December is traditionally one of the quieter months in the flower and vegetable garden. Winter vegetables really come into their own now, especially once parsnips and Brussels sprouts have had a frost or two to improve their flavour. While most spring-flowering bulbs should already be in the ground, there is still time to plant tulips, which actually benefit from this later planting. Many are well suited to growing in containers too.
Remove all plant debris from round the garden or on the allotment, as fallen foliage and the like encourage pests and diseases to over-winter and cause us problems next spring and summer. This is particularly important if you grow roses.
If you made a sowing of sweet pea seeds back in October and have them in the greenhouse or a cold frame, pinch out the growing tip after two pairs of leaves have formed; this will encourage the development of side-shoots and bushy growth through the winter, and stop the young plants becoming 'leggy'. They will then make steady progress and be ready for planting out early next spring.
House plants make attractive features through the dark winter months. The compost of azaleas should be kept wet, but never saturated. Poinsettias, on the other hand, should have compost which is only just moist. If you are yet to buy these Christmas favourites, always choose plants from stock which has been kept in warm spot indoors in a shop; never buy plants from outside, as they will not thrive when you get them home, and may well die.
Where containers planted for winter displays are close to the house or other buildings, check them regularly to see whether they are receiving enough moisture from rainfall. If not, water them to prevent the compost drying out. It can be easy to forget them at this time of year because they tend not to need as much watering as summer containers.
Keep a look-out for pale blotches and grey mould on the foliage of violas and pansies, as these are the symptoms of downy mildew. The affected leaves will gradually die. Unfortunately, there is no chemical treatment. Remove infected leaves as soon as the discolouration appears.
If the weather remains relatively mild this month, you may see that some spring-flowering bulbs start to show above ground. In fact we have noticed this happening already! There is no need to be concerned about this because, as the weather becomes colder, their rate of growth will slow accordingly and they will still flower when we expect them to.
May we remind you that it is not too early to order seed potatoes, especially if you are keen to grow particular varieties. We begin despatch from January 2017 onwards. Please have a look at our new varieties. Elfe is a second-early with yellow flesh and a rich, almost buttery flavour; it's really great for making mash or for baking. Gemson is another second-early, and we recommend this for its large crop of smaller tubers. It boasts the famed Maris peer as one of its parents, and has excellent disease resistance. The tubers have a firm, creamy flesh, and are perfect for steaming, boiling and as a salad potato. White and pink-skinned Pink Gypsy is a maincrop, and this one is particularly versatile, being superb for mashing, baking and roasting.
If you enjoy growing large onions, whether for the kitchen or for the showbench, do consider trying our new variety called, simply, Exhibition; this splendid strain was bred in East Anglia from The Kelsae, the most famous of all onions. It produces large, flask-shaped bulbs with a golden skin colour and a deliciously mild, sweet flavour. It can reach 454gm (1lb) in weight with very little care, but considerably larger specimens are achievable with a little 'TLC'. Seed of Exhibition can be sown in gentle warmth from December through to February. It's well worth growing!
Now is a good time to dig over any part of the vegetable garden or allotment which is not in production. This is best done when the soil is not too wet and certainly never when it is frozen. Dig to a spade's depth (a spit), and leave the soil in clods as it falls to be broken up by frost and rain action in the weeks ahead.
Autumn-fruiting raspberries can now be pruned back virtually to ground-level. This will allow next spring's new shoots to develop strongly, allowing them to flower and fruit next autumn. If you like the idea of some summer raspberries from the same plants, leave two or three of the strongest canes tied into the framework, and these will provide you with some tasty summer berries ahead of the autumn harvest.
This is the best time to give fruit trees and bushes that have been subject to attacks by pests such as aphids a spray with a 'winter wash'; this should see off any over-wintering pests and their eggs. Modern winter washes use surfactants and natural oils, rather than being tar-based like the old-fashioned remedies. This treatment should mean a healthy start to next year's growing season. Winter washes are available to order from our web site or all good garden centres.