Yes whole cumin is different to ground - smells nicer imo. Good basic spice that goes with everything (nearly). The whole seeds are usually dry roasted in a dry pan until they change smell to delicious. The change is unmistakable. Sumac is available at most colesworths, and sometimes at Aldi, and is probably included in most middle eastern spice blends. Rosemary is fine on potatoes too - I like a bit on roasted potatoes, not so much on mash - but its natural partner is pumpkin.