Pampas grass: all about planting, care & pruning

Lukas
Lukas
Lukas
Lukas

I studied agricultural sciences with full conviction - an obvious choice for me, as I grew up on my parents’ farm and learned early on to find joy in taking care of plants and animals.

Favourite fruit: grapes, mangos and bananas.
Favourite vegetables: brussels sprouts, spinach and potatoes

With its fluffy flowers, pampas grass is a real eye-catcher in the garden in summer. You can find everything you need to know about pampas grass here.

Pampas grass garden
Pampas grass is very popular as an ornamental in the garden [Photo: Kathryn Roach/ Shutterstock.com]

Pampas grass (Cortaderia) is one of the most popular ornamental grasses in our gardens. It can be found in solitary positions, as an attractive individual plant, or in clusters, as a decorative screen. Pampas grass grows in clumps, so it always resprouts from the parent plant, and belongs to the sweet grass family (Poaceae).

Pampas grass: properties and appearance

American pampas grass (Cortaderia selloana) in particular is very common in our area. Originally it comes from a subtropical area, the “Pampas” grass steppe on the southeast coast of South America. In summer, the non-toxic plant forms large, mostly silvery-white flower panicles, which present an impressive spectacle due to their stem length of up to 2.50 m and more. However, depending on the variety, the ornamental grass also displays flower fronds in other pastel shades.
However, the wintergreen leaves grow to a maximum height of 1 m. Here, too, you can find a wide variety of leaf patterns. With its graceful growth and the particular height of its inflorescence, pampas grass is an impressive exotic addition to ornamental gardens.

Different forms and varieties

Worldwide we find a huge, previously undocumented diversity of different forms and varieties of pampas grass. This beautiful ‘sweet’ grass is distinguished mainly by the height of growth and the colour of its flower panicles.

Pampas grass in the sun
Pampas grass loves the sun due to its South American origin [Photo: tamu1500/ Shutterstock.com]

Pampas grass varieties: the 5 most popular varieties

‘Compacta’ is a small, robust ornamental grass. Its flower stems reach a height of up to 120 cm. The eyrie also has a diameter of half a metre. The panicle, which blooms in September-October, has a creamy white colour.
The leaves of ‘Compacta’ pampas grass are green and deciduous. As long as the ornamental perennial is not exposed to waterlogging, it can be well established in stone beds or rockeries. It is relatively compact growth makes it a good eye-catcher without blocking your entire view at the same time.

‘Evita’ is also a smaller, but quite elegant grass. A large number of light yellow to yellow-gold flower fronds form from August to October. The leaves are grey-green and hardy. The whole plant grows very sprawlingly. Due to the compact growth and long-lasting flowering ‘Evita’ is also well suited for garden containers. It is important here that the plant has enough space to develop, so do not choose a tub that is too small and use potting soil that is well permeable to water. Pampas grass grows about 1.20 m high and prefers a semi-shaded place. If planted in containers, a change of location to a frost-protected room would be favourable for overwintering without damage. Often, this type of ornamental grass blooms in the first year of planting.

‘Rosea’ is distinguished by its rare pink panicles. It is a very special beauty for the garden and grows up to 2 m high. The flowers of ‘Rosea’ appear in September and October and are pink to grey in colour.
The foliage consists of narrow, green-grey leaves that grow to about 1 m long.

‘Rendatleri’ is an ornamental grass plant that also has pink flowers and can reach a height of up to 250 cm. Its leaves are deciduous and grow to almost 150 cm long. The beautiful flowers can be seen from September to November. They are a real eye-catcher in any garden.

‘Sunningdale Silver’ reaches an imposing size of 250 cm. ‘Sunningdale Silver’ is a slender grass beauty with long silvery white fronds and can be described as a hardy classic pampas grass. It is most impressive as a solitary plant. The leaves are very narrow grey-green and, like all pampas leaves, sharp-edged. They can reach a length of 120 cm. The eyrie of the plant can spread up to a diameter of 130 cm.

Pampas grass as a screen in the garden

If you want to plant pampas grass as a screen, you should choose grasses with tall growth. ‘Sunningdale Silver’, ‘Rendatleri’ and ‘White Feather’ all reach a height of up to 250 cm. Pampas grass is very decorative and fast-growing. It is especially ideal for the plants if the grassy privacy screen is for protection against the sun in summer – they particularly like sunny places.

Pampas grass screen
Pampas grass can serve as a screen in summer and autumn [Photo: Filippo Carlot/ Shutterstock.com]

Before the onset of winter, the fronds should be tied together, so that the grass is better protected from winter moisture. However, this limits the visual protection. The plants should be cut back once a year, in the spring months. For a short time, this eyecatcher is almost completely lost. But after a few weeks, new shoots grow and you can look forward to the budding of flowers.

