Culture
Prefers medium to dry, well-draining soil in full sun. Tolerant of occasional drought and poor soil. Best growth and flowering in fertile soils. Reliably winter hardy in Zones 8-11. Cultivation of this plant is dependent on the hardiness zone it is grown in. In warmer climates (Zones 10-11, possibly 9) this plant can be grown as a small, multi-trunked tree or large shrub. Vigorous pruning can keep the size and shape of this plant in check, as well as increase the number of blooms. Aloysia virgata is very sensitive to temperature, and even a mild frost can cause complete defoliation. Otherwise it is evergreen. In cooler climates (Zones 8-9, possibly 7) after a full season of growth, this plant can be cut back in a similar manner to a herbaceous perennial. Deadheading throughout the growing season will ensure continuous blooming, and pinching can keep the shape in check. In colder climates (Zones 6 or 7 and below), this plant must be grown in a container and brought indoors for the winter. After the first frost, the leaves will drop and the plant can be kept dormant in the same container in a dark, cool (60 F) area. Water sparingly. This plant can also be kept active through the winter if placed in a warm, sunny location inside before the first frost. However, white flies and spider mites can be issues when kept indoors in leaf.
Noteworthy Characteristics
Aloysia virgata, commonly known as sweet almond bush is fast growing, woody shrub or small tree native to northern Argentina. In climates where it does not die back in the winter, it can grow up to 15' tall. Its habit is upright to slightly arching, with long, thin branches. Slightly glossy, dark green leaves, ovate to lanceolate in shape, are oppositely arranged along the branches. Grown for its extremely fragrant white blooms, which emerge from the ends of new growth on clusters of flowering spikes. On hot, summer evenings, the fragrance can permeate the whole garden.
Genus name honors Maria Louisa (d. 1819), princess of Parma and wife of King Carlos IV of Spain.
The specific epithet virgata refers to the long, thin branches of this plant.
The common name refers to the fragrance of the blooms, which has a sweet odor reminiscent of almonds.
Problems
No serious insects or disease problems when planted outdoors. Specimens kept indoors are highly susceptible to white fly, spider mite, and aphid infestations. Over watering or poorly draining soil can cause root rot.
Uses
Where hardy, use as a summer blooming small tree, large shrub, or large perennial. Hard pruning and deadheading is encouraged to control its shape, as the fragrant blooms only form on new growth. Use in containers, rock gardens, or sunny borders.