Useful for this purpose are cull bracken fronds, long straw, dead tops of herbaceous border plants (suchaefl Michaelmas daisy) or the cut branches of evergreens (such as laurel and I cypress). This material can be held in place by a few stout canes and if I severe weather is forecast in January and February it may be desirable to I provide additional cover with hessian or polythene.broad sepalled sky-blue 'Perle d'Azur', for these are very telling when seen against the silvery leaves of the broom and will produce flowers until the autumn. Prepare a site for the clematis a little away from the host's roots. To provide a display in autumn on our south or west wall, there is no better plant than Solatium crispum 'Glasnevin' (syn. S.c. 'Autumnale'). This is the best form and a spectacular plant, producing 6in(i5cm) wide clusters of purple-blue flowers with bright yellow stamens. This Chilean climber is remarkably hardy, semi-evergreen and appropriate for a tall wall or fence, or for scrambling over a shed or similar structure. Equally effective and less frequently planted is the evergreen Escallonia Tveyi', (E. bifida*.E. exonien-sis). Its large, handsome, dark green foliage makes the perfect background for the large panicles of pure white flowers which attract butterflies in the autumn. This is a large shrub, but it adapts well to wall cultivation. As a winter-effective subject for this aspect and for all soils, including chalky ones, we could consider Chimonanthus praecox, the winter sweet. It is grown primarily for its sweetly scented flowers produced in open weather during January or February on the leafless branches. A medium-sized shrub, this needs pruning back immediately after the flowers fade to ensure that it retains a compact habit. 'Grandiflorus' is the best form with deep yellow cup-shaped flowers with a prominent red or purple stain, while f. luteus has larger, unstained, translucent pale yellow flowers which open a fortnight later than the type. As this shrub is not effective during summer, it is best to use it to provide support for one of the many large-flowered garden clematis such as the reliable purple-blue 'The President' or 'Ville de Lyon', the best of the reds, which often flower from July to October. Lofty walls, often at the gable end of a house, frequently incorporate a chimney which, if in use, will give off warmth to foster the tender climber or wall shrub. If such a wall is south- or west-facing, there is a grand opportunity to grow vigorous, often spectacular plants which would be unsuitable for growing against lower walls, probably incorporating windows. Most plants of this kind need plenty of room, and if more than one is planted they should be at least 8ft(2.5m) apart. Again, with regard for seasonal effect, the choice could be made from the following, assuming the availability of a sunny wall and fertile, well-drained soil.