Hello muddyshoes, sorry for the bringer of bad news, but all the penstemons in the gardens i tend have perished, have you tried cutting down a little to see if there are signs of healthy wood, most of the penstomens i have seen have completely gone brown and very brittle right to the ground inc the roots.

Wait - it may yet start showing new growth, so don't advise cutting back until/unless it does, and if you do want to cut it back anyway, where you live, don't do it before beginning of May.
PS - Julien, just seen your response (done at the same time) but this question is on Pittosporum, not penstemmon...

Appologies for the mix up, its been a long day, however the pittosporums i have seen have all been killed off too, all topgrowth, and main trunks completely dead.

My Pittosporum tenuifolium Irene Patterson has survived its 11th or 12th winter. Last summer I planted a Pittosporum eugenioides Variegatum and Pittosporum eugenioides Variegatum they look damaged but seem to have survived so I would wait and see as suggested MW.

I have 5 Pittosporums, all different and well established. Only one has survived last winter; the rest appear to have completely died, and I have now sadly made the decision to take them out. I live in Dorset, normally fairly mild, but I think the ultra low temperatures and snow were too much for them. In addition, it now seems I have lost two big, hardy Hebes; they seemed to have survived the winter, but over the last month have deteriorated and now seem dead. I am also alarmed to see that my 3 Viburnum Tinums have started looking a bit sick.

I'd be interested to know if anyone else in the south west has had a similar experience with well established shrubs.