Popcorn cassia (Senna didymobotrya) earns its name in a couple ways. One very obvious one is its flowers – spikes sometimes reaching up a foot in height, covered in round, bright yellow flowers that look an awful lot like their namesake. The other is its scent – when they’re rubbed, the leaves are said by some gardeners to give off a scent just like that of freshly buttered popcorn. Still other gardeners are less charitable, likening the smell more to wet dog. Smell disputes aside, growing popcorn cassia plants is easy and very rewarding.