Gardening Plants & Flowers Flowers

How to Plant, Grow and Care for Agapanthus

Front view of purple agapanthus Lily of the Nile flowers

The Spruce / Evgeniya Vlasova

Agapanthus is a genus of six species of perennial plants with bell-shaped vibrant flowers. They tend to bloom from early summer until fall in shades of blue, pink, purple, and white often with a darker center stripe on each petal. Flowers bloom on tall stalks, and leaves spread out wide and long from the base. The leaves can be evergreen or deciduous depending on the variety and dark to light green, gray-green, or blue-green in color.

Agapanthus blooms attract hummingbirds, are excellent cut flowers and many are deer and rabbit resistant. Agapanthus is toxic for both humans and pets.

Common Name African lily, Lily-of-the-Nile
Botanical Name Agapanthus
Family Agapanthaceae
Plant Type Herbaceous perennial
Mature Size 3 ft. tall, 2 ft. wide
Sun Exposure Full sun, part shade
Soil Type Sandy loam, well-drained
Soil pH 5.5 to 7.5
Bloom Time June, July, August, September
Hardiness Zones 7-10 (USDA)
Native Area South Africa
Toxicity Toxic to humans and pets

Agapanthus Care

How you care for your agapanthus differs depending on whether the species or hybrid is evergreen or deciduous. The biggest maintenance concern is how to protect your agapanthus during winter. Evergreen types are much more sensitive to cold temperatures. Deciduous varieties can withstand occasional light frost but frozen ground can damage the base of the plant.

Agapanthus can be grown in most USDA zones, however, evergreen species are less hardy in USDA hardiness zones 7 through 10 and might require winter protection. In Northern zones, you can dig up the rhizomes of deciduous perennial varieties in the fall and store them or plant them in pots for the spring.

Closeup of purple agapanthus Lily of the Nile flowers

The Spruce / Evgeniya Vlasova

Macro closeup of purple agapanthus Lily of the Nile flower blooms

The Spruce / Evgeniya Vlasova

Macro closeup of a purple agapanthus Lily of the Nile bud unfurling

The Spruce / Evgeniya Vlasova

Closeup side angle of purple agapanthus Lily of the Nile flowers

The Spruce / Evgeniya Vlasova

Planting

Because agapanthus needs protection from cold temperatures, when and how you plant it depends on the species you have and where you live.

In USDA hardiness zones 9 and 10 plant agapanthus in the ground in autumn. In zones 7 and lower, plant in spring when soil temperatures reach 50 degrees Fahrenheit. Place the rhizomes two inches deep and 12 to 18 inches apart. The pointed end faces upward. Add a heavy layer of mulch for cold weather protection.

If you're growing agapanthus in pots, plant rhizomes in spring, 1 inch deep and 8 inches apart. Use a fertile, well-draining potting mix and a container with drainage holes. A 12-inch diameter pot is the right size to accommodate one plant, but plants bloom best when they are pot-bound.

Light

Agapanthus requires full sun, six to eight hours daily, to produce better blooms. In hot climates, plants benefit from afternoon shade.

Soil

Agapanthus is tolerant of soil type but grows best in fertile, light, sandy loam with good drainage. Agapanthus africanus prefers slightly acidic soil with a pH between 5.5 to 6.5 but other species grow well in a neutral soil pH of 7.0.

Water

Water regularly to provide 1 inch per week until plants are established, then reduce the amount to 1/2 inch per week. Agapanthus are drought resistant and won't tolerate standing water. Significantly reduce or eliminate watering in winter until new growth begins the following spring.

Temperature and Humidity

Ideal temperatures range from 50 to 60 degrees Fahrenheit. Some species tolerate temperatures as low as 20 degrees Fahrenheit. but many evergreen types should be brought indoors when temperatures reach an average of 50 degrees.

Thinning plants for good air circulation, in areas with high humidity, cuts down on fungal problems.

Fertilizer

Add a balanced fertilizer once in spring and again two months later. Or choose a fertilizer with the NPK slightly higher in phosphorous such as a 5-10-10 ratio. Feeding with too much nitrogen can reduce blooms or cause flower stems to fail to reach their full height. Do not fertilize after August.

