With their brightly colored blooms borne on tall stems above attractive strappy foliage it’s no wonder agapanthus are such popular garden plants. Also known as Lily of the Nile or African Lily, agapanthus add height texture and plenty of visual interest to both beds and containers. But just how tall can these beauties get?
The mature height of your agapanthus depends on several key factors. By understanding what conditions promote vertical growth you can tailor your care to achieve your desired plant height.
Typical Agapanthus Heights
Most agapanthus varieties reach maturity at 2 to 4 feet tall. Dwarf types may stay under 2 feet, while larger varieties can exceed 4 feet.
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Dwarf agapanthus – Under 2 feet
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Medium varieties – 2 to 3 feet
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Tall varieties – 3 to 4 feet
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Extra tall varieties – Over 4 feet
Mature spread is usually about 2/3 to equal the height. So a 3 foot tall plant will be around 2 to 3 feet wide at its base.
These heights assume ideal growing conditions. Insufficient light, nutrients or water can result in plants that fail to reach their maximum potential height.
Factors That Increase Height
Several key factors influence vertical growth and determine whether your agapanthus reaches the upper end of its expected mature height range:
Sunlight
Agapanthus thrive in full sun. At least 6 hours of direct sun per day results in the tallest growth. Insufficient sunlight causes lanky, leggy growth as plants stretch to reach the light.
Soil Quality
Rich, nutrient-dense soil fuels strong vigorous growth. Amend soil with compost or organic material to provide nutrients. Proper drainage is also vital to prevent stunted plants.
Available Moisture
Consistent deep watering encourages healthy root and plant growth. Allow soil to dry between waterings but don’t let plants wilt severely.
Fertilizer
Apply a balanced fertilizer every few weeks during the active growing season. Nitrogen promotes leafy growth while potassium fuels blooms.
Maturity
Given ideal care, agapanthus gain height each year. Maximum height is reached between 3-5 years from planting.
Genetics
Some varieties are genetically predisposed to be taller, while dwarf types top out at short heights. Select varieties suited to your space.
Factors That Limit Height
On the flip side, the following factors can restrict vertical growth resulting in shorter agapanthus:
Insufficient Sunlight
Too much shade leads to stunted, leggy growth as plants reach for sunlight. At least 6 hours of sun is ideal.
Poor Soil Quality
Nutrient deficiencies, overly sandy or clay soil, improper pH, or poor drainage can all limit growth potential.
Underwatering
Allowing plants to wilt severely during droughts or dry spells inhibits growth. Strive for consistent soil moisture.
Overcrowding
Congested, crowded planting areas restrict air flow and limit access to light and soil resources. Space plants appropriately.
Exposure to Cold
If winters are very cold, the roots can suffer damage resulting in reduced growth the following season. Protect or mulch roots in winter.
Diseases & Pests
Insect, disease or nematode damage stresses plants, redirecting energy away from growth. Keep plants healthy.
Excess Shade
Too little sunlight results in weak, lanky growth as plants stretch for light. Minimum 6 hours of sun is recommended.
Improper Pruning
Cutting back healthy foliage or removing too much of the plant can limit regrowth. Prune judiciously.
Achieving Your Ideal Plant Height
Follow these tips tailor your agapanthus’ growth to achieve the height you desire:
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For taller plants, provide full sun, fertile soil, ample water, and regular fertilizer. Allow plants time to mature.
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For shorter plants, limit fertilizer, prune judiciously, and give less water. Some shade can restrict height.
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Control height with container size. Dwarf types in small pots will stay petite. Plant in-ground for maximum height.
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Choose genetically smaller varieties labeled dwarf, mini, or compact if you need a shorter plant.
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Cut flower stalks once finished blooming to channel energy back to the plant instead of seed production.
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Staking tall varieties keeps them upright instead of sprawling and visually shorter.
Height Based on Variety
There is a diverse range of agapanthus varieties available, which naturally vary in their height potential:
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‘Peter Pan’ – A dwarf variety under 2 feet tall perfect for containers.
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‘Tinkerbell’ – Another compact dwarf type, reaching just 16 inches tall.
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‘Lilliput’ – A mini agapanthus staying under 2 feet even at maturity.
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‘Snow Candle’ – A mid-sized variety that remains 2 to 3 feet tall.
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‘Big Blue’ – Aptly named variety that can exceed 4 feet tall at maturity.
