| For people used to gardening in regions where the | | | | sometimes possible to grow evergreens like the |
| winters are freezing cold, the question of when to | | | | olive or many species of Acacia. |
| prune trees and shrubs is thought of more or less | | | | However in regions where the winter lows hover |
| in the following terms. Deciduous plants, that is | | | | around the 5c mark, typified by nights that are |
| those that drop their leaves in the fall, being hardy | | | | chilly but nonetheless frost -free, it becomes |
| to cold, should be pruned during their seasonal | | | | possible to grow a far wider range of garden |
| dormancy, i.e. the winter, whereas evergreen | | | | plants, including species that originate from |
| trees and shrubs, excluding conifers, to the | | | | sub-tropical and even tropical habitats. Examples |
| extent that it is possible to grow them at all in | | | | would include Delonix regia, Jacaranda acutifolia, |
| cold climates, are not touched until the spring, or | | | | Tipuana tipu and Peltophorum dubium, amongst |
| at least until all possibility of frosts has passed. | | | | many. |
| It is also known by many home gardeners and | | | | In such conditions, species belonging to this |
| presumably by all professional ones, that pruning | | | | category drop their leaves, not as a dictate from |
| deciduous plants in the spring can be highly | | | | their genetic code, as is the case with naturally |
| detrimental to the future health of the plant, due | | | | deciduous plants, but as a temporary response to |
| to the loss of sap that would result from pruning | | | | the relative cold of a Mediterranean winter night. |
| in the spring. | | | | And herein lays the trap! Many people on seeing a |
| However, for those of us gardening in mild winter | | | | tree of sub tropical origin out of leaf, unwittingly |
| climates, particularly in areas where frosts are | | | | mistake it for a truly deciduous plant, connecting |
| virtually unknown, the issue is somewhat more | | | | deciduousness with cold-hardiness. The trouble is |
| involved. In fact many a serious mistake has been | | | | that the precise opposite is the case. Conditionally |
| made because of a misunderstanding of | | | | deciduous plants are often or not highly sensitive |
| deciduousness and its implications. These mistakes | | | | to cold, and are therefore liable to be seriously |
| involve pruning a certain type of plant at the | | | | damaged by winter pruning. * |
| wrong time. | | | | So what can you do to avoid making such a |
| The phenomenon of leaf drop occurs in three | | | | mistake? In the absence of specific knowledge |
| main circumstances. One of these is when certain | | | | regarding this or that plant, the simple answer is |
| plants drop their leaves as a means of reducing | | | | to find out the natural habitat of a plant before |
| water loss during the hot, dry season. The leaf | | | | pruning it. This is a piece of information that most |
| drop that takes place though in cold climates is a | | | | people gloss over when they read up on any |
| genetically programmed response allowing | | | | particular plant in garden literature, but as I hope |
| broad-leaved plants to survive the freezing | | | | will be clearer now, it is information that can have |
| temperatures in the winter. It is a process that | | | | significant consequences for the future of some |
| starts towards the end of the summer, becomes | | | | of your trees and shrubs. Therefore, if a tree is |
| most obviously visible in the autumn accompanied | | | | out of leaf in the winter but is of tropical or |
| by often spectacular leaf colors, and terminates | | | | sub-tropical origin, it should not be pruned until the |
| at the beginning of winter with the actual fall of | | | | spring or the summer, together with the |
| the leaves. | | | | evergreen plants. |
| Gardeners in cold winter climates are naturally | | | | *Note: Plants that are liable to be cold sensitive to |
| restricted in the number of species available to | | | | any degree, can be seriously damaged by winter |
| them. Where temperature fall below -10c, it is | | | | pruning, as they have less capacity in the cold |
| highly unlikely that any evergreens, conifers | | | | season to resist the fungal and bacterial infections, |
| excepted, can be grown at all. In places where | | | | brought on by pruning cuts. |
| winter lows range between say -5c and -9c, it is | | | | |