Agapanthus Not Flowering: Top Causes and Solutions

  • By: Michael Barnes
  • Time to read: 9 min.

Are your agapanthus plants not flowering as expected? Understanding the common causes and finding the right solutions can help bring the beautiful blooms back to your garden. When your agapanthus refuses to show off its stunning flowers, several factors like insufficient sunlight, improper watering, or lack of nutrients might be the culprit.

To ensure the success of your agapanthus flowers, you need to provide them with the right growing conditions. One potential reason for a lack of blooms is not enough sunlight, as they require at least six hours of sun exposure per day. Make sure your agapanthus plants have ample access to sunlight, but keep in mind they might benefit from partial shade during peak afternoon hours if you live in a very hot climate.

Another factor impacting flowering is the quality of the soil and proper fertilization. Agapanthus plants thrive when fertilized with a mix of phosphorus and low nitrogen. Fertilizing your plants twice a year will help improve their overall health and encourage successful blooming. Monitoring watering needs and protecting them from frost damage will also be essential to achieving those gorgeous agapanthus flowers in your garden.

Why Agapanthus May Not Flower

Not Enough Sunlight

Agapanthus requires plenty of sunlight to bloom properly. If your agapanthus is not flowering, it could be due to a lack of light, especially if it’s placed in a shady area. To encourage blooming, make sure your agapanthus plant is placed in an area that receives at least 6 hours of full sun daily.

Drought or Watering Issues

Another common reason for agapanthus not flowering is inconsistent watering or drought conditions. These plants prefer evenly moist soil, especially during the growing season. Keep a close eye on your plant’s water needs to avoid underwatering or overwatering. A balanced watering schedule can help prevent issues and promote healthy blooming.

Nitrogen Overload

Too much nitrogen in the soil can lead to a lack of flowering in agapanthus plants. Excessive nitrogen encourages leaf growth at the expense of blooms. If you suspect nitrogen overload, reduce your use of high-nitrogen fertilizers, or use a blooming plant fertilizer during the spring months.

Root Crowding

Mature agapanthus plants may become root-bound or crowded, limiting their ability to bloom. If your plant is mature and not flowering, consider dividing and replanting it in a larger space. This will allow the roots to expand, promoting healthy growth and flowering in the coming seasons.

First Year or Transplant Shock

Transplant shock and first-year blooms can be tricky for agapanthus plants. If you’ve recently planted or transplanted your agapanthus, it may need some time to adjust to its new environment before it begins flowering. Be patient, as it may take a full season for the plant to recover and start blooming.

Frost Damage

Lastly, your agapanthus not flowering could be due to frost damage. Frost damage can lead to poor flower quality or even cause the flower buds to die. Protect agapanthus plants from potential frost damage by providing adequate shelter or mulching the base during late summer and the colder months.

Agapanthus Not Flowering

Growing Conditions for Agapanthus

Sun Exposure

Agapanthus plants require at least six hours of sunlight per day to produce blooms. They thrive in full sun, but in very hot climates, they may benefit from shade during the peak of the afternoon. If your agapanthus is not flowering, check whether it is receiving enough sun exposure and consider moving it to a sunnier location if necessary.

Watering Needs

Your agapanthus needs consistent watering to grow and bloom properly. However, it is important to avoid overwatering, as these plants prefer well-draining soil conditions. Overwatering can cause the roots to rot, which will negatively affect its flowering ability. Ensure you are providing your agapanthus with the right amount of water while avoiding soggy soil conditions.

Soil Requirements

To achieve optimal growth and blooming, agapanthus plants require a well-draining soil that is rich in nutrients such as phosphorus and potassium. Fertilize your agapanthus during its growing season with a balanced fertilizer to ensure it gets the necessary nutrients for healthy growth and flowering. It is also important to note that these plants can withstand cold temperatures but may suffer from frost damage on their flower buds. Choose a cold-hardy variety if you live in a region with harsh winters to help your agapanthus bloom successfully.

Feeding and Fertilizing Agapanthus

Fertilizer Types

To encourage your agapanthus to produce healthy blooms, it’s essential to provide the right nutrients through proper feeding and fertilizing. Choose a balanced fertilizer with a slightly higher phosphorus content, such as 10-10-10 or 5-5-5.

Avoid high nitrogen fertilizers, as they can promote leafy growth instead of flowering. Instead, consider using a high potash fertilizer to support the blooming process. High potash fertilizers are known for promoting flower production and overall plant health.

Feeding Schedule

Consistent feeding is necessary for agapanthus to thrive and produce vibrant blooms. Start by feeding your agapanthus plant twice monthly during springtime, using a water-soluble fertilizer for blooming plants recommended by experts.

As the plant begins to bloom, reduce the feeding frequency to once monthly. It’s essential to stop fertilizing your agapanthus when the blooming ceases, typically in early autumn.

Keep in mind that agapanthus requires sufficient sunlight to bloom. Ensure your plant receives enough light throughout the growing season, as lack of sunlight can hinder flower production. By adhering to these fertilization and feeding practices, you will create an environment in which your agapanthus can flourish and produce stunning blooms.

Container Gardening for Agapanthus

Pot Size and Drainage

When planting agapanthus in containers, it’s essential to choose the right pot size to ensure the plant’s optimal growth. Agapanthus generally grows to between 18 inches to four feet tall and one to three feet wide, depending on the cultivar. For a single, large plant, or two to three smaller, younger ones, select a container that’s at least 12 inches in diameter and eight to 12 inches deep.

Having appropriate drainage in your container is equally crucial. Make sure the selected pot has drainage holes. Fill the container with a lightly moistened mix of compost or potting soil and sand or grit for drainage. This combination will help avoid waterlogging, allowing your agapanthus plant to thrive (source).

