Catnip is a common herb that thrives in much of North America and is very easy to grow. While you’ve probably heard that catnip makes cats something like tipsy, you might not know that this effect is an inherited trait and does not affect all cats. And if you’re planning to plant catnip—for your cat or yourself—you should realize that there are different types of catnip and that all common types are invasive. This means they can take over your garden even if they don’t take over your cat’s mind.Catnip plants can grow up to 3 feet tall and wide. Their small white or lilac-colored flowers grow in clusters. The stems of these fragrant plants have the squarish shape typical of the mint family to which they belong. Catnip plants enjoy sun and are drought-tolerant ground covers, making them a good choice for sunny, dry areas where many other plants would struggle. But they offer little ornamental value. Nepeta cataria is the preferred herb to grow for cat-lovers; fewer cats are attracted to the ornamental types, such as Nepeta mussinii.They do best in full sun to partial shade. Like so many herbs, this perennial thrives in poor soil that is well-drained. Catnip plants prefer a slightly alkaline soil but are not very fussy about the ground in which they grow, as long as their roots are not constantly sitting in water.