Architectural Plants. Christine Shaw

giving weight to the argument that it is not a separate species.

      Another form worthy of special mention is Trachycarpus ‘Breppo’. It’s not often seen, but worth hunting around for. The leaves are large, beautiful and fairly stiff, but it’s the trunk that gives it a superior look. It is stockier than that of Trachycarpus fortunei, and the trunk hair is made up of much longer and fluffier tresses. Removing this would be a pity.

       Washingtonia filifera

       Cotton Palm

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      The white threads of ‘cotton’ contrast well with the thick, sturdy trunk.

      A splendid palm tree with huge fan-shaped leaves of vivid green. The fingers of each part of the leaf are tipped with white threads of ‘cotton’, which hang down from every frond, giving a graceful feel to the whole plant.

      Named in honour of George Washington, Washingtonia filifera is native to California and all south-western parts of the USA. It is used heavily for municipal planting and is easily recognizable by the thatch of old leaves that hangs down vertically to cover the whole trunk. However, these old brown leaves are considered a fire hazard in some areas, and their removal by brown-bitting is becoming more commonplace. Seeing the clean stout trunks with a head of lush green foliage is a huge improvement on their appearance.

      As it is a desert palm, Washingtonia filifera can cope very well with hot, dry atmospheres, making it an excellent choice for an atrium or a large conservatory. Its speed of growth and eventual size of at least 9m (30ft) even away from the desert mean that planting in the ground is by far the best option. When planning their conservatories, some gardeners leave planting spaces in the ground for such plants. If it really has to be grown in a pot, make sure it is a massive one. This palm takes around fifteen years to attain a height of 3.7m (12ft) but then it can speed up and become unmanageable very quickly. Large palms are far too heavy to keep repotting easily. However, this palm is so beautiful, it is tempting to buy one, grow it for ten years and then worry about what to do with it when the time comes.

      Growing young plants from seed is very easy and quick. Observing the root system on even newly germinated seedlings will tell you that this palm is used to finding its own water supply: the tap root is about five times longer than the leaf section. But this drought-resistant quality applies only to plants growing in the ground – container-grown specimens must be watered regularly during the growing season.

      Full sun is an essential requirement, too. The only maintenance needed is frequent inspections for red spider mites.

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      Delicate ‘cotton’ filaments cover the edges of every leaf.

Ferns

      Ferns are delightful additions to any garden. They do not flower, but their wide variety of leaf shape and their different shades of green bring something special to planting schemes.

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      The foliage of Pteris cretica consists of delicate evergreen ribbons.

       There are hundreds of different ferns generally offered for sale, but this chapter concentrates on the few that could be described as the most architectural, either because of their size and shape or because they are evergreen. All ferns have a certain presence and charm, but those giving year-round colour obviously have more benefit in the garden.

      There are several categories of evergreen fern discussed in these pages. There are Tree Ferns such as Dicksonia antarctica and Dicksonia squarrosa, which have such a stately and imposing shape that they could easily be planted as single special specimens in any garden. Then there are the smaller ferns such as Pteris cretica and Blechnum spicant, which look especially effective in large numbers. There are also large, low-growing ferns such as Blechnum chilense and Polystichum munitum, which look fine planted singly in smaller gardens but would look very impressive in groups if you happen to have the luxury of larger grounds.

      Ferns enjoy moist, shady conditions in corners of the garden where there is little wind and high humidity. They love being on sloping ground, where the water can drain away immediately without collecting around the roots. Although they need plenty of moisture, boggy places are not suitable.

      Ferns are easy to maintain. They need little extra food, and pests and diseases are rare if the cultivation notes are followed. This is just as well because the foliage of ferns is often too delicate to cope with being sprayed with chemicals. If anything is found nibbling on ferns, it is better to remove the problem manually, as insecticides often cause more damage than the bugs.

      A whole new language has been constructed around ferns, and some of the terms deserve explanation. The leaves are referred to as fronds. The new season’s growth is tightly coiled up before gradually straightening out as it matures, and its curly stage is rather imaginatively referred to as a crozier (think of the large metal crooks, or staffs, brandished by bishops when they are in full regalia). Ferns don’t have flowers or seeds or seed pods. They are propagated from spores, which is powdery dust contained in little sacs called sori. There are also fern societies to join if you’re really keen, and these are referred to as pteridological societies. Unfortunately, I get the word pteridological mixed up with pterodactyl, which conjures up all sorts of mental images of the people attending their annual meetings.

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      Dicksonia antarctica adds a loud presence to any fernery.

      Some fern collectors take their hobby as seriously as stamp collectors, delighting in obtaining as many different types of fern as possible. This is fine for a botanic collection, but no use at all for the amateur gardener or landscapes Ferns look so much better if planted out in larger numbers. The effect is far more dramatic if ten of the same fern are planted together, rather than one each of ten different species.

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      Polystichum munitum is tough enough for the coldest of gardens.

       Most ferns prefer to be planted in areas of the garden where many other plants refuse to grow, which makes them useful as well as desirable.

      This group of plants adores soil containing lots of peat. The light texture suits their root systems admirably. With the natural sources of peat being stripped away, it seems irresponsible recommending such material. But, having tried many peat substitutes, there is nothing as good as the real stuff – not yet, anyway. Hopefully, this is something the compost industry is working towards. It would be wonderful to find something that is as cheap and pleasant to use, produces excellent results and doesn’t have to be shipped from halfway around the globe using fuel-hungry means of transport.

      The propagation of ferns is a tricky subject. Some ferns such as Asplenium scolopendrium conveniently form clumps as they mature. These can usually be divided up to obtain extra plants. Others such as Woodwardia radicans form baby ferns on the upper surface of mature fronds. These fronds can be pegged down over compost until the babies have formed their own root system. They can