Architectural Plants. Christine Shaw

specimens produced from spores, virtually all those sold commercially are imported from New Zealand. They usually arrive in huge quantities packed into containers and shipped across to retailers who are eager to get their hands on large, mature plants. Unfortunately, these fabulous plants are not as hardy and easy to grow as is often implied, and around 90 per cent of them end up dead, which is a sad end to something that has been growing happily for fifty or so years in its native country. Before buying a Dicksonia squarrosa, please spend some time thinking about its growing requirements to ensure that it has more than a sporting chance of survival.

      A perfect soil mix would consist of peat (or peat substitute) with some leaf mould and silver sand mixed in, but most types of light, well-drained soil would be okay. Avoid very chalky soil, not because it particularly hates alkaline conditions, but because of this soil’s inability to retain enough moisture. A quiet, shady, humid position, sheltered from wind is essential. Leave enough space around it for the fronds to spread out fully without touching anything. Keep the soil just moist. Humidity is vital, not just for the leaves, but also for the trunk, which should be sprayed regularly in hot weather. This fern could be kept in a large pot for many years, but much better results would be gained from planting directly into the ground. Pour diluted liquid feed into the top of the trunk every month throughout the growing season.

      Leave propagation to the experts. Pests and diseases do not usually cause problems. Unless your garden is very mild, winter protection will be necessary. Use exactly the same methods as described for Dicksonia antarctica.

       Polystichum munitum

       Western Sword Fern

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      This evergreen fern is so hardy that it has even been seen growing in parts of Alaska, which sounds almost unbelievable.

      Another huge fern that is evergreen and fully hardy. It grows in the traditional fern shape, resembling a massive shuttlecock bursting out of the ground. Long, leafy fronds can reach 90–120cm (3–4ft) if the growing conditions are perfect. The spread of each plant can also reach the same dimensions.

      These massive ferns look wonderful if planted as giant groundcover beneath moisture-loving trees such as Eucalyptus aggregata or Eriobotrya japonica. The effect looks very natural, as it would in any jungly environment where the ground is usually totally concealed. The canopy of the trees would provide enough shade to keep any fern a good healthy colour.

      A sloping site is preferred so that any rain can immediately drain away without collecting in puddles around the plant’s base. Waterlogging would quickly lead to rotting, but ample supplies of water are essential to keep this fern happy enough to reach its maximum size. A site on a shady riverbank or by a pond would also make a good planting position. This plant must be kept out of the wind, which is true of most ferns, but particularly of larger ones. Also, avoid planting where people might brush past the foliage, as this is not something that will improve its appearance.

      Make sure the soil is light enough to enable the roots to penetrate easily. Peaty soil on its own is not enough to retain adequate supplies of moisture, and very light, poor soil should be enriched every spring. Either use large quantities of leaf mould or spread well-rotted, crumbly manure throughout the surrounding area.

      If moisture is allowed to gather in the crown during the colder months, the fronds can become discoloured with fungal disease, which eventually leads to rotting. Spraying with fungicide should be avoided. Instead, chop the whole lot down to the base and let it start again. The following season, it will grow like mad and produce masses of new croziers. By the end of the season, its former glory will have been regained. This treatment can also be adopted if it has been allowed to dry out and the fronds have become tired and brown.

      Propagation is best left to the experts. Apart from the fungal problems already mentioned, pests are not usually a problem.

       Polystichum polyblepharum

       Polly-polly

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      The fronds of Polly-polly have a lovely glossy sheen to them.

      A fern with such a ridiculous Latin name, I was tempted not to include it. But it is such a pretty plant and so popular that it couldn’t possibly be omitted. It is quite a small fern, growing to no more than 6ocm (2ft) in height and width. The fronds are dark green in colour and have a lovely sheen to the upper surface. Their glossy finish makes them very noticeable.

      Forget about planting just one or two of these ferns – they must be planted in large swathes for maximum effect. Large groups of the same type of fern always look more natural. The effect is far from boring. In fact, it looks restful and serene.

      This Japanese native fern enjoys the usual requirements expected of this group of plants. Light, crumbly soil with some leaf mould added to provide moisture retention and nutrients is ideal. A shady position is best, and shelter from strong drying winds is essential. It has no special requirements as to soil acidity, but avoid very chalky or sandy soils, as these tend to be too thin and well drained to satisfy such moisture-loving plants. Polystichum polyblepharum should never be allowed to dry out. It needs a constant supply of water that can be allowed to drain away almost immediately. Water collecting around the roots or crown of the plant can lead to rotting.

      Annual feeding is not normally necessary, but very poor soils can be enriched with more leaf mould or some well-rotted manure that has reached the crumbly moisture-free stage. If just a few ferns are being added to a place in the garden that is already planted up, they will have to be happy with whatever soil is there. If whole new areas or borders are being planned, then it is better to enrich all the soil thoroughly before any planting begins. If the soil is heavy, then dig in lots of peat or peat substitute to help with the drainage and to lighten the soil texture. If the soil is poor or very light and sandy, digging in lots of extra loam will help retain moisture and provide nutrients. Finish off by digging in either small amounts of manure or heaps of leaf mould, which really is as valuable as gold dust from a fern’s point of view.

      Propagation is by using the dreaded spore method. Pests and diseases are rarely a problem.

       Polystichum setiferum

       Soft Shield Fern

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      The lovely arching shape of each frond gives the whole plant a very architectural quality almost unmatched in the fern world.

      This European fern’s appeal in both looks and size creeps up slowly on unsuspecting gardeners. For the first couple of years, it is a perfectly satisfactory addition to any garden. It is a fine evergreen fern that is well suited to those damp and shady corners that can sometimes be a bit of a challenge.

      By year number three, it starts to get much more attention during the daily promenade around the garden. With the arrival of year number four, it suddenly becomes one of the most beautiful plants in the garden. By this age, its spread is almost 90cm (3ft) across. Its massive fronds unfurl out of tightly rolled-up fluffy, white balls, which are attractive in their own right. Each frond is very finely cut into a delicate filigree pattern. It is usually during late spring in its fourth season that you suddenly wonder why you didn’t plant loads more.

      There are masses of cultivars of this fern; some of the ‘Divisilobum’ and ‘Plumoso-divisilobum’ ones are particularly attractive with lots of soft, feathery fronds, which