Angelonia, commonly known as Summer Snapdragon, is a favorite bedding plant prized for its colorful flower spikes and exceptional tolerance for high temperatures. Whether this plant returns every year depends entirely on your local climate. Angelonia is a perennial only in specific, frost-free regions. For the vast majority of gardeners, it must be treated as a heat-loving annual that completes its life cycle in a single season due to its inability to withstand cold weather.
The Geography of Survival
Angelonia (Angelonia angustifolia) originates from the warm, tropical climates of Central and South America. Classified as a tender perennial, its root system is not adapted to survive frozen ground. Angelonia can reliably survive the winter outdoors only in USDA Hardiness Zones 9, 10, and 11, where temperatures seldom drop below freezing and the ground does not freeze solid.
In these warm zones, such as coastal Florida or Southern California, the plant continues to grow year after year, sometimes increasing in size. However, in Zones 8 and colder, the onset of winter weather seals the plant’s fate. Temperatures below 50°F slow growth significantly, and sustained exposure below 40°F causes direct damage. Frost leads to rapid cellular death, killing the entire root structure and necessitating yearly replanting.
Optimizing Summer Growth
For the months the Angelonia is actively growing, providing the right conditions ensures a continuous display of color. This plant demands full sun exposure, requiring a minimum of six hours of direct sunlight daily to maximize bloom production. Angelonia thrives in the heat and humidity of summer, conditions that cause many other flowering plants to wilt or stop blooming.
The plant performs best in well-draining soil rich in organic matter, ideally with a slightly acidic pH between 5.5 and 6.2. While established plants possess good drought tolerance, regular watering is recommended to keep the soil consistently moist without becoming waterlogged. To support its continuous flowering habit, a monthly application of a balanced liquid fertilizer is beneficial.
Strategies for Overwintering
Gardeners in colder climates who wish to save a specific variety of Angelonia have two primary options for winter survival. The first is to bring the entire parent plant indoors before the first expected frost. Before moving it, prune the plant back severely by cutting the stems down by about two-thirds to reduce its size and help it adapt to lower light levels.
Once inside, treat the Angelonia as a houseplant, placing it in a bright location such as a south-facing window. A cool room temperature around 65°F is often preferred. During the winter, significantly reduce watering, allowing the top layer of soil to dry out slightly between waterings, and stop all fertilization as the plant enters semi-dormancy. The second, often more reliable strategy is to take stem cuttings late in the season.
To propagate new plants, select three to six-inch cuttings from the non-flowering tips of the stems. Remove the lower leaves and insert the cut end into a container filled with a well-draining, soilless potting mix. Applying a rooting hormone can help speed up root development. These small cuttings require bright, indirect light and consistent moisture until a healthy root system develops, providing vigorous young plants ready for spring.