This is a tree that is native to the Sydney, Australia area. It was brought to the Azores, where its only competition is the eucalyptus. They tried it in Hawaii and it was so successful that it is banned for its invasive nature. All warm areas, so yes, it was probably killed by frost. If you had the seeds, they are very easy to start - I regularly weed the babies. But it is in bloom now, and the air is filled with its scent.

Not so much frost as freezing and snow and lower than usual temperatures, possibly. They are just a teeny bit tender - planting recommendation for these is in Spring, in the shelter of a wall or fence, preferably south facing, with some protection in the winter - though none of that has been necessary for some years - up till this one!

I have been pleasantly surprised that my plant has survived our winter cold and freezing temps in North Northumberland....

Thanks Wylieintheazores and Bamboo. Can't say my pittosporum is invasive but it certainly has had a lot low temperatures and is only protected by some laurel. If I cut it down will it shoot again ?

Don't cut it now, whatever you do - if you're not convinced its dead by mid April, cut it then. You don't want to force new growth while its still cold.

I was concerned for my new one planted in the autumn - so I fleeced it. It has come through fine. If you get another one, try that on frosty nights.