Christmas plants offer excellent value for money, especially as most kinds can be kept going for more than one year with a little extra effort, and some knowledge. The most popular Christmas plants are poinsettia, azalea, cyclamen, winter cherry, hyacinth, Christmas cactus and chrysanthemum.

In more recent years, some others have become more widely available and more popular, such as anthurium, winter begonia, ardisia, hippeastrum, jasmine, kalanchoe and peace lily, although these are sold at other times of the year too.

The Christmas plants will thrive if their basic needs of water, light and warmth are met. Feeding is not needed at this time of year, but must be given during the growing season from April. The most important aspects now are watering and giving the plant the right degree of warmth, not too much and not too little.

Poinsettia flowers for Christmas naturally because of shorter day length from September. It must be kept in a heated room. Most rooms will easily achieve the required temperature, but temperatures can drop during the night and certainly would do so behind curtains.

Poinsettia often drops its leaves soon after it comes into the house. This is usually caused by the plants being chilled. Do not buy houseplants that have been left outside in the cold and do not over-water, just moisten.

Christmas cactus is a ‘forest cactus’ from tropical forests, growing in the leaf litter. It does best with even watering, never standing in water. It is usually grown on a window sill indoors. It does not need a warm room but flowers more reliably for Christmas if the room is warm. Flowering is triggered by short days in early autumn. Artificial light can prevent flowering.

Christmas azalea, indoor azalea, or Indian azalea, makes an excellent long-lasting and long-flowering house plant. It is not hardy and cannot be grown outdoors except in very mild areas, but it does not need as much warmth as poinsettia and can be grown successfully in an unheated greenhouse.

Q&A: Am I pruning my trees correctly?

The birch tree. \Gerry Daly

Having pruned trees tight to the stem for many years, I have recently been told that this flush pruning was incorrect. Should I leave the branch collar intact? - P Doyle, Kildare

Leaving branch collars in place is now well-proven to be better with quicker healing, less disease rot, and better visual results. It is easier to carry out. The branch collar varies between different species of trees and is very obvious in some, including the birch tree (pictured left).

This was research work carried out in the United States by a man called Alex L. Shigo (8 May 1930 – 6 October 2006) a biologist and plant pathologist with the United States Forest Service. His large body of primary research serves as a broad foundation for further research in tree biology. He was the first researcher to cut tree trunks and reveal how the tree is structured internally. This has been the focus of a complete change of practice.

To-do-list

Fruit, vegetables and herbs

Not a week generally when much gardening gets done, but if the humour takes you, there are plenty of possibilities. Fruit tree pruning can be carried out during this period, except on plums. Fruit trees and bushes can be planted if the soil is not too wet.

Trees, shrubs and roses

Check that young trees are not developing bad forking habits and remove one side of a fork if necessary. It is easy to see these problems now that the leaves are gone. Delay tree planting if the ground is very wet. Roses can be pruned at any time.

Lawns

Lawns tend to be very soft at this time of year and it can be very damaging to the soil structure of a lawn to walk over its surface when it is wet, but if it is dry enough, carry out a once-off mowing to neaten it.

Flowers

Put out a few pansies or cyclamen for a bit of seasonal colour in containers or use some evergreen plants to give life to the garden close to the house entrance. If the ground is wet, do not undertake division and re-planting. Many flowers react badly.

Greenhouse and house plants

Lots of seasonal house plants are bought as gifts but soon succumb to draughts, too much heat, lack of water or too much water. Read the label and try to accede to the conditions. Plants last better in cooler rooms with good light.