to seven for a dog.That isn't how dogs grow and mature either.

If you're in a cool summer part of the Bay area, how 'bout a few Chusqueas?