Rudbeckia or coneflower is one of the easiest and most versatile of all annuals. There are intermediate varieties in many shades, and some have an unusual and striking green center or "cone" like the Pow Wow and Autumn Sun varieties. Rudbeckias need full sun to succeed and soil must be well-drained but have rotted compost or manure worked in before planting out. For container growing use multi-purpose compost with slow-release fertilizer mixed in. They are half-hardy (frost hardy) to 5 degrees Fahrenheit. Sow in February and March, transplant in March, grow in April, harden off/plant in May, flowers June - October.