Plant of the month for September

Panicum 'Northwind' brings a breath of autumn with its delicate sprays of flower and colourful foliage

As September sidles by, ornamental grasses come to the fore, capturing the eye with their spectacular beauty. We use them to add late season interest and texture to our plantings through the autumn.

Panicles of Panicum 'Northwind'Panicum, otherwise known as switch or panic grasses, are well-behaved grasses that form attractive clumps (but don't spread invasively). There are many to choose from, but one of most distinct must surely be Panicum virgatum ‘Northwind’.

It's a particularly upright cultivar, reaching around 1.8m (6ft) with narrow, straight stems that a add great vertical accent to plantings. The foliage is quite wide and has a beautiful blue-grey colour; giving the grass a stunning appearance, particularly when it moves in the breeze.

Panicum virgatum ‘Northwind’As the months become colder the foliage turns shades of yellow, but it keeps its structure through the winter months, adding stature to the garden. The flower panicles of this particular cultivar are borne amongst the foliage at the top of the stems, giving the impression of a bouquet of flowers.

Panicums like to grow in an open sunny situation. They enjoy a well-drained soil that retains moisture during the summer and won’t tolerate extremely dry conditions. At RHS Garden Hyde Hall all our ornamental grasses are cut back in the spring so we can enjoy their movement during the winter period. They can also be divided at this time, although we've found many of them don't grow away vigorously again afterwards.

Panicum virgatum ‘Northwind’ is used to great effect in our Modern Country Garden. In a narrow border it adds fantastic height without spreading too much, and gives the boundaries of the garden a wonderfully soft feel. Simple blocks of plants interweave together to create dynamic combinations with year-round interest. In between them is Stipa gigantea whose golden, oat-like spikelets open before the panicums and emerge amongst their silvery foliage. For early season interest we use bergenias along the front of the border with Liatris spicata ‘Kobold’ woven between adding height with their pale mauve flowers in summer.

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