A formal garden design is built around balance, symmetry, straight lines and geometric shapes. There are certainly some plants that fit this style, but it can be more a matter of how you use them
Clipped hedges provide structure, especially if evergreen. They act as boundaries for borders. They also introduce the possibility of architectural topiary. Box is the classic option, but currently box blight disease and the spread of box tree caterpillar may encourage gardeners into making more innovative choices.
- Grow them: Box is happy in sun or semi-shade.
- Combine with: a modern trend is to make double or triple tiers of hedging in straight lines or curves. Box compartments are often infilled by herbaceous ground cover, roses or bedding.
- Best for a formal garden: Buxus sempervirens is the standard choice. B. 'Suffruticosa' is the dwarf variety. Other choices for formal hedging are: yew, Taxus baccata AGM, beech Fagus sylvatica AGM and holly, Ilex aquifolium AGM.
Indicative of order, pleached trees play on the historic theme of man ruling over nature. They provide height, but allow views beneath. Small leaved lime, Tilia cordata, is the usual choice.
Viburnums lend themselves to a formal setting. Evergreen types can provide underplanting or hedges while some white-flowered deciduous cultivars offer structural form or timeless romanticism.
- Grow them: viburnums thrive in many soil types in full sun and partial shade.
- Combine with: in a shrub border, try plants with a later season interest like shrub roses, abelias or skimmias.
- Best for a formal garden: A viburnum with horizontal planes, V. plicatum f. tomentosum 'Mariesii' AGM; Viburnum davidii AGM, a dark evergreen with white flowers and metallic blue berries; the bridal, early summer flowering Viburnum opulus ‘Roseum' AGM.
A limited colour palette is usually better for formal gardens, especially whites, silvers and pastels. Agapanthus can be grown in long ribbons through borders or in blocks. They also suit repeated containers.
- Grow them: Agapanthus prefer fertile, moist but well-drained soil in full sun.
- Combine with: Herbaceous companions include lamb's ear, silver-leaved artemisias and peonies.
- Best for a formal garden: Many to choose from, but: Agapanthus ‘Loch Hope’ AGM, a deep blue flowered cultivar; ‘Bressingham White’, a striking white selection.
Hydrangeas provide sterling additions to the formal garden in borders or pots, providing bountiful volume and long-lasting summer colour.
More from the RHS
Garden design resources
Formal garden design gallery