We don't have 30' spireas because they are not capable of living long enough and holding their stems up long enough to reach 30'. Long-lived shrubs like camellias do grow 30' tall, after enough time has elapsed. Redwoods over 300' tall still grow taller every year. The upper height limit determined by how far up they can "pump" water is not exceeded because when that happens the tops die back, to start over again. Uppermost annual tip growth may also be very slow on these towering, ancient trees. Which takes us back to what I said before, "halts completely yet remains vigorous and healthy". What shrubs have you seen that look great yet are not growing taller at all? Answer: none. Commercial sources don't want to scare people off. Give height estimations given a good dose of skepticism. And keep in mind these are usually for comparatively short periods of time, like 10 years. I've seen older specimens of plants repeatedly described as growing say, 6' tall that were multiple times that height.

I guess I haven't been keeping up with how many new Hibiscus there are. Yes, 'Midnight Marvel' and 'Summer Storm' and 'Brandy Punch' all look very good. I've been looking at my 'Kopper King' with a more critical eye this year because I've had it long enough for it to be settled in. I realize that there is the side of me that is just a plant collector and the side that loves a great landscape. I think in the case of KK, my plant collector side is pulled to this shrub. I really anticipate seeing those huge flowers open every year. They fascinate me for the short time the shrub is in bloom. But as a contribution to the landscape, I'm not loving it. In fairness I haven't attempted to shape it so, one more year before I decide whether to keep it or get something else. I'm glad there are other choices.

Hi, anyone know of a Canadian source for this Philadelphus cultivar, or (long shot) have a shrub from which I can get a cutting?

though it is a shrub.. which you could rejuvenate yearly ... and beat it back somewhat ... basically every year .. you could go in there.. and remove the tallest branches down near the ground ... so that they dont just keep growing up and up and up ... second link looks interesting.. from what it says: https://duckduckgo.com/?q=Philadelphus+rejuvenation+pruning&t=ffcm&ia=web doing the cutting isnt that big a deal.. but dealing with the cut brush can be ... and what i could do 10 or 20 years ago.. im not really interested in doing now.. so... unfortunately ... i have too many very big shrubs.. that in my youth ... would have been maintained better ... in other words.. dont plant a lifetime job.. just in case you lose interest ... now.. how about you try propagating the one you have.. if you think its the bees knees??? btw .. the bees love this plant.. lol .. https://duckduckgo.com/?q=conifers+in+alkaline+soil&t=ffcm&ia=web and come to think about it.. maybe your seller already knows how to do it ... and might do it for you.. if she could get some extra pieces for herself for the next sale??? .. work smart.. not hard... lol .. ken ps: there are variegated version.. and due to the reduced chlorophyl... are a bit less aggressive ... so will stay smaller longer.. though i have no idea if they would work in FL ... Philadelphus coronaria 'Variegata' this one stays rather small in my MI ... and burns like a crisp in august ... not sure it would favor FL at all ... if i find a pic of my green and yellow one.. .i will post it later ...