Agapanthus: How to Grow Lush, Flowering Lily of the Nile in Australia

Agapanthus are hardy, drought-tolerant perennials famous for their strappy green leaves and bold blue or white globe-like flowers. Whether grown in garden beds or pots, the secret to vigorous blooming is correct fertilisation and trimming. This guide covers everything from planting and pot care to propagation and feeding.

Agapanthus Basics: Growth Habit and Ideal Conditions

Agapanthus thrive across most Australian climates, from coastal Sydney to inland Victoria. Native to South Africa, they’re low-maintenance plants that tolerate heat, poor soils, and dry spells.

Height: 50cm–1.5m depending on cultivar (dwarf or giant)
Flowers: Large umbels in white, lavender, or deep blue
Bloom Time: Late spring to midsummer, with some reblooming into autumn
Light: Full sun to part shade (flowering is best in sun)
Soil: Free-draining soil, pH neutral to slightly acidic (6.0–7.0)

Planting Tips:

Space plants 30–60cm apart to allow clump formation
Plant crowns just below soil surface with roots spread flat
Water in well with diluted CompleteGrow NPK 20-20-20 to reduce transplant shock
Use bark mulch or stones (not compost) to suppress weeds and regulate soil moisture

Agapanthus in Pots: Container Care and Propagation Tips

Agapanthus do well in containers, especially dwarf or compact forms like ‘Baby Pete’ or ‘Snowball’. Choose a pot at least 30cm wide with drainage holes.

Container Growing Tips:

Use premium potting mix blended with NPK 4-18-38 with Cal-Mag for flower production
Place in a sunny position (6+ hours of light)
Water deeply but infrequently, letting surface dry out slightly between waterings
Feed every 2–3 weeks during spring–summer with diluted NPK fertiliser

Propagation from Seed:

Collect dry seed pods at the end of summer
Start seeds in seed trays filled with fine mix moistened with CompleteGrow 20-20-20
Keep warm (18–22°C) and moist; germination takes 3–6 weeks
Transplant to pots once seedlings have 2–3 true leaves

Propagation is also easy via division in autumn—split large clumps and replant immediately.

Fertilising Agapanthus: How to Boost Blooms and Support Healthy Foliage

While agapanthus are resilient, they bloom best when fed with a balanced, potassium-rich fertiliser. Avoid overloading with nitrogen, which encourages excessive leaf growth and fewer flowers.

Recommended Fertilisers:

NPK 20-20-20 – Great for initial planting and leaf growth in early spring
NPK 4-18-38 + Cal-Mag – Ideal for mid-season flowering boost and strong root health

Fertiliser Timing:

Spring: Begin with 20-20-20 every 2 weeks at 4 mL per litre
Mid-Spring to Summer: Switch to 4-18-38 fortnightly to promote flowering
Autumn: One final feeding before trimming back old stems

Trimming & General Maintenance:

Cut spent flower stalks down to base after flowering to conserve plant energy
Remove yellow or dead leaves to keep clumps tidy
Divide large clumps every 3–5 years to prevent overcrowding and reinvigorate blooms
Inspect regularly for snails and scale insects—treat early if noticed

With the right care and a consistent CompleteGrow fertilising schedule, your agapanthus will deliver year after year with lush foliage and vibrant flowers—even in poor soil or dry conditions.