How to Sow

Planting Bare Root Plants:

• Choose a location in full sun with a rich, well-drained soil.
• Prepare the bed by turning the soil under to a depth of 6-12 inches removing any debris, and lightly raking as level as possible.
• The addition of organic matter (leaf mold, compost, well-rotted manure) benefits all gardens and is essential in recently constructed neighborhoods.
• Dig a hole deep and wide enough to accommodate the bare root.
• Plant them so the tops of the roots are just below the surface.
• Fill in and around the root with soil until the hole is filled.
• Firm the soil and water well to fully saturate the roots and soil.
• Space agapanthus about 24 inches apart.

Planting Plotted Plants in the Garden:

• Select a location in full sun with good rich moist organic soil. 
• Prepare the bed by turning the soil under to a depth of 6-12 inches removing any debris, and lightly raking as level as possible.
• The addition of organic matter (leaf mold, compost, well-rotted manure) benefits all gardens and is essential in recently constructed neighborhoods.
• Plant on a cloudy day or in late afternoon to reduce transplant shock.
• Dig a hole for each plant large enough to amply accommodate the root ball. 
• Unpot the plant and gently loosen the root ball with your hands to encourage good root growth. 
• Place the top of the root ball even with the level of the surrounding soil. Fill with soil to the top of the root ball. Press soil down firmly with your hand. 
• Use the plant tag as a location marker. 
• Thoroughly water and apply a light mulch layer on top of the soil (1-2 inches) to conserve water and reduce weeds.
• Space agapanthus plants 24 inches apart.

How to Grow

• Keep weeds under control during the growing season. Weeds compete with plants for water, space and nutrients, so control them by either cultivating often or use a mulch to prevent their germination. 
• Mulches also help retain soil moisture and maintain even soil temperatures. For perennials, an organic mulch of aged bark or shredded leaves lends a natural look to the bed and will improve the soil as it breaks down in time. Always keep mulches off a plant’s stems to prevent possible rot.
• Careful watering is essential in getting perennials off to a good start. Water thoroughly at least once a week to help new roots grow down deeply. Soil should be damp at about 1 inch below the soil surface. You can check this by sticking your finger in the soil. Water early in the morning to give all leaves enough time to dry. One inch of rain or watering per week is recommended for most perennial plants. You can check to see if you need to add water by using a rain gauge.
• Until plants become established, some protection from extreme winds and direct, hot sunlight may be necessary. Good air movement is also important.
• After new growth appears, a light fertilizer may be applied. Keep granular fertilizers away from the plant crown and foliage to avoid burn injury. Use low rates of a slow release fertilizer, higher rates may encourage root rots. Do not fertilizer in the fall.
• Remove and discard foliage after a hard frost in fall
• Evergreen boughs (from Christmas trees) provide additional protection. Remove this mulch in the spring.
• In general agapanthus do not require division. They blossom more freely when crowded, their roots should be disturbed as little as possible.

Growing Tips

• Agapanthus make wonderful, long lasting cut flowers.
• Agapanthus blooms form mid-summer to early fall

Common Disease Problems

Anthracnose: This is a fungus disease causes brown spots with purple edges on the leaves. The spots turn black in the center; leaves become yellow, dry and fall off. The fungus overwinters in diseased plant debris. Burpee Recommends: Avoid overhead watering which can spread the fungus spores. Keep a clean garden, remove and discard all diseased plant material. Use a mulch to prevent spores from splashing from the soil onto plants.

Botrytis: This fungus causes a grey mold on flowers, leaves, stems and buds. It thrives in cool wet weather conditions. Burpee Recommends: Remove affected plant parts, avoid watering at night and getting water on the plant when watering. Make sure plants have good air circulation. Contact your Cooperative Extension Service for fungicide recommendations.

Powdery Mildew: This fungus disease occurs on the top of the leaves in humid weather conditions. The leaves appear to have a whitish or greyish surface and may curl. Usually occurs if agapanthus is grown in a shady area. Burpee Recommends: Avoid powdery mildew by providing good air circulation for the plants by good spacing and pruning. Contact your Cooperative Extension Service for fungicide recommendations.

Root Rots: A number of pathogens cause root rots. Burpee Recommends: Practice crop rotation and do not plant related crops in the same area for several years. Pull up and discard infected plants. Make sure your soil has excellent drainage. Contact your Cooperative Extension Service for recommendations.

Common Pest and Cultural Problems

Mealybugs: Mealybugs are 1/8 to ¼ inch long flat wingless insects that secrete a white powder that forms a waxy shell that protects them. They form cottony looking masses on stems, branches and leaves. They suck the juices from leaves and stems and cause weak growth. They also attract ants with the honeydew they excrete, and the honeydew can grow a black sooty mold on it as well. Burpee Recommends: Wash affected plant parts and try to rub the bugs off. They may also be controlled by predator insects such as lacewings, ladybugs and parasitic wasps. Check with your Cooperative Extension Service for pesticide recommendations.

Slugs: These pests leave large holes in the foliage or eat leaves entirely. They leave a slime trail, feed at night and are mostly a problem in damp weather. Burpee Recommends: Hand pick, at night if possible. You can try attracting the slugs to traps either using cornmeal or beer. For a beer trap, dig a hole in the ground and place a large cup or bowl into the hole; use something that has steep sides so that the slugs can’t crawl back out when they’re finished. Fill the bowl about ¾ of the way full with beer, and let it sit overnight. In the morning, the bowl should be full of drowned slugs that can be dumped out for the birds to eat. For a cornmeal trap, put a tablespoon or two of cornmeal in a jar and put it on its side near the plants. Slugs are attracted to the scent but they cannot digest it and it will kill them. You can also try placing a barrier around your plants of diatomaceous earth or even coffee grounds. They cannot crawl over these.

Spider Mites: These tiny spider-like pests are about the size of a grain of pepper. They may be red, black, brown or yellow. They suck on the plant juices removing chlorophyll and injecting toxins which cause white dots on the foliage. There is often webbing visible on the plant. They cause the foliage to turn yellow and become dry and stippled. They multiply quickly and thrive in dry conditions. Burpee Recommends: Spider mites may be controlled with a forceful spray every other day. Try hot pepper wax or insecticidal soap. Check with your Cooperative Extension Service for miticide recommendations.

Thrips: Thrips are tiny needle-thin insects that are black or straw colored. They suck the juices of plants and attack flower petals, leaves and stems. The plant will have a stippling, discolored flecking or silvering of the leaf surface. Thrips can spread many diseases from plant to plant. Burpee Recommends: Many thrips may be repelled by sheets of aluminum foil spread between rows of plants. Remove weeds from the bed and remove debris from the bed after frost. Check with your Cooperative Extension Service for pest controls.

FAQ

Can I grow agapanthus in containers? Yes, they tend to like their roots to be crowded, so when they become potbound only move them up one size.

Why didn’t my agapanthus flower? Agapanthus is sensitive to drought conditions after it has finish flowering. To ensure a good display next year, keep plants moist until autumn after flowers start to fade, which will encourage the development of new flower buds. Too much shade or not enough winter protection can also cause agapanthus not to flower.