Pampas grass can be used in a border, or as a specimen, and forms vary from upright feathery plume to almost flowing ostrich feather. The flowering stems can be either mink-brown, soft silver-pink or cream, but all tend to weather to light-beige as winter progresses.
Where to plant
These grasses demand a warm position that gets either full sun or partial sun. Given this they will flower well and named forms are hardy enough to survive tough British winters if they are planted before midsummer’s day. This gives them enough time to establish some roots, before winter bites.
Fabulous evergreen foliage
The foliage endures through winter and there are variegated and golden foliage forms that shimmer lightly. Heights can differ from waist-high to over six feet (or 2m) so there’s a Pampas grass for every situation. Their great value is their architectural presence and many perform in October when most of the garden is in retreat. However they do need space to shine.
This grass gets its name cortaderia from the Spanish word for cut – cortadera, and the leaf edges of all cortaderias are savage. Great care must be taken to avoid getting the leaves near the eyes. Wear thick gloves whenever you tackle the foliage and, if you have young children, I recommend not planting one.
The foliage is also tough and some gardeners try to burn back the foliage. This is not necessary. Take a stout pair of sharp hand shears if you want to cut back, or tidy your plants by removing individual leaves in March and April as the foliage can get very weatherbeaten in cold winters. This tidying must be done: untended plants soon look scruffy.
Smaller Pampas grasses can be accommodated on the outer edges or a corner of a border containing other grasses and late-season perennials. Purples set off the silver awns and Monarda ’Vintage Wine’ and Vernonia crinita ‘Mammuth’ are both tall enough to create a contrast. Warm-orange dahlias (like ‘David Howard’) or deep-reds (Like ‘Chat Noir’) also add grandeur. Avoid pale flowers: go for a vivid contrast against the whie to silvery awns.
Large, impressive pampas grasses can be used as specimens given their own space.
Choosing a variety
Some tend to be dioecious. That means that plants either produce female of male flowers on separate plants. The female flowers are the most impressive. Always buy named pampas grasses from a grass specialist or excellent nursery: they will hopefully be dividing clumps and not raising inferior seedlings that could cause disappointment.
There was a recent RHS trial, 2007 -2009, which I helped judge - see varieties for AGM winners.
Named Pampas grasses
This is the most commonly grown species in Britain and it was a great Victorian favourite in gardens, although they knew it then as Gynerium argenteum. William Robinson (1838 - 1935 ), the great Victorian gardener and writer, grew it as a very young man at Glasnevin Botanic Gardens and he helped popularise it. E.A. Bowles (1865 -1954 ) also used it close to water at his Myddleton House Garden near Enfield in Middlesex.
C. selloana is found growing in the wild in Brazil, Chile and Argentina on flat, windy ground between the Andes Mountains and the sea. These areas are known as The Pampas. Summer temperatures can be very hot, but this plant also endures great humidity in the wild. It has never set seed for me as most forms only flower from October onwards. However seedlings are a huge problem in parts of north-west America, where humid summer weather forces the plants into flower early. Climate change may cause similar problems here in the future. On the subject of climate change forms of C. selloana are very drought tolerant. Other species are found in New Zealand, but they still have dangerous leaves.
Varieties of Cortaderia selloana
This is the compact white-feathered pampas grass with narrow plumes that tends to flower in late-summer or early autumn. The further south you are the earlier is. Grey-green leaves, hardy and it reaches between 5 and 7 ft (up to 2m)
A cold-tolerant form from America bred by Kurt Bluemel, with grey-to beige tinted plumes that rise above arching foliage. Glorious in autumn and highly admired on the trial. (2.4m x 1.5m)
A very upright new pampas from Luc Klinkhamer with lots of cream-yellow to white flowering heads. Earlier to flower than many. (1.7m x 2.7m)
‘Highfield Pink’ AGM
Plumes open pale-pink and then bleach to white. Universally admired on the trial for its graceful more-open flowers and loosely arranged stems. Tall but airy. (3.6m x 3.2m)
This was the most stunning Pampas grass throughout late-autumn and winter with fluffy, airy plumes that caught the breeze, looking silver-white in winter sun. (2.4m x 2.5m)
‘Silver Feather’ AGM
A short variegated form with green and cream leaves, reaching 1m in height and spread. Silver-white plumes emerge late, but the foliage is pleasing all year. Used in my own garden. (1m x 1m)
A shorter Pampas grass with yellow, arching foliage bearing a few airy heads in buff and silver. (1.1m x 2.2m)
‘Sunningdale Silver’ AGM
Silver-white plumes held above the grey-green leaves and still the best large, impressive pampas. (3m x 2.5m)
Species from New Zealand
C. richardii AGM
Also used in my own garden, because this green-leaved New Zealander produces flowering one-sided awns in July. These persist until late-autumn. Likes some moisture and will flower in partial shade.
C. fulvida AGM
Another New Zealander with one-sided silvery plumes borne in mid to late summer on splaying stems. (1.2m x 2m) A little like an Afghan hound.