Angelonia, also known as summer snapdragon or angel flower, produces numerous blossoms resembling snapdragons in shades of white, pink or purple, depending on the variety. The plant tolerates heat, humidity and drought, and grows as a perennial in USDA hardiness zones 9 through 11. Elsewhere, the plant grows as an annual that dies back when temperatures drop in the fall and winter. Gardeners in cooler climates often grow angelonia in containers for easy over-wintering indoors.
Site and Soil
Angelonia plant performs best when planted in late spring in an area that receives full sun and consists of fertile, moist soil rich in organic material. In hot, sandy areas, angelonia prefers partial afternoon shade to protect against scorching. In most areas of the United States, the angelonia plant performs as an annual, but plants grown in containers may be brought indoors through the winter. For container-grown plants, high-quality moist potting soil provides the best results.
Once established, the angelonia plant becomes very drought-tolerant and requires watering only about once per week, or whenever the soil has dried. Although the plant can survive with less moisture, blooming will suffer. In very hot temperatures, container-grown angelonia plants may need more frequent watering. A layer of mulch added to the soil surrounding the plants prevents soil-splash, which may cause damage to the foliage and flowers.
A light, monthly application of 10-5-10 NPK water-soluble fertilizer formulated for flowering plants provides the nutrients necessary for blooming. Mixing an extended release fertilizer into the back-fill while planting helps boost growth throughout the season. Avoid over-fertilizing, as this causes the excessive growth of foliage and less flowers, and do not feed during the winter months when plants grow less vigorously.
Container-grown angelonia plants are brought indoors when average nighttime temperatures drop below 60 degrees Fahrenheit. When placed in an area that receives bright, direct light and watered once per week, the plants will survive the winter. Place them back outdoors when temperatures rise above 60 degrees Fahrenheit in spring and resume regular care. If left outdoors when temperatures drop, angelonia plants die and do not return the following year. In zones 9 through 11, plants allowed to remain outdoors all year will behave as perennials, but should not be fertilized during the winter months.
Angelonia plant seeds are difficult to find and most gardeners prefer to propagate by taking cuttings. Rooted cuttings purchased from a local nursery perform best, although cuttings may be taken from mature plants if necessary. Applying a root hormone to tip cuttings helps expedite the rooting process. Place cuttings in a well-drained rooting medium and keep at a temperature of around 75 degrees Fahrenheit. Rooting will occur in about 10 days.