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‘Giant Fireworks’ – A large, bold variety known to reach up to 5 feet tall.
No matter if you want tall, imposing agapanthus or petite, compact plants, there’s a variety tailored to give you the perfect height for your space and needs.
Tips For Managing Tall Agapanthus
If your agapanthus are growing larger than you expected, here are some strategies to keep them in check:
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Prune flower stalks immediately after blooming finishes to direct energy to roots and foliage instead of upward growth.
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Selectively remove some healthy inner foliage in spring to open up the plant’s center and visually reduce its size. Never prune all leaves.
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Transplant overly large in-ground plants into containers. The restricted space helps dwarf their growth.
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Divide congested clumps in early fall to rejuvenate plants and control spread. Replant divisions or gift extras.
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Cut entire plants back halfway in early spring every 2-3 years. New compact growth will emerge and rejuvenate plants.
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Monitor soil moisture closely. Allow roots to slightly dry out between waterings to discourage excessive growth.
The impressive height of agapanthus is part of their ornamental appeal, but that growth potential does require some management in smaller spaces. Follow these tips to find the perfect balance in your garden.
Common Height-Related Questions
How tall do agapanthus get?
Most agapanthus varieties grow 2 to 4 feet tall at maturity. Dwarf types grow under 2 feet while extra large varieties may exceed 4 feet.
How tall do agapanthus grow each year?
Given ideal conditions, agapanthus may grow over 1 foot per year, gaining height steadily until reaching maturity around years 3-5. Growth then slows.
How can I keep my agapanthus from getting too tall?
To limit height, prune spent blooms, restrict fertilizer, allow soil to partially dry between waterings, and plant in part shade instead of full sun. Dwarf varieties also stay short.
Should I cut back tall agapanthus?
You can cut back overly tall plants in early spring, removing about half the foliage. New compact growth will emerge and plants will be smaller. Never prune all leaves.
What is the shortest agapanthus variety?
The dwarf ‘Peter Pan’ and ‘Tinkerbell’ varieties are the shortest, topping out around 1 to 2 feet tall. ‘Lilliput’ is another dwarf type that stays compact.
Can I grow agapanthus indoors?
Most agapanthus get too large for indoor growth. However, dwarf potted varieties like ‘Tinkerbell’ and ‘Peter Pan’ can thrive indoors near a bright sunny window provided with a cool winter rest period.
With their statuesque flower scapes towering over attractive straplike foliage, agapanthus lend height and drama to gardens and containers. Understanding their growth habits allows you to make the most of their vertical impact.
Best Fertiliser For Agapanthus
Agapanthus are vigorous plants that require feeding to keep them growing optimally. The Plant Companys Shrub Fertiliser has been blended to give plants the boost they need and then sustained nutrition for the next 12 months. We recommend the fertiliser is applied to the soil surface in spring just as the plants start to grow actively. More importantly, we advise that no fertiliser is placed in the hole at planting, but rather spread around the soil surface so it can wash through the roots as it releases. The Plant Companys Shrub Fertiliser ensures that nutrients remain in the soil around the plant rather than being lost through the soil profile to where the plant cannot reach it. This also applies to plants grown on sandy soils. The Plant Companys Shrub Fertiliser is therefore very environmentally friendly and longer lasting than most other products in the market.
Foliar feeding using a liquid fertiliser can be undertaken if you have time but this is not essential if Shrub Fertiliser has been applied. If you think the plants need an extra boost or have some yellowing, however, a liquid fertiliser application won’t hurt. A great benefit of foliar feeding is that it helps keep the leaves strong and lush.
What Is Causing The Agapanthus Leaves To Yellow?
Leaf yellowing can result from Agapanthus being grown in stagnant soil conditions, too much shade, or where the plants have not been fed for a number of years. A liquid fertiliser can be used to correct issues quickly and should be supported with Shrub Fertiliser during spring.
How tall can a tree grow? – Valentin Hammoudi
FAQ
How do I keep my agapanthus small?
What is the average height of agapanthus?
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Genus Name
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Agapanthus
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Height
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1 to 4 feet
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Width
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1 to 3 feet
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Flower Color
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Blue, White
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Season Features
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Fall Bloom, Summer Bloom
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Should agapanthus be cut back?
Do agapanthus like full sun or shade?