Lavatera is a genus of of flowering plant in the Mallow (Malvaceae) family. This large family includes annuals, perennials and biennials. The flowering shrubs grow up to 6 feet tall and 6 feet wide. The stems vary from woody to green and fleshy. Annual lavatera mallows reproduce from seed each year while perennial varieties, such as the tree mallow, last three to four years before dying back. Perennial lavatera mallow plants are hardy to USDA planting zone 8. Lavatera mallow plants are not frost hardy, but annual varieties will flourish during the warm summer months.
Turn over the soil in the planting area. Lavatera mallow plants grow well in loose, well-draining soil. If your soil is heavy and clay-like, add organic material to the soil until it is light and crumbly to the touch.
Plant lavatera mallows outside in the late spring after the last frost has passed. Select an area that gets full sun throughout the day. This fast-growing shrub cannot tolerate shaded conditions.
Water once a week during the spring and summer months. Lavatera mallows thrive in slightly dry soil. Over-watering will stimulate leaf and stem growth while diminishing the amount of flowers the plant produces. Discontinue watering in wet or rainy weather.
Avoid fertilizers and plant food products. Lavatera mallows are light feeders; soil that is high in nutrients will hinder flowering. Add two to three handfuls of compost around the base of the plant once or twice a month if the soil is nutritionally poor.
Cut the plant back to the ground when it turns brown in the fall to improve the aesthetics of your winter garden. Leave perennial lavatera mallows until they begin to fade in the third or fourth year before cutting them down to the ground.