German violet, also widely known as Persian violet, is a flowering biennial that produces lavender-blue blooms with prominent yellow centers on top of bright glossy green foliage. It is commonly grown in borders, beds, containers and planted en masse as a ground cover. It is also sold as a seasonal indoor houseplant. German violet flowers in spring and summer and must be protected from winter cold to achieve its biennial life cycle.
Water your German violets well in the fall to help prepare the plant and surrounding soil for wintertime drought conditions. Hold off on fertilizing in the late summer and fall to prevent a surge of new growth that will be killed off by the cold.
Cut back your German violet in the fall after the first frost occurs, and the plant is wilting and dying back. Cut the violet stems down to the crown of the plant with secateurs to approximately an inch above the level of the soil.
Mulch over the crown of the plant with at least a 3-inch deep blanket of organic mulch to protect the plant roots from the cold. Use compost, well-aged manure or shredded bark for the best insulation. Organic mulch will help boost the nutrient value of the surrounding garden soil as it degrades over time.
Clear away the mulch blanket in the spring after the last frost has passed and ground temperatures have warmed. Gently brush away the mulch immediately covering the crown, but leave the mulch surrounding the roots to hold in moisture and protect the plant for any unexpected late frosts.