Avicennia germinans
Avicennia germinans · Acanthaceae
The gardener's calendar
In autumn, ease off feeding and take the chance to clean up around avicennia germinans and prepare for winter.
ID card
- Common name
- Grey mangrove or Black mangrove
- Family
- Acanthaceae
- Foliage
- Evergreen
- Flowering
- Spring to summer, discreet yellow flowers
- Adult size
- 2 to 12 m depending on conditions
- Hardiness
- Tropical to subtropical, sensitive to cold
- Origin
- Coastal tropical and subtropical regions of the Americas
- Natural habitat
- Mangrove zones, estuaries, halophilic environments
Care
Light exposure
Avicennia germinans thrives in full sun, ideally 6 to 8 hours daily. In less sunny regions, it tolerates bright filtered light. Direct sun exposure is preferable to encourage compact growth and abundant flowering.
Watering
This species tolerates brackish and salt water extremely well, which is its major asset. In cultivation, keep the substrate moist during active growth, then reduce slightly in winter. Avoid complete drying out, but drain well to prevent chronic waterlogging.
Soil and substrate
Prefer a draining mixture enriched with organic matter: horticultural soil mixed with sand or perlite. Avicennia adapts to poor soils and tolerates salinity, unlike most ornamental plants. Install a good drainage system in the pot.
Fertilizing
Fertilize moderately during the growing season (spring-summer) with diluted balanced fertilizer every 3 to 4 weeks. Reduce or stop feeding in winter. Excess nitrogen can reduce winter hardiness; favor a lightly dosed formula.
Pruning and maintenance
Prune lightly after flowering to maintain a compact shape and remove dead or crossing branches. In tropical climates, Avicennia grows vigorously and may need annual pruning. Remove weak stems to open up the canopy.
Diseases and pests
Indoors or in humid temperate climates, watch for mealybugs and spider mites, especially if the air is dry. Root rot can occur with persistent waterlogging. Promote regular ventilation and measured watering to prevent these issues.
Did you know?
Avicennia germinans is a pioneer species of mangroves: its seeds germinate *in situ* on the tree (vivipary), producing fleshy rootlets that fall and root immediately in the mud. This spectacular adaptation allows it to rapidly colonize unstable coastal zones. In Florida and the Caribbean, this mangrove plays a crucial ecological role in stabilizing banks and providing refuge for aquatic wildlife.
Where to buy it
Best planted in autumn so the roots settle in before summer, or in early spring once the frost has passed. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, October, November.
Add this plant to my garden →Plants from the same family
- Uruguayan Firecracker PlantDicliptera squarrosa
- Hungarian Bear’s-BreechesAcanthus hungaricus
- Bear's breechesAcanthus mollis
- Ethiopian acanthusAcanthus sennii
- GoldfussiaStrobilanthes anisophylla
- Avicennia marinaAvicennia marina
Tips generated and checked by Viridia — adapt them to your local climate.