From my days as regional bird editor I can tell you folks in urban settings in south Jersey had a hard time attracting hummingbirds. Most reports were post-nesting reports like your's. Maybe you'll get lucky and one will stick into September, because it seems like you are make all the right moves.

I live on a loud urban street with mature trees. had sporadic single sightings from april 4th-early july while friends 20 miles out of town both west and south reported "dozens fighting over my feeders." last year I had southbound birds from july 24th-oct 9th. this year, daily sightings started july 10th. I do get juvenile birds, but I've never seen evidence of nest-building or mating here. I think there must be more days per year of seeing hummingbirds in the country than in a city.
your plantings do sound very nice. keep us posted.

I live on a fairly busy thoroughfare that also represents one of the borders between the city and the neighboring suburbs and often used by ambulances, etc., because it is wide and straight. However my little one found my garden oasis up here on my 18th floor balcony last August while on her way back down south, where she nectared on a reblooming "Red Prince" weigela and a blooming goldflame honeysuckle that I have here.

She ultimately returned here on June 5 this year and was greeted with a brand new feeder and quite a smorasbord of flowering plants! She had been coming about every 20 - 40 minutes like a clock, all day, every day since then, until the past week or so where her appearances have been a bit more sporadic. I'm thinking she might be raising young somewhere, although I have seen the yellow jackets out bothering her when she does come.

Last year she left sometime mid-August so I'm hoping she'll at least stick around until then before heading back.

Jenny lives in a high rise in Philadelphia and gets them all the time. I know when my daughter was at Fordham in the Bronx she called me up to go to the New York Botanical gardens native garden and there were dozens of hummingbirds well into September Also I remember seeing on the New York birding list some winter hummingbirds in a park down by (is it the battery?) lower New York and just this past January there were hummingbirds at the Smithsonian frequenting a salvia in gallery there in center of DC My daughter saw it. Sarah