Key Points It's important to divide hostas so they stay healthy and don't overcrowd other plants. Divide hostas in the spring or early autumn. And while they're very low-maintenance, like anything in the garden, hostas do require care and attention in order to thrive. "Hosta plants that aren't divided keep growing, which means they can invade the space of nearby perennials," adds Jabbour. "In spring, continue to water several times a week, depending on the weather," adds Jabbour.