Hardy winter plants

I work part of the week in a primary school and so far we have planted some heathers in the garden, and I would welcome advice on any other suitable plants for a garden area that is in places quite rocky. We are in a fairly rural part of Yorkshire and the field has little cover so I am expecting winter weather to be harsh. Other plants successfully growing, to indicate the type of land we have, include hollyhocks and sedum. I'm interested in either bulbs which will flower later (including spring flowering) and plants to be planted out now which will survive the winter. Thanks.

 

And for none-bulb stuff you can plant now that will be ok:

* Rosemary
* Thyme
* Lavender
* Sage (officinalis - ie the common vareity, tough as old boots, the cultivars that I know of will struggle in the situation you describe)

All that's assuming you're not right at the top of Yorkshire, at the top of the Dales where the snow gates close the roads for winter?