Northern sea oats
Chasmanthium latifolium
Also called Chasmanthium, River oats, Wild oats and Indian wood oats
Garden plant · GrassesIt seeds around hard in warm gardens and barely at all in cool ones, so watch the first two years before deciding where it goes. Cutting the oats for drying in late summer is also the simplest way to stop it.
Care at a glance
- Ease
- Easy
- Water
- Every 5 daysWater the ground — water at the base, in the morning, not over the leaves.
- Light
- Part shade — it is a woodland-edge grass
- Feed
- Not needed
- Humidity
- Average
- Hardiness
- Hardy — a cold winter RHS H5, to -15°C
- Size
- 0.9 m tall · 0.6 m across
- Lifecycle
- Perennial
- Origin
- Eastern and central North America
Is it safe for pets and people?
PetsNothing recorded against it
No animal-poison authority lists this plant either way.
PeopleNot checked yet
Nobody has checked this one against a source for us yet, so treat it as unknown rather than safe.
Checked against ASPCA and RHS on 2026-09-22. Where a source says nothing, we say nothing.
A guide, not veterinary or medical advice. If a pet or a person has eaten a plant and you are worried, call your vet or doctor now — don’t wait for signs to appear. Spotted a mistake? Tell us.
First signs of trouble
- Next spring there are broad-bladed seedlings in the gravel and between the paving six feet away, all of them with the same bamboo-ish leaf. Cut the oats in late summer if you want them for drying and the problem solves itself.Seedlings everywhere · disorder
- Rusty flecking on the broad leaves in a wet autumn, on the lower ones inside the clump first.Rust · disease