The Bremerton acacia shows signs of having frozen to the ground in the past and is of interest precisely because it is just about the only persisting one of much size known in the area. It is exceptional, like the azara in the UW Friendship Grove and the 50' eucryphia near Brian's place in Bremerton. Many others will have been planted elsewhere and frozen out in time. The late J. Witt of the Washington Park Arboretum once told me that there used to be a 50' eucryphia in a garden next door in the Broadmoor Golf and Country Club (most likely planted in the D. Graham garden) but it died in the awful 1955 freeze. An obvious difference between the two sites would be that the Broadmoor location is some miles from salt water, whereas the Bremerton site is quite close. If you are close to the beach the salt water keeps your minimum temperatures higher enough than even areas father inland but close by to make a difference in what you can overwinter. A cottage on Vashon just behind the Seattle/Bainbridge ferry dock has had a tall conspicuous abutilon for years. Even though this is a north exposure, apparently the salt water is keeping it from freezing out. I think I noticed it was still there during a recent visit even after this last winter, although the proof will of course be if it is seen blooming and full again this summer. One of the better embothriums I've seen was growing right behind the beach along a quite inlet west of Tacoma. It was the first bit of plant life behind the cobbles and sand, and was leaning towards the water as though responding to its proximity.

Zone 9 where? Really, the Sunset zone would provide a much clearer picture of your conditions. I live in Zone 9/Sunset 23. Clay soil can be a problem with Arbutus Marina. The lack of drainage makes them even more susceptible to Phytophthora. Even with good drainage, Phytophthora can be a heart breaker with these lovely plants. I have lost three growing in huge pots; one tree, in the ground (sandy soil), remains healthy (knock on wood). Arctostaphylos prefers sandy/rocky soils. Emerald Carpet also prefers acid soils. I haven't tried Emerald Carpet, but in my area (south Orange County CA), A. edmundsii ('Little Sur') and A. uva-ursi 'Point Reyes' are thriving in very bright shade/protected sun. The former beside a shed, and the 'Point Reyes' under Iceberg rose bushes. Not sure they would be thriving in full sun here. These are being irrigated with drip. Howards have not been easy in our garden. We have lost three out of four of the 1 gal. plants tried. But our watering system is drip, and these guys are known to hate drip. How are you planning to irrigate?

Speaking of climate - as in Sunset - Zone 21 I see the 2012 version of the Western Garden Book (Time Home Entertainment, New York) says the best flowering from Bauhinia comes from those located out of wind and on soils that are "semi-fertile". So if your planting site is out in the open and you are fertilizing your roses frequently or otherwise trying to give them a fertile soil (full exposure to sun and rich soil being two things typically provided for hybrid roses by enthusiasts) these factors may have some effect on how your new tree behaves.

Final tip about these...why let this thread stop at 35 or wherever we are now haha! Ericaceous plants are not hungry hungry hippos. Although they may tolerate and even appear to grow faster with regular feeding, my personal belief is it can be skirting disaster. Not going to go find an article connecting over-fertilization to root rot but I bet I could find >> 1. This genus, especially, really wants 'benign neglect'. Sure it would be different if you were growing, say, blueberries on sandy soil. In fact I just fertilized one of my blueberries that seemed to be lagging with a bit of ammonium sulfate, we will see if it perks up this year. Anecdotes and opinions are what they are but, the 2nd set of pics at the NCSU link above are of a hybrid strawberry tree in London. They are a feature of gardens there. In 2010 I saw a stunning one in Rye, a solid zone 9 town on the south coast of the UK, but later read at a gardening forum that it had died. I succinctly remember it had been underplanted with a lush assembly of shade perennials that SCREAMED 'we're being heavily fertilized'. The Cyclamen coum were already blooming and so big they looked like houseplants! So, house changes owners, new owner wants beautiful plants under their strawberry tree, fertilizes them and...bam...the water moulds loved the fertilizer, too! And took out the tree! So we can't be sure that's what happened, but something to be aware of. In almost 15 years I've fertilized mine no more than 2-3 times with scant amounts of Miracle Gro (no need for Miracid here, already incredibly acidic soil!) and it's done just fine. I've repeated it ad naseum, but the case of the Camellia 'Aida' in my garden and one very close by, grown by a PhD horticulturalist at Longwood...pretty conclusively proves to me the already known connection between too much nitrogen and a failure to harden for winter. First PV winter, mine had a tiny bit of scorching on the leaf edges, the one he was heavily fertilizing so he could size it up for breeding purposes died so dead it couldn't even come back from the roots! UPDATE: was reading an excellent page about the hybrid - I didn't know it seldom fruited but that makes sense. So it's a big trade off to lose the fruits I think! https://www.architecturalplants.com/product/arbutus-x-andrachnoides/