RHS Garden Planning Choosing plants for the garden Trees, shrubs and conifers Plants with a firm woody framework – trees, shrubs and conifers – form the backbone of any garden design. Even if not evergreen, they have a permanent presence in the garden and are visible year round (unlike most perennials and all bulbs and annuals). They should be chosen with care – most are long-lived plants and can be difficult to move (if they are in the wrong place) once they are mature. It should also be borne in mind that you may not be able to create the desired effect immediately, as plants have to be allowed to grow. For instance, if you are planting a tree to screen a block of flats outside the garden, it may be several years before the tree does this. Criteria for choosing trees Hardiness Suitability for soil type Rate of growth Ultimate size Impact on the rest of the garden Ornamental features Spring-flowering trees Ornamental cherries Crab apples Hawthorn Rowan Magnolia Amelanchier Laburnum
(Prunus) (Malus) (Crataegus) (Sorbus)
Summer-flowering trees Mount Etna broom Indian bean tree Eucryphia
(Genista aetnensis) (Catalpa bignoniodes)
Autumn fruits Crab apples Hawthorn Rowan
(Malus) (Crataegus) (Sorbus)
Winter-flowering Prunus subhirtella ‘Autumnalis’ Acacia dealbata (sheltered gardens only)
Bark Betula utilis var. jacquemontii Prunus serrula Acer griseum, A. pensylvanicum
Conifers Conifers, mostly evergreen, are heavy plants that give a sense of permanence to a scheme. Note that many ‘dwarf’ conifers are actually slow-growing and
ultimately very large. Blue conifers have their most intense colour after a heavy frost; yellow conifers have their best colour in spring (when the new foliage appears). This should be taken into account when placing them. Hedging Hedges are used in gardens to mark boundaries, provide privacy and security, act as a windbreak (important in a windy, exposed site) and create divisions within a garden. Some hedges are planted more for utility, others for ornamental effect. Some hedging plants can be clipped hard to give a walllike appearance – suitable for formal schemes. Mixed hedges can attract wildlife. Tall hedges Formal evergreen: Yew (Taxus), Leylandii cypress (Cupressocyparis leylandii), western red cedar (Thuja plicata), Portugal laurel (Prunus lusitanica), privet (Ligustrum), holly (Ilex) Formal deciduous: Hornbeam (Carpinus), beech (Fagus) Flowering: Camellia (acid soils only), hawthorn Medium hedges Elaeagnus (evergreen, suitable for coastal gardens), roses (Rosa; flowering, some with autumn fruits), hawthorn (Crataegus; flowering, berrying), Pyracantha (flowering, berrying, thorny), Berberis (flowering, berrying, thorny) Wildlife hedges To attract wildlife a mix of plants is needed to provide: simple, open flowers that attract pollinating insects; berries to feed birds over winter; evergreens to shelter little furry creatures; mainly native plants whose bark will shelter invertebrate life (also a food source for birds) Dog roses Hawthorn Hollies Field maple Wayfarer tree
Rosa canina (flowers and fruits) Crataegus (flowers and fruits) Ilex (evergreen – for berries, plant both male and female plants) Acer campestre (corky bark) Viburnum opulus (flowers and fruits)
Also consider running climbers through the hedge, e.g. ivies (Hedera) to provide a food source for bees in autumn, and Old man’s beard (Clematis vitalba) with fluffy seedheads that provide nesting material for birds. Avoid hazel (Corylus), as this can attract squirrels. Close pruning is not possible. To keep a wildlife hedge neat, trim after flowering, taking care not to remove berrying growth. Dwarf hedges Formal: Box (Buxus), Lonicera nitida Flowering: Lavender (Lavandula), potentilla, rosemary (Rosmarinus), miniature roses (Rosa) Ornamental shrubs Most hardy shrubs are spring-flowering (e.g. forsythia, camellia, most viburnums). Later-flowering shrubs (but not the butterfly bush/Buddleja davidii) – e.g. Hydrangea, fuchsias – tend to be less hardy. These, as well as
others of borderline hardiness such as ceanothus, need to be grown in a sheltered site. Wall shrubs Some shrubs are suitable for training against a wall, either formally or just loosely tied to a support. If the wall is south- or west-facing, this is a good way of growing shrubs of borderline hardiness. Abelia Acacia Callistemon Ceanothus Cestrum Chaenomeles Fremontodendron Itea Pyracantha Solanum
Roses Roses are valued for their long-flowering season, usually summer through early autumn. Use in mixed plantings, with perennials, bulbs and annuals, or en masse as bedding (especially ground cover types). Patio and ground cover roses are also suitable for containers. Climbers can be planted against walls, over pergolas or up trees.