Seeds are easy to start, but because plants do not flower well until the second year, you may want to save time by buying container-grown plants. To start seeds, barely press them into moist seed starting mix, enclose the containers loosely in a plastic bag, and keep them at 60 o F and in moderate light. Seedlings should appear in about two weeks and can be shifted to larger containers a few weeks later. In my zone 7 garden, I keep seedlings outdoors in pots through their first winter, then set them out in the garden when they are a year old. Plants need at least 6 weeks at or below 40 o F to flower, but flower best with at least 12 weeks at these temperatures.
Balloon flowers develop heavy gnarled storage roots, so it's easy to move plants if needed.
And, should you want to propagate them, simply take a heel cutting in late spring, when the new stems are about 2 to 4 inches long. Pot the cutting, keep it constantly moist, and it should quickly take off. I get close to 100 percent success with this method, compared to only about 50 percent survival of tip cuttings dipped in rooting hormone and set to root in a sandy potting medium. To get the most prolific bloom, situate plants in a well-drained site and fertilize them to support strong growth. In fall after trimming off the dead stems, I add a little more mulch and then put the wire support ring back in place.