Planting pampas grass: location and procedure

The location for the pampas grass should be carefully selected – not because it is so demanding, but rather because of its enormous growth potential.

  • Pampas grass requires sufficient space
    If you would like to bring pampas grass into your garden as an ornamental plant, please note from the outset that even small varieties can grow to a good 120 cm and a diameter of one metre or more. So you need enough space.
  • Pampas grass loves sunny and warm places
    Even if you have chosen a sunny, warm location, the roots of pampas grass still need loose, permeable soil. Soils too rich in clay would retain too much moisture in winter and the roots would become rotten. The ornamental grass likes if you mix sand or small gravel in. A good dose of humus or a primarily organic slow-release fertiliser such as our Plantura All Purpose Plant Food should also be added.
Pampas grass in a park
Cortaderia selloana is becoming a leading element in the garden [Photo: Debu55y/ Shutterstock.com]

When to plant

Pampas grass should be planted in spring or early summer. This will allow the new addition to develop well over the course of the year, and by the time the next winter comes around, it will be well rooted to the site and ready for cold temperatures.

How to plant pampas grass

The planting hole should be dug to a depth of about 40-45 cm. It is advisable to water the plant’s eyrie well before planting. The best way to do this is to submerge it in a large bucket or tub of water until it is completely soaked. Then put in the planting hole, fill with soil and press firmly. Pay attention to the distance between each plant (100-130 cm). No runners form with pampas grass, so a rhizome barrier is not necessary.

Planting pampas grass: step by step instructions

  • After the ground is frost-free (after the last frost), pampas grass can be planted in open ground.
  • Dig a planting hole of about 40 – 45 cm – also make sure that the width is sufficient.
  • If the soil is not permeable enough, mix in a little sand or fine gravel.
  • Add a little humus-rich planting substrate and insert the watered plant.
  • Depending on the height of growth of the grass, a distance of 1 – 1.3 m should be maintained between plants.
  • Water especially well for the next 14 days, but avoid waterlogging.
Using a spade to dig a planting hole
The planting hole is dug at the depth of the root ball [Photo: Poprotskiy Alexey/ Shutterstock.com]

Caution: Be sure to wear gloves when planting pampas grass. The foliage is extremely sharp and can inflict nasty cuts.

Detailed expert instructions on planting pampas grass can be found here.

Pampas grass in pots and on the balcony

Pampas grass is not only an attractive addition to the garden when planted in beds. It also looks very decorative in tubs and pots, on terraces and balconies. In a pot or tub, pampas grass usually does not reach the same height of growth as in flowerbeds – it remains somewhat smaller than in open ground. Nevertheless, the planter must be generous in depth and width, it should have a capacity of at least 40-45 litres. Use suitable soil for planting, such as our peat-free Plantura Organic All Purpose Compost, which contains all the necessary nutrients for healthy growth.

Organic All Purpose Compost, 40L
Organic All Purpose Compost, 40L
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When planting pampas grass in a pot, it is advantageous if the bottom has drainage holes to prevent waterlogging. You can also put shards of pottery or larger pebbles as the bottom infill, this will give you a simple drainage layer that will have the same effect. If there are drainage holes, the pot should be placed on a trivet. In order to be able to move heavy pots in winter without much effort, and thus protect them from severe cold, it is advisable to place them on small rolling boards at the time of planting.

More useful tips for planting pampas grass in a pot can be found here.

Propagating and dividing

There are two ways to propagate pampas grass: First, you can sow the grass yourself. Secondly, you can quickly and easily turn one plant into several plants by dividing the pampas grass. Regardless of which propagation method is chosen, we’ll take a closer look at both methods.

Sowing pampas grass and growing in a pot

If you want to sow pampas grass, you can either use seeds you have collected yourself from existing plants in your garden, or you can buy seeds from a specialist supplier. The latter is the better option, because the pampas grass is dioecious (so there are male and female plants). Since you cannot tell what kind of plant it is from the seeds, you should buy from a supplier where you’ll only find female seeds, because female grasses grow much more luxuriantly and also form larger fronds than the male plants.

You can sow the seeds in the pot as early as March and leave them there until the last frost in May. To do this, place the seeds (at some distance) in pots filled with good potting soil. Then gently press down the seeds and water them. As you proceed, make sure that the swelling and germinating seeds never dry out. Dryness in the germination process could cause failure. Either cover the pots with seeds with a sheet of glass or periodically spray the surface with a fine spray bottle.

