Yellow Walking Iris or Neomarica longifolia. This upright evergreen perennials with yellow-green foliage growing to 2 feet tall is a member of the iris family with lancelike leaves that arise from rhizomes growing just below the soil surface. Plant in filtered sun and apply general garden fertilizer once each month in March, June and September. Prefers a moist soil; water at least once a week during hot, dry weather. It is easy to start new plants by dividing older clusters. Also remove new plants from the ends of flowering stems that bend down to the ground to grow roots and shoots thus the name walking iris. Plants are severely damaged by freezing weather but usually grow back from rhizomes near the ground. Remove arching flowering stems before they root in the soil to keep plantings in bounds. Walking irises are ideal plants for shady garden sites. The plants grow well in the damp sites and bog gardens.