I don't know but it looks identical to some of my leaves. As you said, the tree is growing well but several leaves look just like that. Maybe glomerella leaf blotch? I've tried to attach a link, hope it works. Here is a link that might be useful: glomerella leaf blotch

Lellie, lovely photos but probably best posted over on the gallery.

When I started using Houzz I was amazed at how accurate the results of my searches were (in addition to the size of the photos database). It was a great resource. More recently when I've prepared to undertake projects, I've noticed that I just don't get the same, accurate results. My searches are riddled with results that just aren't pertinent. I think this is due to the incorporation of advertisers from my city and surrounding areas (contractors, builders, and others). There are enough ads (or results that are somehow influenced by someone who has something to sell) now to really hinder the flow of design ideas. I guess many internet sites end up using advertisers but it morphs the user experience. It's really made using Houzz less fruitful.

I have pointed out several glitches to them. In addition to the whole annoying sideways photo thing, I've found that links I post move or disappear completely after I hit submit. Then I need to go back in and do it again. If you highlight and try to delete it wants to leave the page. It's an adaptation, not the original forum set up that was popular before. The one piece of information I was given after several complaints is that Houzz is optimized for the Google Chrome browser. If you use Chrome here photos post properly and the links don't disappear. I use Chrome for 1 or two things because it is rapacious about tracking every single thing someone does. Then Google collects and profits from the information and your privacy is invaded more than it usually is by Firefox or even IE. Ipads use Safari. You'd think a design site would be optimized for that and mobile but on mobile the site isn't scalable. Houzz should address this. They've been told. They don't seem to care.