Pampas grass: planting, winter protection, cutting back and growing from seed

In short: Pampas grass (Cortaderia selloana) is a South American grass with plumes up to 3 m tall. It wants full sun, deep well-drained soil and above all dryness in winter. It is planted in spring, the leaves are tied up for winter and it is cut back only in March. Growing it from seed is slow and uncertain; it is more reliable to buy a named female variety.

Pampas grass is the largest ornamental grass that you can grow in a garden here. From a dense clump of narrow grey-green leaves, stems with fluffy silvery white or pinkish plumes rise at the end of summer. They last on the plant right through the winter, and dried they are now widely used in interior arrangements too.

For a general overview of grasses for the garden see the article ornamental grasses – a decoration for the modern garden. Here we go into detail on pampas grass only: how to choose it, plant it, get it through winter and why it does not pay to grow it from seed.

Male or female plant: why it matters

Pampas grass is dioecious. One plant bears either only male or only female flowers. According to botany.cz the female plant has plumes with horizontally spreading branches, which look full and fluffy. Male plumes are narrower, the branches point more upwards and overall they look sparser.

Ornamental varieties at garden centres are therefore almost always female plants propagated by division. Their appearance is guaranteed and, without a male plant nearby, they do not form viable seeds, so they do not spread in the garden.

Well-known varieties

Heights are approximate. According to botany.cz variegated varieties are usually smaller than the botanical species.

Pampas grass from seed: it can be done, but expect a lottery

Pampas grass seeds are sold and germinate fairly readily. The seedlings are genetically diverse, though: roughly half grow into male plants with sparse plumes, the colour and height vary, and the first plumes appear only after two to three years. Anyone who wants a particular look will save time by buying a named variety in a pot.

If you want to try it from seed, proceed as follows:

1. Timing. Sow in March to April in a tray of fine seed compost.
2. Sowing. The seeds are tiny and germinate in light, so just spread them over the surface and press them in. Do not cover them.
3. Moisture and warmth. Cover the tray with film or a clear lid and keep it at 18–22 °C in light, but not in direct sun. They germinate in 2–4 weeks.
4. Pricking out. When the seedlings are 5–8 cm tall, transplant them one at a time into pots 8–10 cm in diameter.
5. First year in a container. Grow the young plants in a pot for the first season and for winter put them in a bright, unheated room. Plant them in the bed only the following spring, when they are strong enough.

Judge the result only in the third year, by the plumes. Male plants that you do not like can be dug up while the clumps are still small.

Planting: choose the place the first time

A mature clump measures 1.5–2 m across, and an old one can be dug up only with great effort. The leaves have tiny sharp teeth along the edges that cut like paper. So do not plant pampas grass by a pavement, a sandpit or places where children walk.

• When. In spring, from April to May, so that it roots before winter. Autumn planting is risky.
• Position. Full sun and a spot sheltered from the cold east wind, ideally facing south.
• Soil. Deep, nutritious, but well-drained. Work coarse sand or gravel into heavy clay soil, or plant on a gentle mound.
• How. Dig the hole twice as wide as the root ball. Plant at the same depth as it was in the pot and water regularly in the first summer.

An established plant then needs watering only in a long dry spell. Feeding once in spring with a weak dose of general-purpose fertiliser is enough.

Winter protection for pampas grass

The British RHS places pampas grass in hardiness category H6, that is, roughly down to −20 °C. Botany.cz, however, points out that in our conditions it does not always tolerate stronger frosts well and does better in a mild oceanic climate. In practice a clump is more often killed by water that runs into the centre in winter and freezes than by frost.

1. In autumn do not cut the leaves or plumes; they protect the heart of the clump.
2. At the end of October or in November gather the leaves together in gloves and tie them with string into a "plait". Water then runs down the leaves and out, and does not run into the centre.
3. Cover young plants at the base in their first winter with a layer of dry leaves or evergreen branches. The RHS recommends a thick dry layer of mulch in the first winter.
4. Move plants in containers against the wall of the house under a roof and wrap the container in hessian or bubble wrap.

You will find more advice on autumn preparation of beds in the article important tips for preparing the garden for winter.

Spring cutting back and dividing the clump

Cut it from March to April, before the new leaves grow. Take thick leather gloves, long sleeves and eye protection.

• Untie the plait and cut off the old plumes at ground level.
• Comb out the dry leaves by hand in a glove or with a rake. If the clump is full of dead leaves, you can cut the whole thing to 20–30 cm above the ground.
• Do not burn it. Fire in the clump is dangerous and can also damage young shoots.

When the clump thins out in the middle, divide it in spring with a sharp spade or an axe into parts with enough roots. With large specimens it is a job for two. The general procedure for cutting back ornamental grasses is also described by the RHS in its guide to spring cutting back.

Is pampas grass invasive?

In warmer parts of Europe, yes. In Spain the whole genus Cortaderia is entered in the national catalogue of invasive species, so it may not be sold or planted there. Portugal, Italy and France also list it as invasive, where it overgrows coasts, embankments and abandoned land.

In the Czech Republic it does not spread yet. It is limited by cold winters and, above all, by the fact that female clones are grown, without pollination. The risk rises when male and female plants grow in one garden or in the neighbourhood, typically from seed. If you have both, cut off the plumes before the seeds ripen, that is in September to October, and use them in arrangements.

Plumes for a vase and drying

For drying, cut the plumes soon after they emerge, while they are still more closed. Tie them and hang them head down in a dry, airy place for two to three weeks. To stop them falling apart you can spray them with hairspray. You will find other plants suitable for dried arrangements in the article plants for drying and making dried arrangements.

Frequently asked questions

When should I cut pampas grass?

In spring, from March to April, before new leaves shoot. Do not cut it in autumn; the leaves protect the centre of the clump from winter wet.

How do I overwinter pampas grass?

In autumn tie the leaves into a plait so water does not run into the centre. Cover young plants at the base in their first winter with dry leaves or evergreen branches.

Why is my pampas grass not flowering?

Most often the plant is young, especially from seed, or it stands in shade. Recently divided clumps are also slow to flower. The plumes usually appear in the second to third year in full sun.

Is pampas grass poisonous to dogs and cats?

According to the ASPCA, pampas grass is not poisonous. The sharp leaf edges are dangerous, though, as both people and animals can cut themselves on them.

How fast does pampas grass grow?

A young plant from a pot forms a large flowering clump in two to three years. From seed it takes longer and the first plumes come in the third year at the earliest.

Recommended products

We do not currently have pampas grass seeds or plants on offer. The following are suitable for spring cutting and care:

• SingleStep hedge shears FISKARS – long handles for cutting the whole clump without bringing your hands close to the sharp leaves.
• Grass and hedge shears FISKARS – for tidying the edges and smaller clumps.
• Canary grass, ornamental grass – 120 seeds – a smaller ornamental grass that you can grow from seed in one season, also for dried arrangements.

Sources

• Cortaderia selloana: hardiness H6, position, winter mulch (Royal Horticultural Society)
• Ornamental grasses: cutting back (Royal Horticultural Society)
• Pampas grass, Cortaderia selloana: dioecy, hardiness here (botany.cz)
• Catálogo Español de Especies Exóticas Invasoras (Spanish Ministry for the Ecological Transition)
• Pampas Grass: non-toxic to dogs, cats and horses (ASPCA)

Updated: 27 September 2026