All across the United States, Monarch butterflies are making their massive migration southward. Some of these insects will travel 2,500 miles to avoid the harsher winter temperatures experienced in their spring and summer homes.

Monarchs are thought to be the only insect that travels such a distance every year during their migration, but the really impressive thing is that they are not the same butterflies who made the trip north last year. This year’s monarchs are up to four generations removed from those that came north to their breeding grounds last spring.

Colonies have even been tracked returning to the same trees year after year, and the how is a still a mystery. New genetic studies have shown that they can cover large distances because of one specific gene which allows them to fly very efficiently, but so far no conclusive data has been compiled on how they know where to go.

Unfortunately, population numbers have been on the decline for this remarkable species in recent years. Habitat loss, unfavorable weather, and pesticides have all been cited as potential reasons for this decline, and news coverage has many gardeners on the migration path wondering what they could do to help.

The migration area is extremely wide, encompassing just about all of the southern and western United States, and for green-thumbs the answer is one word: milkweed.

Milkweed plants are the food eaten by monarch larvae, and mother monarchs will land there to create their “nurseries”.

Milkweed comes in many different varieties, and most of them are tough, drought resistant plants that will sprout again next year, even if defoliated by baby monarchs. These plants may also attract other types of insects, so gardeners must take that into account when deciding to help the butterflies. If you do decide to plant milkweed, chemical pest deterrents should be avoided as they will discourage monarchs as well.