10 Bulbs Oxalis Iron Cross Good Luck Plant Green Shamrock Four Leaf Lucky Clover Oxalis Iron Cross Robust Bulbs, Lucky Clover, Good Luck Plant, Green Shamrock Plant, Four Leaf Clover, Heart Shaped Leaves, Oxalis tetraphylla 'Iron Cross'. If planted in early spring it will grow and flower throughout spring and summer. Zones 8–9. Some bulbs can survive a cold winter but in areas with frost they should be kept in a cool dry place over winter and replanted in the spring. The bulbs will multiply by autumn.