Evergreen Ferns - refreshing even the darkest corner of the garden - by Sally Gregson Autumn comes, and goes.The bonfire colours blow away. The herbaceous plants shrivel back to the ground. And a few brave, late-flowering perennials lift the spirits. But it's that fresh bright green that's missing the most. Most evergreens: yew, holly, viburnum; seem sombre. Dark foliage provides an excellent foil to summer plantings and a strong skeletal structure in winter. But evergreen ferns refresh the darkest of corners with their airy, graceful fronds.  Most ferns, though by no means all, prefer shade. Some of the larger-leaved evergreen ferns such as Polystichum munitum are very tolerant beings. They will grow in dry shade under trees, and, providing the soil holds a little moisture, these will also survive in sun: their fronds are tough and not too lacy.Many species in the genus, Polystichum are very useful in the drier shade under trees. P. setiferum in all its manifestations generally makes a 60-75cm (2-21/2ft) fan of beautifully divided fronds. The variety P. setiferum 'Bevis' is particularly renowned for its delicately laced leaves and P. setiferum 'Divisilobum' has laddered fronds that are well-structured and architectural. A group of either planted underneath roses or any other deciduous shrubs, forms a petticoat that stays concealed in summer, and then becomes a lacy green frou-frou once the legs of the roses are bare. The Hart's Tongues (Asplenium scolopendrium) are especially tolerant of dry shade. Perhaps it's the shape of their eponymous leaves that renders them less susceptible to frazzle than most other ferns. They grow out of stone walls and along dry woodland paths in the UK, so they won't turn a frond when asked to perform under your apple tree. And there are some lovely forms that have been selected over the years. The leaves of Asplenium scolopendrium 'Cristatum' are widely crested at the tips like fat babies' fingers. And planted en masse, the wavy edges of A. scolopendrium 'Undulatum' create a stormy sea of green. They would look very effective flooding the ground under silver birches. Their smaller cousin, Asplenium trichomanes, the Black Spleenwort, grows wild in the nooks and crannies of old brickwork and within the dark damp interiors of Victorian grottoes. Their bright green leaflets on wiry black stems glisten mysteriously in the dense shade. If you plant them at the top of the wall, with luck the spores will wash down and find new homes of their own to germinate and inhabit. It pays not to be too assiduous with the weeding.  At the other end of the scale, it makes a strong statement in the most unwelcoming of corners, be it dry, dusty or dark. In the same genus, Dryopteris erythrosora, is less tolerant of drought. It needs shade, but it prefers more moisture. Its epithet, The Autumn Fern, is perhaps a little misleading. It refers to the colours of the new crosiers that slowly unfurl from coral pink to tan brown, before they mature to a shining light evergreen. The Autumn Fern seems to prefer slightly acid conditions, so it would be worth piling leafmould around the crown as a mulch on alkaline soils.But evergreen ferns are not really ever-green. True, they hold their leaves well during the winter, but once the milder weather comes along and the new young crosiers start to push up from the middle, the over-wintered leaves begin to look very tatty. So before spring really gets underway it's worth tidying them up, cutting off the old leaves, and allowing all those bright, fresh green fronds to reclaim their shady haunts for another year. |