Hallo Panderson - Welcome to GoY.

Answer 1. Yes, Oleander should be quite widely available. I'd ask at a reputable Nursery, or google for your nearest stockists.

Answer 2. They don't like clay soil - you'd have to improve it with lots of organic material, well-rotted manure and horticultural grit.

You could grow a compact version in a large pot, though!

Hi Spritz - many thanks - do I mix the grit in with the soil improver or surround at the top?

Dig it all in! If you can leave the clay soil rough over winter, then the frost would help to break it down... once you start planting, always dig a bigger hole and back-fill with compost & grit - your plants will thank you for it, and the soil will gradually improve. Also - if you mulch regularly, the worms will help to take the orgnic stuff down.

Thanks Spritz much appreciated

:-)