Three of the easiest-to-grow flower bulbs are Dahlia, Lilly, and Allium. All of these make great cut flowers and, if grown in the right zones, multiply over time.
Dahlias are hardy to zone 8. They prefer full sun when grown in the north and shade if grown in the south. The bulbs should be planted about six inches deep. If deadheaded, they continue to bloom until the first frost.
Lilies come in many different varieties and colors. They prefer deep, loose soil and plenty of moisture. Lilies should be planted in the sun, but the roots should be kept cool with mulch.
Allium bulbs should be planted in the fall, three inches deep and six inches apart. They are hardy in zones 4 to 9.