April is the best times of year to plant conifers and evergreen trees and shrubs. As the soil begins to warm up the roots will soon start to grow. The main planting procedure is the same as that described in our February section for bare-rooted subjects.
Plants grown in containers (including deciduous plants now in leaf) can be planted at any time of year, provided that the soil is workable and not waterlogged, frozen, or dry and hard. Prepare the site well by adding plenty of bulky organic matter (well-rotted garden compost or manure) to the soil. Plant firmly and make sure that there is no lack of water during the first, vital, growing season. In windy or exposed areas, protect newly planted shrubs either by staking or surrounding them with windbreak netting.
Although April has a reputation as a rainy month, there are often long, dry periods which, combined with winds, can easily dry-out both evergreen and tender, young deciduous leaves. Therefore keep an eye on the weather and water regularly. Keep a watch on shrubs and climbers planted near walls as these can dry-out very quickly.
To prevent water loss, mulch around trees, shrubs and plants with well-rotted compost, manure or even grass cuttings to help retain soil moisture, as well as keep weeds down and eventually add nutrients to the soil. Providing the soil is damp, the mulch slows down the rate of evaporation from the surface, as well as adding organic matter to the soil, thus further improving its water holding capacity. A good material for mulching around ornamental plants is pulverized bark. It is organic, lasts a long time, does not blow about, and is pleasant to look at.
Frost protection for tender flowers is still necessary in April. Place horticultural fleece over likely victims on cold nights.
Pruning is an ongoing activity towards the end of April, Evergreen and conifer hedges can be clipped now as they start to show signs of growth. April is also the best time to cut hedges back that are becoming top heavy, bare at the base, or too tall. This allows the hedge an entire growing season to recover.
Shrubs that have just finished flowering, such as forsythia, can now be pruned so new flowering shoots will have time to develop for next year.
You can also trim grey-leaved and other dwarf evergreen shrubs, grown mainly for their foliage, such as lavender and cotton lavender (Santolina), once the danger of really cold weather is over. Trimming them back now will encourage fresh, bushy growth from the base, and keep them from becoming leggy and bare.
The butterfly bush (Buddleia) should be pruned back by about two-thirds to encourage strong erect stems.
Prune hardy fuchsias once they come into bud, removing completely any dead branches, weak or crowded wood. Then cut the remaining healthy wood back by about a third.
Keep on the lookout for greenfly around new buds and leaves. You may need to spray with systemic insecticide to ward off attacks.
Roses need a good deal of food and water. Remove hungry weeds which will rapidly use up some of these. From their second year onwards, roses can be mulched to keep moisture in the soil, provide protection from weeds and add extra nutrients. Apply a good 5 cm (2 in) layer of well rotted animal or vegetable manure or compost over the rose bed, but leave a small ring of bare soil around the base of each plant.
April is a good time to propagate shrubs by layering. Rhododendrons, azaleas, magnolias, figs and laurels are good subjects for propagation by layering. In fact any shrub that has branches low enough to touch the ground or supple enough to bend to the ground can be propagated in this fashion.
Layering is a slow process (magnolias may take two years or more to root) however, very little needs to be done after the initial preparation work, and the success rate is good, so it is well worth the wait. For details see our section on Propagation by Layering
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Deciduous trees and shrubs in flower:
Amelanchier (snowy mespilus)
Magnolia (many cultivars)
Malus (crab apple)
Prunus (ornamental cherry)
Ribes (flowering currant)
Spiraea x arguta
Evergreen trees and shrubs in flower:
Osmanthus x burkwoodii
Prunus laurocerasus (Cherry-laurel)
Rosmarinus officinalis (rosemary)