Oxalis Triangularis bulbs - Purple Shamrocks for Indoors or Out! Oxalis Triangularis bulbs - Purple Shamrocks for Indoors or Out! Most gardeners choose plants based on their flowers, but leaves are a big part of what we see year round. Triangularis leaves are a stellar purple, with deep rose patterning and a zippy geometric shape. For small plants with huge impact, mix triangular with silver leafed partners like Japanese ferns or artemesia or chartreuse mates as our photo shows. Exceptionally handsome in light colored ceramic pots. Also excellent as houseplants on a sunny windowsill for rich color all winter. Common Name: Oxalis Triangularis, purple shamrock, lucky shamrock Botanical Name: Oxalis Triangularis Exposure: Full sun to light shade