hvander, we grew this annual Snow-on-the-Mountain one year. It likes to grow straight up and is fairly tall. You may benefit from pinching it. We just planted real close (about 8-10" centers) and grew through a horizontal trellis.

They turned out fine and were useful and long-lasting in bouquets. The reason we didn't grow them again was because of this: "Handling plant may cause skin irritation or allergic reaction." I didn't have a problem but my wife got rashes on her hands. If you wear gloves, you should be okay.

Steve