November: Ornamental Grasses

Ornamental grasses are not everyone’s choice, they have a reputation for self-seeding and getting too invasive but there are some that are well behaved and would enhance an early winter garden by adding colour, form and movement.

One such is Stipa gigantea or the Giant Feather Grass. This is a very striking evergreen grass that forms a low spiky mound of arching narrow deep green leaves. In time it will make a large clump, around 4’ across. In early summer Allium ‘Purple Sensation’ complements the foliage as would the purple flowers of one of the hardy perennial salvias such as Salvia x sylvestris ‘Mainacht’ (May Night) or the low growing Verbena rigida.

Then in mid summer a huge sheaf of very long-stemmed, oat-like flower-heads erupts in mid-summer, up to 6’ high. When mature, these splay apart to make a wide fountain shape that almost hides the plant. The seed-heads dry out naturally on the plant and persist into early winter, where they make a good architectural feature, especially when outlined in frost. These can look very good in early winter, particularly if the frosts have been kind and there are still some Verbena bonariensis flowering nearby, until the autumn winds blow the heads over This grass has never self-seeded for me and to propagate divide plants from mid-spring to early summer. It needs well drained soil in good sun.

A completely different but equally striking grass is Calamagrostis x acutifolia. There are a number of cultivars including ‘Karl Foerster’and ‘Overdam’. Karl Foerster make a strong vertical form, particularly noticeable in winter as it stands upright as a tall stiff column of bleached straw coloured stems, it takes a lot to blow these over. It is a small grass than the Stipa, making a clump around 2’ across but 5-6’ tall. Again this grass will not self-seed but needs to be divided and also needs well drained but good soil in sun.

A word of warning it you don’t like grasses that self-seed. Beware others in the same genera such as Stipa tenuissima, which is a wonderful small shimmering grass but it does seed around quite freely. Likewise Calamagrostis arundinacea, again a lovely medium sized grass with arching clumps of fine foliage with trailing flower heads – in winter the foliage develops tints of red, orange and yellow but this one will also self-seed, although not as freely as the stipa.

CAF