The site is located in Redding (Northern California), Sunset Garden zone 9 and is on a school playground with dense red clay soils. The school was newly built (construction over the last 3 years) and as anticipated, some of the native blue oak that we worked hard to keep did not make it due to soil disturbances and excess water retention.

This particular replacement tree is located approx. 20 feet from the side of the building (located on the north to northeast side of 2 story building), and is located on the playground. The planting location is ringed by a 13 foot diameter concrete curb, with a circular 1 foot wide by 2 foot deep gravel trench just inside the curb under 1 foot of soil (connected to an underground drain system). Outside of the concrete curb, the ground is planted with turf watered by the KISSS underground drip system. The planting location also has the ability to have an independently valved water source to help establish a tree if necessary.

Because of the nearness of the building, I am trying to find a fast to moderate-growing deciduous tree with a relatively open canopy with a mature spread around 15 to 20 feet (or that can be pruned to maintain that spread). We hope the new drain system will keep the tree from becoming waterlogged, but need to find a tree that can tolerate wet to dry clay conditions.

We also need a tree that gets some height on it for shade and aesthetic purposes.

We'd thought of the more columnar acer rubra cultivars (Armstrong, Karpic), although they have a pretty dense canopy, or a more vigorous Japanese maple. We've had one recommendation for the zelcova serrata, "Green Vase," but don't know whether it will be possible to prune it to keep such a narrow spread at maturity, and the ones we have seen have a pretty dense canopy. We've also had one recommendation for a cornus nuttallii hybrid, "Starlight" or a cornus florida , "Cherokee Sunset".

Any thoughts about the recommendations we've had or advice of other trees to consider would be appreciated! Thank you!

I'd reconsider the columnar maples or perhaps a sweetbay magnolia, Magnolia virginiana. And although ornamental pears have a terrible rep throughout most of the country, I'd look into Pyrus fauriei 'Westwood' (Korean Sun). A non-invasive (at least along west coast) smaller tree that should fit into your limited space and like all pears, with a high tolerance for less than ideal drainage.

On other properties in our area, we've had some success with dogwoods in locations that don't drain well. But unfortunately, we don't know what species they are, and so are willing to consider them - but any advice is helpful!

Magnolias in our soils put up surface roots that would be a problem in the playground - we had considered the magnolia virginiana, but thought the roots would be a problem.

I'll look into the Pyrus fauriei "Westwood." I am not familiar with it. Thank you for the advice!