Top ten hedges

I love hedges. In almost every beautiful garden I visit, there is at least one immaculately kept wall of foliage and in my mind’s eye, my own garden will one day be full of them. But when it comes to hedges, I seem to be addicted with the gardener’s equivalent of “fear of commitment”. Planting a hedge is easy. Deciding exactly what (and where) to plant is not so easy. It’s not as if we’ll want to change our minds after putting in a hundred plants.

Hedges are permanent, high-impact features. Although not as expensive as fences, they require outlay, unless you have the talent and means to grow your own from cuttings. To this end, I have at least planted a collection of “mother plants”. These “future hedges” yet to materialise include various forms of Buxus, Corokia, Portuguese laurel, Irish yew and Osmanthus. The other aspect of committing to a hedge is maintenance. Just as a lawn needs regular upkeep, if a hedge is to remain an asset rather than an eyesore, it must be trimmed. If there isn’t a keen and able hedge trimmer in residence, it’s worth factoring in some hired help.

Choosing a hedge

The options are wide and varied and there are without doubt many great hedges yet to be discovered. But for best results, it pays to look around at what’s growing successfully in your locality. Here are 10 of the most tried and true of the medium to tall hedges grown in New Zealand gardens today.

Use hedges to...

  • Create shelter for people and plants. A hedge is more effective than a solid barrier, because it is permeable and slows the wind rather than simply deflecting it.
  • Enhance the privacy of your property. Hedges need not be restricted only to property boundaries.
  • Block dust and absorb noise.
  • Create garden rooms, adding excitement and the element of surprise to your garden.
  • Add definition and permanent structure, so your garden looks good all year round, especially in winter.
  • Add colour highlights with flowers (e.g. camellias) or contrasting foliage colour (e.g. corokia, red barberry, photinia).
  • Create an elegant green backdrop for decorative shrubs and perennials.
  • Screen unwanted vistas or disguise an unattractive fence line.
  • Create a haven for birds. Untrimmed hedges are even more effective as wildlife magnets, especially if they have berries (e.g. corokia) or flowers (e.g flax).

Corokia: New Zealand’s corokias rate among the very best hedges, with fine foliage perfect for clipping and a choice of attractive colours. The most versatile is soft olive ‘Genty’s Green’. ‘Frosted Chocolate’ and smaller-leafed ‘Bronze King’ offer attractive green and bronze foliage, which intensifies in winter. ‘Silver Ghost’ has a lacy look with a silver, almost lavender sheen. Ideal for hedges between 30cm and 180cm tall, corokias are frost hardy and coastal tolerant. Well-drained soil is essential.

Pittosporum: Pittosporum ralphii ‘Stephens Island’ makes a superb hedge with lime to olive-green foliage and quick but tightly compact growth up to 3m tall. Keep it as low as 1.5m if you prefer. It is both cold and coastal tolerant. The various forms of Pittosporum tenuifolium (kohuhu) are long-time favourites for screen planting in town gardens, while P. crassifolium (karo) makes an excellent shelter hedge on windy coastal sites. Pittosporums need free-draining soil.

Griselinia: In mild climates, the bright, glossy-leafed native broadleaf (Griselinia littoralis) is one of the most widely planted hedges and deservedly so. The thick, wavy-edged  leaves  densely clothe  a  strong, wind-resistant hedge. This excellent native shrub is ideal for coastal gardens and grows well in sun or shade. It is, however, intolerant of prolonged wet feet. Young growth may be burned by an untimely frost but otherwise it is quite cold hardy. Griselinia makes a dense hedge and can be kept at any height, from 500mm to 2m. The most popular form is ‘Broadway Mint’, a slightly darker green version of the original species. ‘Twilight’ has dark stems (as opposed to yellow) and mid-green leaves.

Olearia: The New Zealand olearias are excellent as quick-growing, medium-to-tall hedges, especially for coastal sites. Olearia lineata has narrow, olive-like leaves and is amazingly quick growing, fine and open at first but quickly thickening to form an excellent wind barrier. It will tolerate poor soils and frost. O. paniculata is a favourite in the South Island but can be prone to root rot in warmer climates. Another good hedge plant is O. traversii.

Golden totara

Golden totara is slow growing but very long lived and doesn’t require as much trimming as other hedges.

Totara: A lovely totara hedge could be seen as New Zealand’s answer to the Irish yew (Taxus baccata). The golden totara, Podocarpus totara ‘Aurea’, has stood the test of time as an excellent low-maintenance hedge. ‘Matapouri Blue’ is a beautiful blue-green form. Keep it below a metre or grow it tall for privacy.

Thuja: Thuja occidentalis  ‘Smaragd’, also known as‘Emerald Green’, is the latest conifer of choice for modern hedges. More compact and easier to maintain than the extremely quick-growing Cupressus ‘Leighton’s Green’, ‘Smaragd’ has beautiful, dense, dark green foliage that holds well, all the way to the ground, and responds well to trimming.

Camellia: Camellias make spectacular hedges with dark green foliage and the bonus of a colourful show of flowers for autumn or winter. The sasanqua cultivars and hybrids are especially good value as hedges in the 1m-3m height range. Single white ‘Setsugekka’is a longstanding favourite with superb, dark green foliage. If you like an absolute smothering of bloom, consider the Paradise range. Varieties with supple willowy branches, such as ‘Bonanza’, can also be trained as an espalier against a wall or fence. Camellias are cold-hardy and thrive in a well-drained, humus-rich soil. Trim them immediately after flowering. My favourite camellia hedges are ‘Bonanza’ (hot pink double), ‘Early Pearly’ (white double), ‘Gay Border’ (pink and white single), ‘Setsugekka’ (white single), Paradise camellias,‘Mine-no-yuki’(white double) and‘Yuletide’(red single, very compact).

Beech: A European beech (Fagus sylvatica) hedge is wonderful for seasonal interest – lush green in spring and summer, golden in autumn, then retaining its coppery leaves through winter, while letting the sunlight filter through. There is also the option of planting copper beech as a dark, contrasting hedge, or a mixture of green and copper beech. Trim to shape in summer with a light tidy-up trim in late summer. Beech needs free-draining soil, and benefits from the addition of lime on acidic soils. A good alternative to beech if your soil is damp, hornbeam (Carpinus betulus). It has attractive, serrated, beech-like leaves, which it holds well into winter when clipped as a hedge. Adaptable to a wider range of soil conditions and in shady or cold situations, a hornbeam hedge will grow more quickly than beech, but it will usually require more frequent trimming.

Portuguese laurel

Portuguese laurel grown as clipped standards in Graeme Burton’s Waikato garden.

Portuguese laurel: Prunus lusitanica is stunning in spring when it sprouts shiny, bright green growth. The mature foliage is very dark green with attractive red stalks. It is hardy and easy to grow in any average soil or climate. The only downside to this popular evergreen is that it is prone to thrips in dry summer weather but it always looks spectacular in spring. Prune in summer and spray if necessary to control thrips.

Holly: Tough, tolerant and easy to grow, holly makes a lovely dark green hedge. You’ll want long sleeves and protective gloves at pruning time but its prickly foliage will help deter unwanted visitors. The lovely Ilex x meserveae ‘Blue Angel’ has very dark foliage with dark purple stems and, if pollinated, red winter berries. It grows slowly to about 2m tall but is easily kept trimmed below a metre. For pollination, plant Ilex ‘Blue Prince’ (the larger male form) nearby.