Nasturtium

Why nasturtium is the safest cottage flower.

Yes — nasturtiums are safe for cats. The ASPCA lists Tropaeolum majus (garden nasturtium, also called Nose-Twister or Nose-Tweaker for the peppery smell) as non-toxic to dogs, non-toxic to cats, and non-toxic to horses. The clinical-signs field is the one to notice: No records of toxic ingestion from this plant. That is among the strongest safety verdicts ASPCA ever gives.

The ASPCA verdict, verbatim: Toxicity: Non-Toxic to Dogs, Non-Toxic to Cats, Non-Toxic to Horses · Family: Tropaeolaceae · Additional Common Names: Nose-Twister, Nose-Tweaker · Scientific Name: Tropaeolum majus · Toxic Principles: Non-toxic · Clinical Signs: No records of toxic ingestion from this plant.

The nasturtium / watercress naming tangle

The single most common source of confusion on this page is the name itself. Two completely unrelated plants share the common name "nasturtium":

• Garden nasturtium (this page) — Tropaeolum majus, family Tropaeolaceae, native to the Andes. The peppery edible cottage flower with round leaves and spurred trumpet blooms. ASPCA non-toxic.
• Watercress — Nasturtium officinale, family Brassicaceae, a European aquatic herb in the mustard family. Also ASPCA-style non-toxic but a different plant entirely.

Both are peppery, both are edible, both got the "nasturtium" common name in different historical traditions. Both happen to be safe for cats, so the practical answer is the same in either case — but if you are reading care guides or seed packets the distinction matters. Tropaeolum if it looks like a cottage flower; Nasturtium if it looks like a watercress salad green.

Why the peppery flavour matters

The flavour that makes nasturtium a salad green is the same flavour that makes it cat-self-deterrent. Tropaeolum produces glucosinolates (the mustard-oil compound family) that give the leaves and flowers their sharp peppery bite. Humans enjoy this; most cats taste it once, dislike it, and walk away. From a cat-household perspective this is a perfect combination: ASPCA non-toxic safety profile plus sensory self-limiting — the cat is unlikely to keep eating it even when chemically safe.

This is the same principle that makes basil, rosemary, and the rest of the safe culinary-herb cluster low-actual-incident: ASPCA-safe plus aromatic-deterrent. Nasturtium is the equivalent in the flowering-ornamental category.

Edible — for humans and incidentally for cats

Nasturtium is a popular edible flower. Petals go on salads; leaves go on sandwiches; immature seed pods are pickled as a caper substitute. None of this introduces a cat risk. If your cat steals a nasturtium-garnished plate, no concern. If you grow nasturtiums on the kitchen windowsill, no concern. If the cat noses through the bed and chews a flower while you garden, no concern.

Pairing nasturtium in a cat-safe garden

Nasturtium fits cleanly into a cat-safe ornamental and edible mix:

• Marigold — another bright safe cottage flower, ASPCA non-toxic.
• Calendula — the "pot marigold," similar safe edible-flower profile.
• Basil — safe culinary herb; nasturtium and basil are classic companion plants.
• Rose — non-toxic flowering shrub for the same border.
• Sunflower — taller safe annual for height behind low nasturtium.

Avoid mixing with foxglove, larkspur, oleander, or lily-of-the-valley without barriers — those are the highly-toxic cottage-garden flowers most likely to be confused at a casual glance by a child or a guest filling a vase. For the full toxic landscape see toxic plants for cats and for more cottage-flower options cat-safe plants.