I'm starting a butterfly garden and am in way over my head! Can anyone help me? I live in zone 5 and the garden will be in a very sunny spot. I'm looking for low maintenance but colorful flowers.
Native plants are what you want. Natives are maintenance-free and work perfectly with the butterflies that are native to your location. There are all kinds of great native plants that will attract tons of butterflies, and while I don't know which plants are native to you, here are some that work best for me and should work great for you:
Butterflyweed is a member of the milkweed family. It's bright orange and attracts all sorts of butterflies. it's also the host plant for Monarchs. You can also plant Swamp Milkweed, which is taller and has bright pink flowers. Sometimes you'll find tons of caterpillars on milkweed.
Blue Giant Hyssop is one of the best pollinator magnets I have. It's generally short lived but super easy to grow and spreads by reseeding. Butterflies, hummingbirds, hummingbird moths, and even an endangered bumble bee has been seen on mine. As a bonus, goldfinches love the seeds in autumn.
Purple Coneflower is probably the number one plant you have to have in a butterfly garden to attract a wide variety of butterflies. They have a lot of hybrids/cultivars out there, but the true native specie works best.
Joe Pye Weed is most enjoyed by Monarchs, Swallowtails, and Red-spotted Purples.
Hoary Vervain is a short-lived but fast growing native, as well as a heavy self-seeder. I tend to see various Skipper butterflies on it more than anything else, but hummingbirds have been attracted to it here and there.
Rattlesnake Master tends to attract Spring Azures and Red Admirals in my garden.
It's not as widely known as it should be, but the number one nectar source for Monarch butterflies is Meadow Blazing Star (Liatris ligulistylis). Other plants don't attract nearly as many, including other Blazing Stars. For some reason, they really love this specific specie. If you have the time, look at some of the videos of this plant on youtube. You'll see what I mean.
Lastly, while it's not native, it's worth having if you have the room. Mexican Sunflower attracts tons of butterflies and hummingbirds, and can really help the monarchs and hummingbirds during autumn migration. It's an annual that grows really easy in dry sunny areas, but it gets big. Most seed packets say 4'-6' tall, but I've never had them that short. They always get 8' to 9' tall in my yard. I plant a row of them along my fence, and tie them up to the fence so the rain doesn't tip them over and rip them out of the ground.