Milkweed is the liver of the garden world. You know it's good — good for pollinators in general, and monarchs in particular. In fact, milkweed is the only plant on which monarchs lay their eggs and that provides food for monarch caterpillars. It also is a major source of necessary nectar for adult monarchs. But it can be hard to like.

Common milkweed (Asclepias syriaca), which can grow to be 5 feet tall, is a bit gangly. And with its clusters of tiny, inconspicuous flowers, it's not much of a looker. Besides, it's unruly. In fall, its seed pods split to let loose a passel of seeds, and it spreads by runner, making it a less-than-welcome native in many a well-planned garden.

Thank genus there are more than 100 species of milkweed, many of which "are appropriate for you backyard garden — and even for formal gardens — because they behave well," says Adam Baker, a pollinator ecologist and a technical adviser for Davey Tree.

Take orange butterfly weed (Asclepias tuberosa). This garden-sized beauty tops out at 2 feet and boasts showy heads of bright orange flowers. Then there's swamp milkweed (Asclepias incarnata), a fairly compact plant (2 to 4 feet) with clusters of tiny mauve flowers. Or whorled milkweed (Asclepias verticillata), with its slender leaves and flat-topped white flowers.

But one colorful milkweed, tropical milkweed (Asclepias curassavica), is a no-grow for any monarch lover. In warmer climates, this nonnative promotes a parasite that can harm monarchs. So pollinator proponents ask that you avoid it entirely.

While milkweeds are essential for caterpillar monarchs, adults also need nectar from plants that bloom when milkweeds typically do not. By putting in complementary plants like coreopsis, aster and goldenrod, you can help feed monarchs through the growing season.

Baker recommends buying milkweed plants rather than starting from seed. The plants are tough and can grow in poor soil, but the seeds are slow to germinate. "There's a reason why milkweeds produce a million seeds," he says.

This spring, shop your local garden centers for the well-behaved milkweed species. Some shops and plant catalogs also offer butterfly and pollinator plant collections. Garden for Wildlife, part of the nonprofit National Wildlife Federation, offers collections and plant sets. (To order a collection, which is selected by eco-region, go to gardenforwildlife.com.)

"Planting even a few milkweeds in your yard does make a difference," says Baker. Every patch of those hardy perennials helps build a network of monarch "way stations" that aid the much-loved butterflies in their awe-inspiring migration. 