Types of Agapanthus

The six species of agapanthus are native to South Africa and have not been found growing naturally anywhere else across the globe. All species hybridize easily and are not yet fully classified, however, numerous subspecies and cultivars exist. Here are a few of the most popular and common types grown domestically.

  • Agapanthus africanus 'Arctic Star': A semi-evergreen early bloomer, this cultivar produces large clusters of trumpet-shaped white flowers. 'Arctic Star' is one of the hardiest cultivars, surviving temperatures below freezing.
  • Agapanthus africanus 'Bressingham Blue': A deciduous type with large flower clusters four and a half inches across bearing amethyst blue flowers with a dark blue stripe. Flowers appear in mid to late summer on three-foot stalks.
  • Agapanthus praecox ssp. orientalis 'Queen Mum': This evergreen cultivar blooms early to mid-summer with white and violet-blue clusters of flowers on stalks up to four feet tall.
  • Agapanthus campanulatus var. patens F2 hybrid 'Brilliant Blue': A dwarf cultivar growing to just two feet tall and wide, this African lily blooms in August bearing clusters of rich blue flowers with a dark purple stripe.

Pruning

Once flowers fade, remove the entire stem to promote repeat blooming. Remove dead or damaged foliage at any time but avoid cutting back foliage from deciduous types after blooming. Leaves feed the rhizome which stores energy for next year's bloom so let them die back naturally. The leaves of evergreen varieties can be trimmed to six to eight inches to ease division and planting in containers.

Propagating Agapanthus

Agapanthus is easily and most reliably propagated by division. Garden-grown plants should be divided every four to six years. Potted plants bloom better when root-bound and a good rule of thumb is to divide and re-pot every four to five years. Division is accomplished best in early spring for deciduous plants and in autumn after blooming for evergreen varieties.

Warning

Agapanthus hybridizes easily and new varieties become available often. If you purchase a patented hybrid plant it is illegal to propagate it. Check the label for the phrase "patent pending" or ask the grower or re-seller.

Tools you need to divide agapanthus include a shovel, hand shears, a sharp knife, and gloves.

  1. Choose a clump of agapanthus and use shears to cut foliage down to six to eight inches for easier handling.
  2. Use the shovel to dig around the clump 6 inches from the center and eight inches deep
  3. Lift the clump and shake soil from the roots, removing as much as you can.
  4. Grasp 1/2 of the clump at the base in each hand and gently pull apart the plants and attached roots. They should separate easily. If necessary, use a sharp knife to cut through the bottom of the root ball to separate plants.
  5. Divided plants that were difficult to divide should be cured to heal over for several days before replanting. Plants that divide easily can be immediately replanted in a new location in the garden.
  6. Dig a new hole, wide and deep enough to accommodate plant roots, Place each division 12 to 18 inches apart.
  7. Withhold water for several days to allow plants to settle.

Tips for Dividing Potted Agapanthus

To remove agapanthus from its container, loosen the soil around the container edges, then turn the pot on its side, grasp the base of the clump, and slide it out. Newly divided plants can be repotted in 12-inch containers filled with a slightly moistened, well-draining potting medium. A good mix is soil or compost blended with grit or coarse sand for improved drainage.

How to Grow Agapanthus From Seed

Seeds are easily collected from dry brown pods that mature in late summer and early autumn. The seeds are short-lived, so sow them immediately. Note that collected seeds might not produce plants identical to the original. Agapanthus seeds are also available for purchase. Plants grown from seed can take three to five years to produce flowers. To propagate from seed, gather seed trays, and seed starting medium.

  1. Fill seed trays with a moistened, well-draining seed starting medium.
  2. Soak seeds for several hours before planting. (This step is optional; soaking speeds up germination slightly.)
  3. Place seeds on top of the medium and cover lightly with medium or grit. Agapanthus seeds need exposure to light for germination.
  4. Water lightly and place in a sunny location with temperatures between 68 and 86 degrees Fahrenheit.
  5. Keep soil moist but not wet.
  6. Germination occurs in about one month. Move sprouts to a cooler location (around 58 degrees Fahrenheit) but maintain bright light.
  7. Once the root structure is well-developed pot up into 12-inch pots or plant out in the garden after the final frost.

