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Trees and shrubs

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Planting and moving

Continue to plant deciduous hedging plants, shrubs, trees and climbers. Stakes and rabbit guards should be put in place at the time of planting trees, to prevent damage to the rootball or bark.

This is the best month for planting roses in heavy soils or in cold areas. Avoid planting in areas where roses were previously grown, otherwise new introductions may suffer from replant disease.

Towards the end of the month, you can plant evergreen shrubs and trees left unplanted since the autumn.

In warmer areas, evergreen trees and shrubs can be moved in late March. It is better to wait until early April in colder areas. Make sure the soil is not waterlogged or frozen solid, and bear in mind that they will need careful attention to watering if they are to survive their first summer after moving.

If you are hesitant to move large trees and shrubs so close to the summer, then you can prepare mature specimens for moving next autumn. Digging a narrow trench around the plant, cutting some of the roots in the process, encourages the growth of finer, fibrous roots, rather than the thick tap roots which are harder to remove successfully, and which absorb water less efficiently.

Feeding

Feed trees, shrubs and hedges with a balanced fertiliser (such as Growmore or blood, fish and bone), sprinkling it over the root area before hoeing into the soil surface. This will particularly benefit young, weak, damaged or heavily pruned plants.

Roses will benefit from feeding with a granular rose fertiliser as they come into growth.

Pruning and training

Prune established bush and standard roses as they start growing but before any leaves unfurl.

Many summer or late-summer flowering deciduous shrubs can be pruned between January and March. Examples include Buddleja davidii, Caryopteris clandonensis, Ceratostigma, Hydrangea paniculata, Leycesteria, Lavatera, Perovskia, hardy fuchsia, and deciduous Ceanothus species.

Shrubs such as Buddleja davidii, Salix alba var. vitellina cultivars, Eucalyptus gunnii and Cornus sanguinea cultivars are usually stooled (i.e. cut back very hard), because this keeps them at a manageable size, as well as deepening the stem colour of those species grown for their winter stem colour.

Delay pruning spring-flowering shrubs until after they have flowered, otherwise this year's display will be lost.

Do not prune slightly tender evergreen shrubs (such as Choisya, best left until April), but do tackle hardier examples (such as Prunus laurocerasus, the cherry laurel), if necessary.

Remove any reverted green shoots on hardy variegated evergreens, to prevent reversion taking over.

Deciduous flowering Prunus species (ornamental cherries, plums and almonds) are vulnerable to silver leaf if pruned before mid-summer, and anyway should not require routine pruning if planted with sufficient space for their eventual size.

Maintain pruning on pollarded trees such as willow (Salix) and lime (Tilia), cutting back all growth to within two or three buds of the crown.

Tie wall shrubs and climbers onto their supports to protect them from wind damage.

Spur-prune all current stems on Campsis by cutting back the laterals to within two or three buds of the main branches forming the framework.

Cut back late summer and autumn flowering (group 3) Clematis, if not done last month. Cut to the lowest pair of strong buds above ground level, mulching and feeding afterwards.

Prune winter-flowering jasmine once the flowers have faded. Remove any dead or damaged shoots, tie in new shoots to the main framework, and then shorten all the laterals coming off the main framework to 5cm (2in), cutting to a bud. This will keep the plant neat, and improve flowering next year. It is a good idea to feed and mulch after pruning, as the plant will put on lots of growth in response to cutting back.

Summer-flowering jasmines may also be pruned (if necessary), providing that they are reasonably hardy in their situation. With these you should remove a couple of stems completely to ground level, and avoid cutting back laterals, as this would damage the current year’s flowering potential.

Overgrown climbers can be renovated this month. With deciduous ones, you should now be able to tell which growth is dead and which alive, as the live stems will show buds bursting into life. Suitable climbers include Lonicera (honeysuckle), Hedera (ivy) and rambling roses.

If your trees are too large for you to manage pruning alone, you may need a tree surgeon. Otherwise take care not to damage the tree when sawing off thicker branches.

Propagation

Check hardwood cuttings taken last year. They may need planting or potting on.

Layering is a good way to propagate climbers and lax-stemmed shrubs. Layers should root by next spring, as long as some attention to watering is given during dry weather. Examples to try include Philadelphus, Forsythia, Hydrangea and Lonicera.

General maintenance

Check tree ties and stakes. Replace, tighten or slacken them where necessary.

Firm back newly planted trees and shrubs if they have been lifted by strong winds.

Check protective coverings on newly planted or borderline hardy trees, shrubs and climbers, to ensure they remain secure until the risk of frost has passed.

Remove weeds from around the bases of young trees.

Mulch and feed shrubs, trees, hedges and climbers after pruning, to give them energy for the extra growth they will put on after cutting back.

Trim winter-flowering heathers as the flowers fade. Shears are the ideal tool. This will prevent the plants from becoming leggy and bare.

Sow tree seeds that have been kept in cold storage since collection in the autumn.

Cut out the top rosette of leaves from leggy stems of Mahonia x media cultivars to encourage branching.

Put rabbit guards around newly planted trees and shrubs to protect the bark.

Pest and disease watch

Inspect sick looking box and holly trees for signs of blight.

Bracket fungus on trees is more visible at this time of year. If the tree is in poor health it is worth calling in a tree surgeon for a professional opinion.

Phytophthora root rots can cause die back on mature trees and shrubs. Wet winter weather and poorly drained soils are likely to encourage this problem on susceptible woody plants.

Check for damage or cankers on deciduous trees.

Be aware that pests emerge as the weather gets warmer. Caterpillars, aphids and fly pests may all become problematic during mild spells. Early infestations can often be managed by hand removal, making insecticides unnecessary.

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