98-112 Days to maturity. Plectranthus argentatus. Silver Shield Plectranthus Seeds. Non-GMO, Annual. Silver Shield Plectranthus is a popular and attractive herb. It is a versatile and easy-to-grow herb in the mint family that can add a unique flavor to your dishes. With the right care and attention, this plant can thrive in a variety of environments and provide you with an abundance of flavorful leaves to use in your cooking and blooms to beautify your space. 100 seed packet.