Euphorbia polychroma
Pyrus calleryana ‘Aristocrat’ – Other than their unpleasant fragrance these trees are great.
Petunia ‘Potunia Cappuccino’ – Playing off the pink and yellow seems to be the best way to bring out the best in this new Petunia.
Centaurea montana ‘Gold Bullion’ – Not that attractive a plant when in flower or not, but the buds are amazing yellow with black details. Doesn’t make up for its problems in all other areas.
All Andrew's Plants 
I remember being really impressed with Euphorbia polychroma at the ex-job. Maybe I should get some?And the Centaurea montana sure looks like a nice plant. What are these "other problems" of which you speak?
Euphorbia polychroma is a wonderful plant with absolutely no drawbacks, well, other than the fact that it doesn't get too big, It's such a beauty that I wish it would spread a little!
Mostly just I suppose that I'm not a fan of the flowers (something about the red and blue, combined over the gold leaves of 'Gold Bullion' and it just doesn't do it for me), and it only flowers for a short time, and after it finishes there's nothing particularly special about the leaves.If I had to have one it would definitely be Centaurea montana ‘Amethyst in Snow.’ The colours just work better together on that variety.I've been thinking about getting a Euphorbia polychroma 'Bonfire' but there's something about the straight species that just seems so right. In my case the small size is just another point in its favour!
I love euphorbia polychroma – I think its the best euphorbia on the market. As for Gold Bullion its nice but if its like its cousin where it develops mildew after flowering and spreading its roots like a weed and popping over the place from the slightest bit of root – then I'll just pass it by.