What are annual flower varieties that attract butterflies?

[Stefanie Stamp]

I want to plant some colorful flowers in my garden to attract butterflies. What flowers are good ones?

[Anaya Sherman]

Adult butterflies are attracted to red, yellow, orange, pink, and purple blossoms that are
flat-topped or clustered and have short flower tubes. Plant good nectar sources in the sun – Your key butterfly nectar source plants should receive full sun from mid-morning to mid-afternoon.