My experience with Hymenosporum flavum is from a California perspective, and they grow well here, but do seem to prefer sandy loam soils over heavy clay soils for best year round appearance. Did the leaf drop start to occur after either a prolonged dry period or a cold snap? These two things can cause them to drop foliage here, as well as the roots staying too wet. In fact, this tree can often struggle when planted in pure clay, although as they get larger they seem more tolerant. They also tend to drop leaves with the onset of colder weather, and push rapid new growth when it warms up again. If you know you don't have a drainage problem, I'd suggest you wait to see if it pushes new growth once the height of winter is past, although if you are located in Sydney right on the water, your winter couldn't be all that cold to cause leaf drop. Maybe try an organic or slow release fertilizer to see if that helps...

There is also a noticeable difference in vigor of plants within a block of seed grown trees at nurseries here, and I always look for the healthiest specimens over the larger ones when selecting this tree for gardens. It often seems that straggly plants never amount to much here, even after they have settled in. I love using this tree, as it can bloom multiple times from spring into fall, never gets too densely shading, fills the bill when something tall and narrow and evergreen is wanted, and the fragrance is heavenly. Surprising to find that a subtropical rainforest species from Queensland does so well in a summer dry Mediterranean climate, and is even quite frost hardy, easily tolerating down to 22F freezes here, with no permanent damage except complete defoliation.

Thanks bahia

we have had both a prolonged hot summer and then a relatively cold and wet onset of winter (coastal temps down to around 7c of an evening 9c to 15c of a day and rain consistently for about 6 weeks)limited clay - sets in at around 1.5 metres (we know this because we excavated for a pool prior to planting) top soil is relatively sandy, well drained - we did add some lime as a result of our initial research, just to raise the ph.

sounds like a wait and see job....... Just hate seeing the leaves drop when I know they are not suppose to.

Any feedback from those in Sydney - particularly the coast - I don't see many of them around here so hard to now what other native frangipanis are doing at present.

Cheers, L

I realise this is a very old thread however for what its worth there’s 6 of them here at a Unit block in Kilmore central Victoria and while decent temperatures during the day, it does get cold overnight and in Winter. Most of them grow profusely in Spring Summer (when its not too hot) and drop their leaves in Autumn Winter. All 6 trees have grown high but are quite weedy so I guess they are sensitive to conditions. Clearly the wrong climate down here - im surprised they keep growing at all, but they do.