I suggest you check out the website of The Cultural Landscapes Foundation at tclf.org. Many American landscape historians are plugged into this group, headed by Charles Birnbaum, FASLA, who has long been one of the leading figures in American landscape history and preservation. There's a place on this website for posting research inquiries and you might have some luck there.

You may have better luck in searching landscape history archives in the US, particularly those relating to his projects that you mention. He doesn't seem to be known here.

Good to hear from you. Yes it is the hardest for my dear sweet Dad. He has not been feeling well...the heat and his blood pressure has been low...it is usually high...taking him for doctors visit and try to get him doing better. He is staying in out of this heat. Glad to hear your violets are doing well. I would love to come out for a visit....wouldn't it be nice if we could spend sometime on the beach....something to think about and maybe plan for next summer!!! Again good to hear from you. Nora

They seem to be growing back, yes. In the process of cutting them back, I believe I also eliminated those nasty caterpillars that get on them every year -- I still don't know how to treat that problem, either. I've tried Bayer pesticide and even pouring some cold brew coffee (lots of caffeine). Conversely, I had a pot outside that had petunias that would start growing back after winter. I thought that was rather interesting, especially for zone 5 here in New England. Most of the do not :) I have read that you need to keep pruning petunias throughout the year. But if I can just figure out how to keep these pests off my plants, I think they will fare better. This year, I think some kind of fungus or microbe attacked them in addition to caterpillars.