So, it’s still winter. During winter, deciduous trees have lost their leaves, and many perennials tend to just disappear underground entirely. But:
although winter may be cold and bare, it is necessary, and produces positive effects.
While it is both traditional and easy to see winter as an undesirable and unpleasant time of year, it has been with us for as long as… well, anything really, and it’s as natural as anything that happens in the (organic) garden. The fact is, most of our plants have evolved with the expectation of winter, and would experience considerable problems, were it to suddenly go away.
Any plant that isn’t evergreen will go through a dormancy period during the winter, and without this period of rest, plants can lose much of their vigour. Some plants require a period of cold in winter, in order to produce flowers and fruit during the upcoming season. This is called vernalisation. Biennials such as Digitalis (Foxgloves), and fruit such as Ribes nigrum (Blackcurrants) serve as particular examples of this.
Seeds often will not break their dormancy unless they have gone through a cold period, and begun to warm up in the aftermath. This is called cold stratification. The primula family, which includes Primula veris (Cowslip) and Primula vulgaris (Primrose), are an example of seeds that require cold stratification.
Several vegetables will grow significantly sweeter when they have experienced a cold period. To those of a scientific mind-set, this is because they use sugar to lower the freezing temperature of the water inside them, and prevent frost damage. Examples include; sprouts, kale, cabbage, parsnips, carrots, beetroots, turnips, and swedes.
Cold can act as a natural population control for certain pests and diseases. This doesn’t get rid of them for good, but without winter, their numbers would soar.
If you were to ask a random person on the street what makes an appealing plant, the chances are very high that they’ll say flowers. Question them a bit more, and you’ll probably move on to the subject of leaves. While winter won’t completely deprive you of these things, they do become in much shorter supply. This means that the winter appeal of your garden is much more tied up in the structure of plants. Deciduous trees and large shrubs are a good source of structural interest during the winter.
As with most aspects of the garden, plant choice is essential to generating winter interest. When it comes to winter colour, I find it hard to beat the bright stems of dogwood. Although dogwood is best known for the striking red stems best embodied by Cornus alba ‘Sibirica’ (Siberian Dogwood), Cornus sericea ‘Flaviramea’ (Golden-Twig Dogwood) is… golden twigged. Cornus alba ‘Kesselringii’ (White Dogwood) is… dark red in spring, and dark purple in winter (it’s named for its berries, not it’s stems). My personal favourite, though, has to be Cornus sanguinea ‘Midwinter Fire’ with its flame-like stems, which transform along their length from yellow to red (making it rather aptly named). Most dogwood plants will grow many green leaves in the summer, leaving the stem colour to peek out from between them. Helpfully, the plants aren’t particularly fussy about their conditions, although you should avoid letting them get very dry. The brightest colour is focussed on new growth, so it’s quite important to prune them back every spring.
Rubus cockburnianus is a very interesting and distinctive winter plant. Feel free to laugh at the name for a bit.
Done? Great! It’s a white-stemmed bramble, or blackberry plant, available in both deciduous and evergreen varieties. Like all blackberries, it is a vigorous grower, and thorny, making it something of a risk, but the birds will thank you (with their presence) for its shelter and fruit. It’s important to give it enough space, and keep it under control. It’s not a plant inclined to staying neat, and so will struggle to find a place in a more formal garden.
Mahonia is a winter-flowering plant that I especially like, I find the unusual shape of the Mahonia especially appealing. It stands out greatly in winter, when it is fully in leaf and flower, likely being surrounded by the bare branches of deciduous neighbours. Most varieties have bright yellow flowers that stand out like a lantern, growing in groups of pointed racemes. They are not at all difficult to grow, and cope well with pruning. Other winter flowering Shrubs include:
- Sarcococca (Christmas Box), which bears small, fragrant flowers, and maintains its leaves throughout the year.
- Lonicera x purpusii (Winter-Flowering Honeysuckle)
- Hamamelis (Witch Hazel) requires acid soil, and is scented
- Viburnum tinus is evergreen
- Viburnum × bodnantense ‘Dawn’ bears pink flowers on bare stems
- Erica, Calluna, and Daboecia (the three Heathers) usually require acid soil, although a few Erica will cope with neutral.
- Jasminum nudiflorum (Winter Jasmine)
Winter flowering Perennials and bulbs include:
- Galanthus (Snowdrops),
- Cyclamen coum,
- Eranthus hymelis (Winter Aconite)
- Helleborus (Christmas Rose).
Ornamental grasses serve as one of the few sources of movement in a winter garden. Since they are ornamental, a wide variety of colours and sizes are available, with varied flower shapes. Autumn colour is another major advantage of ornamental grasses. Although there are a wide variety of colours, the non-evergreens default to a neutral buff colour in winter.
Some plants have seedheads that can be left out in winter, for their attractive shapes. Examples of these include:
- Dipsacus (teasel),
- Papaver somniferum (opium poppy)
- Erynigum (Sea Holly)
- Acanthus (Bears Britches)
- Iris foetidissima
- Nigella (Love in the Mist)
- Roses with hips such as Rosa canina
- Monarda holds its shape well throughout the winter
- as does Phlomis
Evergreens have an important role to fulfil in the winter garden, bringing in continuity and structure, being often utilised for hedges and topiary. While Buxus sempervirens (box) is ubiquitous, it can suffer from the particularly tenacious disease box blight. Alternatives include Hebe, Ilex crenata (box leaved holly), Lonicera nitida (shrubby honeysuckle), Taxus baccata (Yew), Ligustrum (Privet) and Euonymus fortunei. The Christmas classic of Ilex (Holly), with its bright red berries and distinctively shaped glossy leaves generates winter interest. Its berries serve as a good source of food for birds in the winter, and the Christmas card image of a robin standing on a holly branch, is in fact completely accurate.
So no matter how cold it gets, stay positive; it’s all for a good cause!