Soil in planting pots
Pampas grass can be grown in advance in pots [Photo: Artur Szczybylo/ Shutterstock.com]

Note: Do not add additional soil over the seeds after pressing. Pampas grass is a light germinator, so it needs light exposure to germinate.

You can then plant the germinated plantlets outdoors in May, when frost is no longer expected. If you want to play it safe, repot the plantlets once again and house them in the container until the following year. Then they are guaranteed to be tough enough to stand up to the outdoors.

Dividing pampas grass

Vegetative breeding by dividing a mother plant is easier and more effective. To do this, uncover all or part of the eyrie of the desired grass from your garden and cut a piece of it with a spade. Then the divided plant part should placed in a sufficiently large, prepared hole, into which you should ideally put some humus-rich compost for initial fertilisation. Preferably, pampas grass should be divided in the spring, after it has been cut back. Then it will have enough time to root again before winter.

Caring for pampas grass

Pampas grass is a fast-growing ornamental plant. During the growth phase, it needs plenty of nutrients, so regular fertilisation makes perfect sense.

Fertilising: organic or mineral fertiliser

Regular application of fertiliser is very important during the biggest growth phase (spring to late summer).

Pampas grass plant
Spring to late summer fertiliser should be applied to pampas grass [Photo: zzz555zzz/ Shutterstock.com]

Therefore, when planting or transplanting, it is advantageous to add a starter fertiliser to the planting hole right away. For the extra portion of nutrients in particularly vigorous years and the supply of all trace elements, it is advisable to apply a complete fertiliser. Primarily organic fertilisers are the most sustainable choice and also bring many benefits. On the one hand, they promote soil life and enrich the soil with new organic matter. On the other hand, the structural condition of the soil is also positively influenced. Last but not least, primarily organic fertilisers are resource-saving because they are largely made from organic waste and other recycled biological material. Our Plantura All Purpose Plant Food is also a sustainable and plant-based fertiliser.

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Watering pampas grass

As a rule, the root system of pampas grass is sufficiently developed to absorb enough water from the soil. Additional watering is useful only in particularly dry periods during the main growth. However, if the pampas grass is in a pot, then, of course, it needs much more regular watering. But waterlogging should be avoided at all costs. If a pampas grass has been transplanted or divided and then replanted, be sure to water it regularly until it has acclimatised sufficiently to its new location. But again: waterlogging should be avoided at all costs.

Pampas grass by a pond
Pampas grass naturally likes to grow close to water and should not dry out completely [Photo: PhotoMagicWorld/ Shutterstock.com]

Cutting back pampas grass: expert tips

Pampas grass is one of the most beautiful ornamental grasses. It should be cut back once a year so that the special lushness of its flower heads is promoted or maintained.

Do you have to prune pampas grass?

Pruning is very important because this ornamental grass is an eyrie-forming plant. It always sprouts from the mother plant. Since the stems and leaves dry out in late autumn, it is necessary to provide enough space and light for the new shoots in the spring. This is the only way to guarantee dense and beautiful new growth.

How and when to cut back pampas grass

It is important to make sure that pruning is done in the spring, from March to May, depending on the weather. It is not good to do this maintenance work in autumn, because the stems of pampas grass are hollow. If pruned in autumn, too much water would accumulate inside and the perennial would most likely rot partially or even completely due to the moisture.

Pruned pampas grass
Shortly after pruning, the pampas grass begins to sprout again [Photo: simona pavan/ Shutterstock.com]

If your ornamental grass is in a container and moved to a frost-free area over the winter, do not prune it until spring. The ideal time is when the first new shoots are visible. Then cut your pampas grass down to about 15 to 20 inches with a sharp pair of garden shears.

Caution: Remember to always wear gloves when working with pampas grass so you do not cut yourself on the leaves.

For detailed instructions and more tips on pampas grass pruning see our special article on this.

Successfully overwinter pampas grass

Pampas grass is not completely hardy in our latitudes and requires winter protection. In late fall, when the stems have dried up, tie the upper part together. You should spread a layer of straw or dry leaves on the lower part of the plant and then layer brushwood on top. If possible, wrap the plant in a fleece or coconut bark at full height. Protected in this way, the pampas grass can withstand colder temperatures of up to – 10 to -15 °C.

Pampas grass in the snow
Cortaderia selloana is hardy in the bed but needs its foliage for protection [Photo: Ian Grainger/ Shutterstock.com]

If your pampas grass is in a planter, then you should find a winter home for the ornamental grass and water it moderately. If it is not possible to bring the plant into a protected room, then wrap the pot with bubble wrap and place it on a piece of Styrofoam or on some wooden slats. Again, it is best to wrap the grass in a fleece for its entire height. So that winter can come.