Agapanthus spp. and hybrids: Agapanthus, African Lily, Lily of the Nile

This document is part of a series originally written by Edward F. Gilman.

Introduction

Agapanthus is a genus of plants that contains two evergreen species (A. praecox and A. africanus) and six herbaceous species. These species are from southern Africa and have been cultivated in the United States for over two hundred years. A. praecox and A. africanus have become extensively hybridized between themselves and with the deciduous species, producing the majority of Agapanthus commonly found in the horticultural trade today. Many of the plants which are readily available are hybrids of A. praecox, which have been selectively bred to produce a variety of flower colors and shapes, increased blooming period, and higher disease resistance. There are hundreds of cultivars available in the horticultural trade.

Agapanthus is an herbaceous perennial with an upright growth habit, and a height of 2 feet and spread of up to 3 feet (Figure 1). Dwarf selections are available with a smaller growth habit. This plant has fleshy evergreen strap-like leaves (excluding deciduous species) that can range from 8 to 24 inches in length (Figure 2). It produces clusters of large blue, lavender, purple, or white funnel-shaped flowers atop long stalks in summer (Figure 3). Seed pods appear after the flowers, and are showy brown capsules (Figure 4). There are many cultivars with variations in flower shapes and colors (Table 1). The umbels are very showy, containing between 20 and 100 flowers each, and make good cut flowers for arrangements. Agapanthus attracts pollinators and is well suited for a variety of landscape uses including making an impactful mass planting or groundcover, in containers or above-ground planters, as accents or edging, or is appropriate as a houseplant.

General Information

Scientific name: Agapanthus spp.

Pronunciation: ag-uh-PANTH-us species

Common name(s): Agapanthus, African lily, lily of the Nile

Family: Amaryllidaceae

Plant type: perennial; herbaceous

USDA hardiness zones: 9A through 11B (Figures 5 and 6)

Planting month for zone 9: year-round

Planting month for zones 10 and 11: year-round

Origin: not native to North America

Invasive potential: not known to be invasive

Uses: mass planting; container or above-ground planter; groundcover; accent; edging; border; attracts pollinators, butterflies, bees, hummingbirds; suitable for growing indoors; cut flowers

Availability: somewhat available; may have to go out of the region to find specific cultivars or selections

Description

Height: 2 to 3 feet; height of flower spike varies dependent upon cultivar selection and may be between 2 to 6 feet tall

Spread: 1 to 3 feet; dependent upon cultivar selection

Plant habit: upright

Plant density: moderate

Growth rate: moderate

Texture: medium

Foliage

Leaf arrangement: alternate

Leaf type: simple

Leaf margin: entire

Leaf shape: linear

Leaf venation: parallel

Leaf type and persistence: evergreen

Leaf blade length: 8 to 24 inches

Leaf color: green

Fall color: no fall color change

Fall characteristic: not showy

Flower

Flower color: blue; lavender; purple; white; bicolor; dependent upon cultivar selection

Flower characteristic: summer-flowering; showy

Fruit

Fruit shape: three-sided capsule

Fruit length: less than 1 inch

Fruit cover: capsule

Fruit color: brown

Fruit characteristic: showy seed pods

Trunk and Branches

Trunk/bark/branches: not applicable

Current year stem/twig color: not applicable

Current year stem/twig thickness: not applicable

Culture

Light requirement: plant grows in full sun, plant grows in partial shade

Soil tolerances: occasionally wet; slightly alkaline; acidic; clay; sand; loam

Drought tolerance: moderate

Soil salt tolerance: unknown

Plant spacing: 18 to 24 inches

Other

Roots: not applicable

Winter interest: no special winter interest

Pest resistance: no serious pests are normally seen on the plant

Toxicity: this plant exhibits low toxicity; ingesting and handling the sap may cause dermatitis

Use and Management

Agapanthus grows and flowers best when planted in full sun but may also be located in partial shade. Bloom quantity is decreased when Agapanthus does not receive at least 6 to 8 hours of direct sun daily; however, the plant may benefit from more shade when located in the southern range of its planting zone. Agapanthus tolerates a variety of soil conditions, preferring moist well-drained organic soil conditions. Overwatering and overfertilization of this plant will decrease the flowering and overall appearance. This plant will form a large clump, making an attractive groundcover or accent plant. Plant about 18 to 24 inches apart for a thick groundcover effect. Proper spacing promotes plant health and helps the plant avoid disease issues. This plant may also be used in a container or above-ground planter, or as a houseplant.

Propagation is by division or seed.

Design Considerations

Pair with plants that feature fine or contrasting foliage and mounding or spreading forms. Companion plants with dark green or burgundy leaves will emphasize the blue flower clusters and the soft green tones of the leaves. New agapanthus cultivars also have white, dark blue, and violet-blue flowers. When pairing with other flowering plants use white, or warm colors such as pinks, corals, soft yellows, and light orange with the blue-flowered agapanthus. The white-flowered variety can be used with any other color to brighten the space.

Pests and Diseases

Pest issues include chewing insects, maggots, snails, and borers. Disease issues include Botrytis (this can devastate a planting, especially in humid climates in the eastern US; disease-resistant selections should be utilized in this area).