What to do in the garden in December
Frost illuminates the garden
In winter, some plants look even better such as grasses, a severe frost will illuminate the ornamental grasses - follow this link to see how good grasses look in winter shimmering with frost illuminated by a low winter sun. The frost on the fronds of grass are just spectacular, many plants are impressive when touched by frost as the images above show.
Winter Gardening Tips
Wind Rock in roses can be a problem in the winter, especially the taller varieties. Strong winter winds can cause the rose to shift about in the wind, which creates a gap where the stem enters the soil. This gap can get bigger as the plant moves about in the wind, which allows water gets in around the stem, and then to freeze. It is possible to reduce the plant's vulnerability to "wind rock" by pruning the stems down by around a third. Only prune roses during a mild spell otherwise it is possible the frost may damage the growth bud below the cut and cause die back of the stem.
Winter protection is needed for non hardy plants if they are not fully hardy and follow this link for an explanation of Frosty Hardy. Popular examples of shrubs which are not fully hardy are Olive trees a Mediterranean shrub sold in various retail outlets and whilst Olives, especially once established will tolerate a significant level of cold, but not a prolonged spell of low temperatures which we often experience. Olives are ** hardy as is Laurus nobilis, common name Bay, both of which are increasingly grown in containers. Some varieties of Agapanthus, Escallonia, Herbs are not fully hardy, and need winter protection under glass.
To ensure winter survival, it is best to bring the plants in under glass and raise the container so it is off the ground by inserting feet or raising on bricks. If overwintering outside it is important to wrap the container with something insulating, bubble wrap, Hessian, or old jumpers and if its going to be very cold, cover the plant with a fleece. It is equally important to remove the fleece when the cold spell finishes to ensure the plant gets plenty of air circulation. Plants covered all winter, or covered up for too longer spell often get damp and rot which means it is best to limit cover to the cold spell.
As this image illustrates, a bout of severe weather can cause damage. In most winters there is a chance of a severe frost at some time and a good tip is to disconnect the water-butt and drain it to avoid the risk of splitting the water butt as the residual water freezes and expands. Evidence of an expensive mistake.
Winter can be a good time for weeding. I often find that the battle against the weeds has been lost by the end of the summer, especially as plants are so lush the weeds are hidden and only fully revealed as the time comes to clear the borders. After a frost is a good time to weed; the ground yields the weeds more easily.
It is good to look forward to Spring and Forget-me-nots (latin name Myosotis) often get a bad press as a zealous self seeding cottage plant. Bad press or not, forget-me-nots can offer much welcomed early spring colour and look fantastic with spring bedding and in a natural setting along side a stream in a semi wild patch.
For the best spring display of Forget-me-nots is a good time to thin out the plants. Forget-me-nots do self seed a lot, and if they are growing too close together, Forget-me-nots are prone to get mildew which can spread to ajoining plants. One year I didn't thin them out and they overcrowded other plants, and severely damaged a clump of Hellebores. It really is important for the health of the forget-me-nots and the plants around them that you thin them out in late autumn or early winter.
Damage to lawns
It's really true that walking on the frost frozen grass does cause damage. When frozen, the leaves become brittle, and will not yield to pressure, and so snap and break when trodden on in frosty conditions. The image left shows where the grass has been walked on and will leave brown marks where the grass is damaged, which look unsightly in the spring and the damage will make that patch more susceptible to disease.
Given how hard it is to create a decent lawn its worth resisting walking on it during the very cold weather.
Snow damage to Shrubs
It really is a good tip to knock snow off shrubs when there has been a heavy snowfall. I used to think this advice represented an abundance of caution, making work for work's sake, until we had a really bad winter with heavy snow and several shrubs were badly damaged. All shrubs are at risk, but those with the more open crowns are most at risk. What happens is the snow piles into the open centre of the shrub, which forces the branches out, until they snap. Also the snow weighs down the branches, freezes to the ground bending branches over until they snap.
Heavy snow will snap the branches of even mature shrubs. If this happens, all you can do is prune the shrub but it may never regain its shape if severely damaged. A good tip for snowy weather: get out there as soon as you can with a soft broom and brush snow off the tops and loosed branches tied down by snow which will save the shrub, and money if you have to replace it.
This Elaeagnus in the image has been devastated by snow damage and many branches had to be pruned and cut away. The sheer weight of the snow had bent the branches, some touched the ground and held down by the snow, and more snow. Finally the branches snapped, even mature branches, leaving no choice but to cut them off completely; snow pruning a new experience. Snow is far more destructive than it seems.
Hellebore black spot
Hellebores are a lovely late winter and early spring flowering plant which are easy to grow and will tolerate some shade.
Tips on growing Helleborus and images of many varieties of Hellebore