Agapanthus 'Navy Blue' (Navy Blue agapanthus) care

Light

Most houseplants will scorch where agapanthus 'navy blue' thrives. Give it the windowsill you'd otherwise leave empty because everything else burned there. Full sun is essential for the rich flower colour and free flowering; give at least 6 hours of direct sun. In poor light stems stretch and blooms fade and thin out. A plant moved abruptly from low light to direct sun bleaches in 48 hours — always acclimatise over a week.

Watering

Aim for weekly during active growth and budding; taper off as leaves die back in autumn for agapanthus 'navy blue', but treat that as a starting point rather than a rule. A south-facing summer windowsill will dry the pot twice as fast as a north-facing winter room. Lift the pot; if it feels noticeably lighter than it did wet, water it. Water consistently while growing and flowering, especially container plants, which dry fast. Let the crown go dry over winter dormancy to avoid rot in this deciduous selection.

Soil and pot

Agapanthus 'Navy Blue' grows best in free-draining fertile loam. Likes a rich but sharply drained soil; add grit on clay. Excellent in pots in loam-based John Innes No. 3 with extra grit, where slight root restriction actually boosts flowering. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Agapanthus 'Navy Blue' sits happiest at around Ambient outdoor humidity humidity and 15-25°C (59-77°F). Not humidity-dependent; it is a border and patio plant. Open siting with free air movement helps keep foliage clean and discourages fungal leaf spotting. If you keep the room above 15 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed agapanthus 'navy blue' sparingly. From spring to flowering apply a high-potash liquid feed such as tomato food every 2-3 weeks to deepen colour and lift bloom count; cease after flowering and avoid nitrogen-heavy feeds that push leaf growth. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on agapanthus 'navy blue' in the Growli community. Each is annotated with the most common cause so you know where to start.

• Sparse flowering — Too much shade, excess nitrogen, or a freshly divided clump. Move to full sun, use high-potash feed, and let the roots become slightly congested before expecting heavy bloom.
• Container drying out — Pot-grown plants wilt quickly in heat; check moisture daily in summer and water before the compost fully dries to avoid bud abortion.
• Crown rot in winter — Cold, sodden compost rots dormant crowns. Keep pots dry and frost-protected over winter and ensure drainage holes stay clear.
• Agapanthus gall midge — Midge larvae deform and brown unopened buds. Pick off and bin affected buds to break the pest's cycle.

Propagation

Divide clumps in spring just as new growth starts, keeping several shoots per division; flowering may pause for a season. Named cultivars must be divided rather than seed-raised, as seedlings will not match the parent. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Agapanthus 'Navy Blue' is mildly toxic to pets. Agapanthus is not individually listed in the ASPCA Toxic/Non-Toxic Plants database and is not a true lily, so it does not cause lily-type renal failure. Its sap and rhizomes hold saponins that can cause drooling, oral irritation and vomiting if chewed. Treat with caution and verify with a vet on ingestion. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Agapanthus 'Navy Blue' deep-dive guides

Every aspect of agapanthus 'navy blue' care, each with its own calibrated guide:

• Agapanthus 'Navy Blue' watering schedule
• Agapanthus 'Navy Blue' light requirements
• Best soil mix for agapanthus 'navy blue'
• Agapanthus 'Navy Blue' fertilizing guide
• When to repot agapanthus 'navy blue'
• How to propagate agapanthus 'navy blue'
• Agapanthus 'Navy Blue' growth rate & size
• Agapanthus 'Navy Blue' cold hardiness
• Agapanthus 'Navy Blue' temperature & humidity
• Is agapanthus 'navy blue' toxic to cats & dogs?
• Is agapanthus 'navy blue' toxic to cats?
• Is agapanthus 'navy blue' toxic to dogs?
• Getting agapanthus 'navy blue' to bloom

Featured in these plant shortlists

Agapanthus 'Navy Blue' qualifies for 2 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
• Best houseplants for full sun — Houseplants that want direct sun — the species for a hot south or west-facing windowsill where shade-lovers scorch.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Agapanthus 'Navy Blue' is also commonly called Navy Blue agapanthus or dark blue lily-of-the-Nile.

• Peace lily care — light, water and common problems
• Bird of paradise care — light, water and common problems
• Hoya care — light, water and common problems
• All 5561 plant care guides in the Growli library