Assessing winter damage
Once the worst of the winter is over, it is worth taking a look around your garden to spot problems and assess the impact of the cold, wind and wet, says Alan Titchmarsh
High winds, winter wet and severe cold snaps can spell disaster in the garden. So it’s a good idea to take a look around your plot, at the earliest opportunity, to assess any damage and take the necessary remedial action. Trees and shrubs can suffer broken stems and branches, or even be uprooted in a gale, while sever cold can cause bark to split, even on well-established specimens. Heavy falls of snow can bring down climbers and cause evergreens and hedges to become out of shape, while severe frost can kill young and borderline-hardy plants. Although most plants will survive prolonged periods of wet weather, if the soil remains waterlogged, it can be a killer.
Assessing winter damage
- Uprooted trees and shrubs
- Broken branches and split bark
- Misshaped evergreens and hedges
- Frosted flowers and scorched foliage
- Rotten alpines and winter disappearances
- Dieback of shoots and stems
Cold Since the last severe frosts of the spring are often the most destructive - damaging new growth, flowers and tender new plants – action now could save you a lot of money and avoid disappointment. Tender bedding plants and vegetables should not be planted out until after the last frost (usually mid-May in the south and a month, or so, later in the north). But if a late cold snap is forecast, they can be protected after planting by covering with sheets of newspaper, upturned pots or garden fleece. Tender emerging shoots of new potatoes can be safeguarded by drawing up soil over the shoots from either side of the row – known as ‘earthing-up’. Alternatively, err on the side of caution, by starting tender plants in pots indoors and delay planting them out to avoid unseasonably late frosts - see Sow early veg in pots.
Borderline hardy plants, such as hardy fuchsias, passion flowers and the potato vine, can have all the top-growth cut back to ground level by severe cold and the plants may even be killed. You can help prevent penetrating frost damaging the roots by covering the ground around the plant with an insulating duvet of leaves or chipped bark held in place with netting. The damaged top-growth can be pruned back during early spring and, new shoots should sprout from below ground once the threat of frost has passed. Borderline-hardy evergreens, such as rosemary and choisya, can have the top-growth killed, too, but these are unlikely to survive. You can check to find out the extent of the damage on all dead-looking shrubs and climbers by scraping a small sliver of bark off each affected stem – if it is green underneath, leave well alone. If brown, prune back to a healthy shoot lower down. With luck, you will be able to save the plant.
Don’t be hasty to unwrap protected plants, since damaging cold spells can occur throughout March and April. However, make sure you inspect them from time to time to check the protection is still in place and, if growing in containers, whether the plants need watering.
Even perfectly hardy plants can be damaged during later spring when a mild spell is followed by a cold snap. Shrubs, such as pieris, hydrangea and weigela can be lulled into producing new growth that’s easily scorched and disfigured if the weather turns wintry again. The flowers and buds of camellias and magnolias are also susceptible to damage if they thaw out too quickly after a frosty night. This can be a problem when a frosted plant catches the morning sun. You can help prevent this by covering exposed shoots with garden fleece. Or, better still, relocate the shrub so that it is not exposed early morning sun and to rapid thawing. In the fruit garden, early blossom of apples, pears, currants and gooseberries are defenceless against late frosts which can destroy an entire crop. The best way to avoid this is to choose a late-flowering variety for a cold spot, such as the apple 'Christmas Pippin' or pear 'Doyenne du Comice'. You can protect wall-trained fruit trees and bushes with garden fleece when a late frost is forecast.
Dealing with frost pockets Dense, cold air sinks to the lowest point in the garden creating a localised cold spot, known as a ‘frost pocket’, that can be several degrees colder than other parts of the garden. If you live on sloping ground, the cold air will flow, like water, down the slope until it reaches the bottom of the slope or is trapped behind a solid barrier, such as a wall, fence or an evergreen hedge, part-way down. You can help prevent cold air collecting in your garden by removing solid barriers or introducing ‘drainage’ holes, through which the cold air can escape. Raising the base of an evergreen hedge slightly by judicious pruning can do the trick, as can removing the gravel board from a fence panel at the lowest point along the boundary. You can also use strategically placed solid barriers to your advantage - positioned along the highest boundaries to prevent the cold air flowing into your garden in the first place.
Wind Very strong gusts of wind can damage all exposed plants. However, some types of trees and shrubs are particularly susceptible. Structural weaknesses, such as brittle branches, weak junctions between branch and trunk as well as over-developed canopies and under-developed root systems, are the most common problems. Small broken and damaged branches can be removed using a pruning saw, loppers or pair of secateurs, with pole-handled versions available that can be operated from the safety of the ground. Larger branches may require a chainsaw. If you are at all worried about a mature tree, seek professional advice either from a qualified tree surgeon or contact the tree officer at your local authority for help and advice. Young, uprooted trees can often be saved by propping them up vertically or replanting and staking firmly.
Some vigorous shrubs, such as roses and buddleja, produce long, whippy shoots that act like a sail in the wind - rocking the plant back and forth, loosening the roots. All affected shrubs should be firmed in and can be staked or cut back to avoid further problems. Conifers and other evergreens are more prone to scorch as a result of windy weather in sub-zero temperatures. This is because they continue to lose moisture from the foliage when their roots are unable to take up sufficient water from the frozen ground. The wind simply magnifies the dehydration effect, usually most apparent on the windward side of the evergreen. Protect unaffected plants using windbreak material and leave trimming burnt foliage until new growth starts in the spring.
In mid to late spring the creeping blueblossom and Siberian flag will do all the work providing a soft mixture of blues. They then make way for the delicious deep crimson flowers of the Scots heather which takes over where they left off, and carries on flowering right into the autumn.
Rain Most garden plants can cope with normal winter rains. However, a few are susceptible, notably many alpines and hairy-leaved plants, which are liable to rot if their crown or foliage remains wet for long periods. Since the wettest conditions can often occur this month (even though January and February will take some beating!), it is still worth protecting prized plants with open-ended cloches or a horizontal pane of glass, held above the vulnerable plant on stacks of bricks.
If the soil becomes waterlogged or flooded for any length of time, most plants will suffer. Often the first signs are noticed later in the spring or even early summer. Typical symptoms include yellowing leaves and wilting new growth that is often mistaken for drought. Many herbaceous plants simply rot away, never to be seen again. On soil that regularly remains wet for long periods, you can help improve rooting conditions, to some extent, by incorporating well-rotted, organic matter and grit before planting, or planting on ridges, mounds and in raised beds. However, the only long-term solution is to improve the soil drainage by installing land-drains. But the best solution, in my experience, is to grow bog-loving plants that are well-adapted to growing in wet soil conditions (see also Creating a bog garden).