Potting and Repotting Agapanthus

Agapanthus grows well in pots and blooms best when root bound. Individual plants should be potted up into containers four inches wider every two years to accommodate spread. A 12-inch pot will hold one agapanthus plant. Plants in 24-inch containers can be grown out until blooms start to diminish, then should be divided.

Here's how to grow agapanthus in a pot:

  1. Choose a container 12 inches wide with drainage holes. It will do well in pots that are clay, ceramic, or plastic.
  2. Fill the container with a lightly moistened mix of compost or potting soil and sand or grit for drainage.
  3. Make a shallow depression in the center of the pot. Plant rhizomes 1 inch deep with the pointed end up and cover with potting medium.
  4. Remove a purchased plant from its original container and place it in the pot at the same level.
  5. Place the pot in indirect sunlight and withhold water for several days to allow the plant to acclimate.
  6. Move the pot into a sunnier spot and add 1 inch of water per week until the plant is well established. Then reduce water to 1/2 inch per week.

Overwintering

Agapanthus are tough plants but winter hardiness is a challenge, so it's important to verify the cold hardiness of your plants, Evergreen agapanthus is unlikely to tolerate cold winter weather and should be either heavily mulched or grown in pots and moved indoors for overwintering. It's best not to overwinter them outdoors unless you live in USDA hardiness zones 9 and 10.

Deciduous, semi-evergreen, and half-hardy varieties have different degrees of cold tolerance. Deciduous agapanthus is considered half-hardy to USDA zone 6 but some hybrids might keep their leaves through winter if there's not much frost. Rhizomes can be lifted in autumn after leaves die back, stored, and replanted in spring. Add heavy mulch to plants grown in the garden or move potted plants to a sheltered location. Water is reduced or withheld during winter months.

To store agapanthus tubers, let them cure for several days to dry. Then wrap them in newspaper and store in a cool, dark location. The ideal storage temperature is 40 to 50 degrees Fahrenheit.

Common Pest & Plant Diseases

Agapanthus are seldom bothered by insects but can attract aphids, mealy bugs, and red spider mites. A strong spray with a hose can knock them off the plant. Treat severe infestations with horticultural or neem oil.

Fungal diseases like verticillium wilt can affect overcrowded plants. Pot up and divide plants regularly to allow for good air circulation.

How to Get Agapanthus to Bloom

Failure to bloom is attributed to cold weather, lack of winter protection, and inadequate light. Agapanthus blooms best with six to eight hours of sunlight daily. Provide winter protection with mulch and move potted plants indoors or into a sheltered location. Feed agapanthus in spring with a fertilizer higher in phosphorous and feed again mid-season.

Common Problems With Agapanthus

Yellowing Leaves

The leaves of evergreen varieties can turn yellow at the end of the growing season. This is a natural process of older foliage dying back and it can be removed. New leaves will grow from the center to replace the dying foliage.

Reduced Blooms

Reduced blooms can indicate that the plants need to be divided. Replant the newest growth and discard older plants from the center of the clump.

FAQ
  • Is agapanthus a perennial or annual?

    Agapanthus is a perennial plant that grows best in areas with mild winters. Like other tender bulbs, in colder growing zones, the rhizomes of deciduous plants can be lifted and stored in autumn to replant in spring. Both deciduous and evergreen varieties can be overwintered in pots indoors or in a protected location.

  • Should agapanthus be cut back?

    Remove flower stems after flowers fade but retain foliage until deciduous types die back naturally. Dead or damaged leaves can be removed from both deciduous and evergreen types at any time. For dividing or potting up, evergreen leaves can be cut back to six to eight inches long.

  • How does Agapanthus spread?

    Agapanthus can reseed but spread is more likely to occur by rhizome in most growing zones.

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