Sagittaria sagittifolia (Arrowhead) care

Light

Most houseplants will scorch where sagittaria sagittifolia thrives. Give it the windowsill you'd otherwise leave empty because everything else burned there. Full sun for strong growth and flowering; tolerates light shade with reduced vigour. Provide at least six hours of direct light. A plant moved abruptly from low light to direct sun bleaches in 48 hours — always acclimatise over a week.

Watering

Aim for keep in shallow standing water year-round for sagittaria sagittifolia, 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. Grow in up to 15-30 cm of water over the crown at a pond margin or in saturated marsh soil; tolerates slow-moving water but must stay wet.

Soil and pot

Sagittaria sagittifolia grows best in soft, fertile mud or aquatic loam. Prefers rich, mucky substrate at the water's edge; in baskets use heavy aquatic loam or clay-loam topdressed with gravel to keep water clear. 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

Sagittaria sagittifolia sits happiest at around Ambient outdoor humidity and -23 to 30°C (-9 to 86°F). An outdoor emergent aquatic unaffected by air humidity; warm shallow water and fertile mud govern its growth. If you keep the room above 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 sagittaria sagittifolia sparingly. Generally self-sufficient in fertile mud; for container plants add an aquatic fertiliser tablet in spring. Avoid loose granular feed that leaches into pond water. 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 sagittaria sagittifolia in the Growli community. Each is annotated with the most common cause so you know where to start.

• Spreading by tubers — Stolon-borne tubers let it colonise a pond margin quickly; grow in a basket and thin regularly to keep it contained.
• Submerged juvenile leaves — In deeper or moving water early growth produces ribbon-like submerged or floating leaves rather than arrow shapes; this is normal and resolves as emergent leaves form.
• Leaf grazing by waterfowl and insects — Ducks and aquatic insects graze foliage and dig tubers, thinning stands; protect young plants until well rooted.
• Decline if water dries — It weakens if the rootzone dries out; maintain shallow standing water or saturated mud through the season.

Propagation

Lift and separate the overwintering tubers (turions) or divide rhizome clumps in spring, planting into wet mud; also grows from fresh seed sown on saturated soil. 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

Sagittaria sagittifolia is mildly toxic to pets. Sagittaria sagittifolia is not individually listed by the ASPCA as toxic or non-toxic to pets. Cultivated tubers are eaten in Asia after cooking, but the raw plant is acrid and not established as pet-safe; treat with caution around cats and dogs and verify with a vet before assuming it is safe. 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.

Sagittaria sagittifolia deep-dive guides

Every aspect of sagittaria sagittifolia care, each with its own calibrated guide:

• Sagittaria sagittifolia watering schedule
• Sagittaria sagittifolia light requirements
• Best soil mix for sagittaria sagittifolia
• Sagittaria sagittifolia fertilizing guide
• When to repot sagittaria sagittifolia
• How to propagate sagittaria sagittifolia
• Sagittaria sagittifolia growth rate & size
• Sagittaria sagittifolia cold hardiness
• Sagittaria sagittifolia temperature & humidity
• Is sagittaria sagittifolia toxic to cats & dogs?
• Is sagittaria sagittifolia toxic to cats?
• Is sagittaria sagittifolia toxic to dogs?
• Getting sagittaria sagittifolia to bloom

Featured in these plant shortlists

Sagittaria sagittifolia qualifies for 3 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.
• Best houseplants for a cool room — Houseplants that tolerate cool conditions down to about 10°C — for an unheated spare room, hallway, porch or a home kept cool.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Sagittaria sagittifolia is also commonly called Arrowhead or Old World Arrowhead.

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