Photo: Jasper33 / Public domain

Marsh Marigold Care

Caltha palustris · Ranunculaceae

⚠️ Toxic to pets 🎯 Easy ☀️ Bright with some direct sun 💧 Every 7 days

🕮 6 min read 🕓 Last reviewed: 2026-08-23

Care at a glance

Light

Bright with some direct sun

Temperature

2–24 °C (36–75 °F)

Soil

a nutrient-rich aquarium substrate (or attached to wood/rock)

Difficulty

Easy

Mature size

20–45 cm (8–18 in)

Pet safety

Toxic to pets

Care effort Medium

The short version

Beginner-friendly and forgiving.
Give it Bright with some direct sun.
Water every 7–7 days.
Keep away from cats and dogs.

The Marsh Marigold (Caltha palustris) is an aquatic plant grown submerged in freshwater aquariums. It comes from Northern Hemisphere and is rated Easy to keep, reaching 20–45 cm. Here is how to grow it underwater — lighting, substrate, CO₂, placement and propagation.

Also known asCaltha palustrisリュウキンカ驴蹄草Calta palustrePopulage des marais

📋Quick facts

Growth rate	Moderate
Mature size	20–45 cm (8–18 in)
Native region	Northern Hemisphere
Plant family	Ranunculaceae
Toxicity	Toxic
Air-purifying	No
Ideal for	beginners, a pop of colour

⚖️Pros & cons

Pros

Hard to kill; great for beginners
Flowers indoors
Compact — fits a desk or shelf

Cons

Toxic to cats and dogs
Needs high humidity to look its best
Needs a bright, sunny spot

🐟Growing it in an aquarium

Keep the water at 2–24 °C. Stable, gently moving water and regular partial water changes keep it healthy; sudden swings in temperature or chemistry cause melting.

Light

Give it Bright with some direct sun-equivalent aquarium lighting. Low-tech tanks suit undemanding species; brighter light (and often CO₂) brings out the best colour and compact growth but also feeds algae, so balance it carefully.

Soil

Plant it in a nutrient-rich aquarium substrate (or attached to wood/rock). Rooted species are hungry feeders — use root tabs or a liquid aquarium fertiliser (and CO₂ for demanding types). Epiphytes like Anubias, Java fern and Bucephalandra must NOT be buried: tie or glue their rhizome to wood or rock, or they rot.

Its size and habit suit a spot in the foreground, midground or background depending on how tall it grows; trim and replant tops to keep it dense.

✂️How to propagate, step by step

Spring and early summer, during active growth, give the best success. Here is how to do it, step by step:

division at repotting

Water the plant the day before to reduce stress on the roots.
Slide it out of its pot and gently shake off the loose soil.
Tease the root ball into sections, each with healthy roots and a few shoots.
Pot each section into fresh mix at its original depth.
Water them in and keep out of direct sun for a week while they recover.

seed

Sow fresh seed onto the surface of moist, fine seed-starting mix.
Cover lightly only if the seed needs darkness; most need warmth of 20–25 °C.
Keep humid under a clear cover in bright, indirect light.
Germination ranges from days to months depending on the species — be patient.
Prick seedlings out into their own small pots once they have a few true leaves.

🔬Classification

Plant type	Aquatic plant
Genus	Caltha
Family	Ranunculaceae · Ranunculaceae
Native to	Northern Hemisphere

🩺Common problems

Symptom	Likely cause	What to do
Yellowing leaves	Usually overwatering or poor drainage	Let the soil dry more between waterings and make sure the pot drains.
Dropping leaves	A sudden change in light, temperature, or watering	Keep conditions stable and avoid moving it often.
Brown spots on leaves	Inconsistent watering, cold draughts, or fungal issues	Water evenly, keep it warm, and remove badly affected leaves.

🩺 Plant Doctor →

🐛Pests & prevention

The usual indoor pests are spider mites (fine webbing, speckled leaves), mealybugs (white cotton-wool tufts), scale (small brown bumps), and fungus gnats (tiny flies from soggy soil). Inspect any new plant before it joins the others, wipe the leaves now and then, and let the topsoil dry to keep gnats away. At the first sign, isolate the plant, wipe or rinse off what you can, and treat with insecticidal soap or neem oil every week until it is clear.

🐾Is it safe for pets?

The Marsh Marigold is toxic to cats and dogs (protoanemonin). Keep it out of reach of pets and children. If you think an animal has chewed it, contact your vet or a pet poison line. If a curious cat or dog chews it, eating it can cause drooling, vomiting, and general stomach upset. It is rarely life-threatening in small amounts, but rinse the animal’s mouth, take away any plant pieces, and call your vet if symptoms are severe or last more than a short while.

Toxicity information is a general guide based on ASPCA data. If your pet or child may have eaten any part of a plant, contact a vet or poison control right away.