sweet holly: http://animalcrossing.wikia.com/wiki/Bush
scroll to the bottom and there will be a picture of the different bushes, the very last (with the pink and red berries) are the sweet hollies
Both are shrubs, I believe. The guide shows the Sweet-Olive Start as a sapling, but not what it looks like once it's fully grown. It'd be great if you could get a screenie of it once it's all growed up!