Pampas grass
Cortaderia selloana
also called cortaderia
Not a friendly plant, for all its presence — the leaf edges cut skin, and dead thatch left in the clump is a real fire risk.
- Type
- Grass · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green · Silver and gray
- Sunlight
- Full sun is not negotiable.
- Watering
- Drought-tolerant once established.
- Feeding
- No feeding needed.
- Frost tolerant
- Yes
- Flowering
- August
- Pruning
- Cut back to 30-45 cm in late March.
- Apr–Aug Spring Growth
- Aug–Oct Flowering
- Oct–Dec Growing
- Dec–Dec Leaf Fall
- Jan–Apr Leaf Fall
- Plant spacing
- 5 ft 11 in
- In-row spacing
- 5 ft 11 in
- Between rows
- 7 ft 5 in
- Square-foot density
- Not suited to SFG
- Root system
- A dense fibrous mat
- Working depth
- 8–24 in
- Can reach
- 5 ft down where the soil allows
- Spread
- 6–12 ft across, about 1–2× the width of the plant
- Shallowest pot
- 12 in of soil
Thousands of fine roots knit the top of the soil into a turf, which is what holds a bank together and what makes an established clump so hard to lift. Prairie grasses send a few roots far below the mat as well.
The crown becomes a dense woody mass that shrugs off a spade, so a pampas grass in the wrong place is a genuine job to remove. Site it once, and cut it back rather than moving it.
The habit is Pampas grass’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- Cats and dogs
- Confirmed safe
We say a plant is safe only where a named poison-control reference names that exact species and records it as non-toxic to both cats and dogs. Most plants are on nobody’s list, and their absence here is not a judgement about them. This is a record of what those references say, not veterinary advice, and it cannot account for your own animal, the quantity eaten, or a plant treated with anything.
- Razor-sharp leaf edges — gloves and long sleeves, every time.
- Dead material building up in the clump, which is a fire hazard.
- Can turn invasive in mild coastal areas.
Miscanthus, Verbena bonariensis, Crocosmia, Phormium
Grasses, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com