Feverfew is a bush-like perennial of the chrysanthemum family that averages 18 -24" tall and can be 2-f3 t wide it will do better in the ground. Take care it can induce headaches and a very nasty rash and does not smell good that's why I stopped growing it

In a pot where its watered regularly and in good compost, it'll get 2 feet wide and tall easily, probably more - in the ground in poor soil where its drier, less.