Winter Proofing tender shrubs and climbers

Like many of us you no doubt covet the more exotic species and certainly many of the less hardy shrubs and climbers are relatively easy to care for on a sunny patio. Just because they are less frost hardy doesn’t make them more difficult as a rule. However, now we come to the sticky part. As the temperatures get colder and the threat or more severe frost or snow increases week on week, provision should be made to protect these treasures over the coming months. Just some of the species which might be affected include: Agave, Aciphylla, Acacia, large-leaved Hebes, Carpenteria, Sollya, Dodonea, shrubby Salvias, Piptanthus, Feijoa, Mandevilla, Oleander, Datura, Tea-Tree, and Freemontodendron. Assuming you have a cool greenhouse or conservatory now is the time to bring them in. At the same time, look them over; if there is any diseased or dying growth then remove it now. If there is evidence of disease or bugs then it should really be kept isolated, the problem rectified, or, as a last resort, leave the infected plant outside! You don’t want the problem to spread to other plants. Now is NOT the time to re-pot. To re-pot now will mean the roots will ‘sit’ in cold, wet compost until next Spring and the mean temperature at root-level will be lower. The roots won’t be active or grow now until the Spring so even if a plant appears pot-bound, leave it be. Similarly there is no need to feed now as the plants won’t have any nutrient requirements until growth re-starts next year. To protect against very severe frost [last year we have consecutive nights of minus 14 degrees here in Norfolk] which might even do damage in the confines of a greenhouse, wrap the pots in -newspaper or even better, horticultural thermal fleece. The latter is comparatively expensive to buy, but it can be re-used for many years if looked after. During mild spells and the middle part of the day if it is very sunny to remember to ventilate by opening one or two windows or the door. It is important to maintain good air circulation to prevent moulds and diseases. Lastly do not overwater your prize specimens. Most will be happier on the dry side and this will again prevent frost damage over winter. Water only if dry or foliage starts to become limp. When to move them out? This is a tricky one and will depend on weather conditions at the time. Ideally move them out before active soft growth starts but keep an eye on the weather and make sure they aren't caught out by any heavy late frosts of snow. If you make the mistake and leave them indoors too long and new growth starts, then you must wait until all fear of frost has passes in May before moving the plants out, because this new growth will quickly blacken if frosted because it will be ‘soft’ and not hardened. Now you can re-pot and feed your plants and start watering liberally again, as your prize specimens grow ever bigger and more effective, await your exotic display once again in the Summer even better than the year before. Plants in the ground If you have any slightly tender or 'iffy' plants that are growing in the ground that can't easily be moved indoors, then you can still give added protection with bubble warp, horticultural fleece, or even straw spread thickly around the base of the plant will help. Don't use any polythene sheeting or plastic products to protect your plants, plastic and polythene is a terrible insulator and may actually make things worse. Don't be tempted to cut back any growth as this will give added protection. Save any pruning or trimming until next Spring. These tips can equally apply to hardy fuschias, caryopteris and Cistus which may normally prove hardy but can be susceptible during extreme winters. It's better to be prepared as they say. Pictured are the exotic chalice shaped blooms of Freemontodendron californicum. Although generally hardy on a sunny south or west wall it will need protection elsewhere, especially younger plants.