Agapanthus prefers a sunny location, but it can tolerate partial shade. However, placing your container in full sun will result in more abundant blooming. Remember to water and fertilize your agapanthus regularly. Use a water-soluble fertilizer for blooming plants, applying it twice monthly during spring and reducing it to once a month when the plant begins to bloom.

Dividing Agapanthus

Dividing agapanthus is an important maintenance task to encourage more blooms and controlled growth. This should be done once the plant has finished flowering.

Here are the steps to divide your agapanthus:

  1. Carefully remove the plant from its container.
  2. Use a sharp knife or a pair of shears to divide the root ball into two or three sections.
  3. Replant each division into a separate pot, placing the roots one inch deep and spaced 12 inches apart (source).

Keep in mind that the divisions may not flower immediately after being separated. They may take up to a year to produce new blooms. With proper care and attention, your container-grown agapanthus will add a stunning display to your garden.

Agapanthus Not Flowering

Common Pests and Diseases

Identifying Issues

Agapanthus plants may face a variety of pests and diseases that can impede their flowering process. Common pests include aphids, caterpillars, slugs, snails, and nematodes, which can cause damage to the plant and hinder flower bud development.

Diseases, such as powdery mildew, root and bulb rot, and rhizoctonia, can negatively impact the health of your agapanthus plants. In particular, diseases like leaf spot can reduce their overall performance and appearance.


To prevent these common issues, it’s crucial to provide your agapanthus plants with proper care and maintenance. Some measures you can take include:

  • Ensuring optimal growing conditions by providing sufficient sunlight (at least six hours per day) and well-draining soil.
  • Regularly checking plants for signs of pests or diseases, and taking prompt action if any are detected.
  • Maintaining a layer of mulch around the plants to help retain moisture and suppress weeds that can harbor pests.


If you encounter any pests or diseases affecting your agapanthus plants, it’s essential to identify the problem accurately and use appropriate treatment methods. Some recommended treatments include:

  • For pests such as aphids, caterpillars, and thrips – remove them manually, or use non-toxic methods like water jet or neem oil.
  • For slugs and snails – use mechanical barriers like copper tape or create a natural barrier with crushed eggshells or coffee grounds.
  • For diseases like root rot and bulb rot – improve soil drainage, and avoid overwatering, as these conditions can make plants more susceptible to disease. According to Plantgardener, proper drainage helps prevent fungal issues that can impact flowering.
  • For fungal diseases like powdery mildew and leaf spot – apply appropriate fungicides, but remember to read the label instructions carefully and follow the recommended guidelines.

By closely monitoring your agapanthus plants for common pests and diseases and applying the right treatment when required, your agapanthus should continue to thrive and produce beautiful flowers.

Protecting Agapanthus in Winter

Cold Weather Care

Agapanthus, also known as Lily of the Nile, is a South African plant known for its striking blooms. Due to its origins, it is only hardy to USDA hardiness zones 9 to 11, so providing protection during winter is crucial for its survival in colder climates. Firstly, examine your plant’s location. Agapanthus requires at least 6 hours of full sun per day and well-draining soil to avoid boggy conditions.

During winter, keep an eye out for frost damage on your Agapanthus, as temperatures below freezing can harm the plant. The deciduous varieties cope better in colder conditions since they naturally go dormant in winter, but their ideal temperature range is still between 40 and 50°F.

Overwintering Options

  1. Cold Greenhouse: If you have a cold greenhouse, it can be an excellent option for protecting your Agapanthus in winter. The controlled environment provides a steady temperature and shields the plant from harsh weather conditions. Ensure that the greenhouse maintains an appropriate temperature range for your Agapanthus variety.
  2. Garage or Basement: In colder regions, you may need to bring your Agapanthus indoors during winter. A garage or basement can provide a suitable environment for overwintering. A temperature of 40-50°F is ideal for deciduous varieties. If you keep the plant in your basement, consider using fluorescent bulbs close to the plants for about 16 hours per day to provide some light.

In conclusion, protecting your Agapanthus during winter is essential to ensure its survival in colder climates. Assess the plant’s location, ensure proper care, and use suitable overwintering options like a cold greenhouse or a garage to keep your Agapanthus thriving and blooming the following season.

Additional Agapanthus Tips


To encourage more blue flowers on your agapanthus, practice regular deadheading. This process involves removing spent flowers to refocus the plant’s energy on producing new blooms. Simply trim off the faded flower heads, cutting back to the base of the flower stem. This will help your African Lily stay healthy and keep your garden looking neat.

Timing Blooms

Agapanthus, also known as Lily of the Nile, is primarily a summer-flowering perennial plant. However, different varieties can have varying bloom times. To ensure a consistent display of blooms throughout the season, consider planting a mix of early, mid, and late-season flowering agapanthus. You should also provide your plant with at least six hours of direct sunlight each day to keep the flowers coming.

Choosing the Right Variety

When selecting the perfect agapanthus variety for your garden, consider factors such as climate, soil type, and available space. Agapanthus can thrive in a range of climates, but some varieties are more cold-hardy than others. Be sure to choose a type that’s suitable for your location and can withstand local winter temperatures.

Regarding soil, agapanthus can perform well in various types, but they prefer well-draining, fertile soil. If you have heavy clay soil, consider amending it with organic matter to improve drainage for your plants. Additionally, there are both evergreen and deciduous varieties of agapanthus; consult your local garden centre for advice on the best choice for your specific garden conditions.

Finally, don’t forget to consider the size of your garden when choosing the right variety. Different agapanthus types can range from compact to large-size plants, and selecting the appropriate one will ensure your garden stays neat and cohesive.

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