How to Plant, Grow, and Care for Agapanthus

Also known by more common names such as Lily of the Nile and African Lily, agapanthus is a genus of seven species of perennial plants with bell-shaped, vibrant flowers. They are native to South Africa and do well in zones 7 to 10. They tend to bloom for up to six months, 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.

Agapanthus blooms are easy to care for and have a wide array of landscaping uses, from filling garden beds to bordering yards. These plants also attract hummingbirds, are excellent cut flowers, and many are deer and rabbit-resistant. Agapanthus is toxic to both humans and pets.

How to Plant Agapanthus

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

When to Plant

Plant agapanthus in the ground in autumn in USDA hardiness zones 9 and 10. In zones 7 and lower, plant in spring when soil temperatures reach 50 degrees Fahrenheit. If you're growing agapanthus in pots, plant rhizomes in spring,

Where to Plant

Use pots or a garden bed to plant agapanthus. Choose an area in full sun (and that has afternoon shade if you live in a hot climate). Select a spot that also has well-draining soil.

How to Plant

Place the rhizomes two inches deep and 12 to 18 inches apart. Face the pointed end upward. Add a heavy layer of mulch for cold-weather protection. Plant any agapanthus you are growing in pots 1 inch deep and 8 inches apart. Use a fertile, well-draining potting mix and a container with drainage holes. Use a 12-inch diameter pot to accommodate one plant, but note that plants bloom best when they are pot-bound.

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.

• Agapanthus needs six hours of sunlight per day.
• This plant prefers well-draining, fertile, sandy, loamy soil.
• Give agapanthus 1 inch of water per week, reducing it by half once mature.
• Agapanthus’s ideal temperature is between 50 to 60 degrees Fahrenheit; plants can be thinned in high-humidity areas.
• Fertilize in the spring, then again after two months.
• Evergreen types are much more sensitive to cold temperatures, so use weather protection methods.
• Deciduous varieties can withstand occasional light frost, but frozen ground can damage the base of the plant.
  

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 types 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.

Reduce fungal problems by thinning plants to allow for good air circulation, especially in areas with high humidity.

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

There are two main species and seven different types of agapanthus. They are all 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 campanulatusvar. 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 the 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 6 to 8 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 often become available. 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.

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

1. Choose an agapanthus clump and use shears to cut foliage down to 6 to 8 inches.
2. Dig around the clump 6 inches from the center and 8 inches deep.
3. Lift the clump and shake as much soil from the roots 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. Use a sharp knife to cut through the bottom of the root ball to separate plants if needed.
5. Divided plants that were difficult should be cured to heal over for several days before replanting. Plants that divide easily can be immediately replanted.
6. Dig a new hole, wide and deep enough to accommodate plant roots. Place each division 12 to 18 inches apart. Or, repot in 12-inch containers filled with a slightly moistened, well-draining potting medium.
7. Withhold water for several days to allow plants to settle.

How to Grow Agapanthus From Seed

Seeds are easily collected from dry brown pods that mature in late summer and early autumn if you do not want to purchase new ones. The seeds are short-lived, so sow them immediately. Note that collected seeds might not produce plants identical to the original. 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 if you would like to speed up germination.
3. Place seeds on top of the medium and cover lightly with medium or grit.
   
4. Water lightly to keep soil moist (but not wet) and place in a sunny location with temperatures between 68 and 86 degrees Fahrenheit.
5. Germination occurs in about one month. Move sprouts to a cooler location (around 58 degrees Fahrenheit), but maintain bright light.
   
6. Once the root structure is well-developed, place into 12-inch pots or plant 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. Plants in 24-inch containers can be grown out until blooms start to diminish, then should be divided.

To grow agapanthus in a pot, choose a container 12 inches wide with drainage holes. Fill it with a lightly moistened mix of compost or potting soil and sand or grit for drainage. 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. Place the container in indirect sunlight and withhold water for several days to allow the plant to acclimate. 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. 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 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. Water is reduced or withheld during the winter months. To store agapanthus tubers, let them cure for several days to dry. Then wrap them in newspaper and store them in a cool, dark location. Store at 40 to 50 degrees Fahrenheit.

Common Pest & Plant Diseases

Agapanthus are seldom bothered by insects but can attract aphids, mealybugs, 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 midseason.

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.

From: thespruce