Deep purple, damson, chocolate, plum, aubergine, pewter . . . successfully incorporating the deepest colours in the plant palette is challenging, but the intensely saturated shades of these near-black beauties are so alluring. In recent years our choice has widened as more breeders turn to the dark side.
Dark colours like this are best viewed at close quarters. At a distance they can look like black holes, while in shade they are lost completely. A garden becomes sullen not sophisticated if too many dark tones are used.
Used sparingly, however, such colours create intensity, mystery and opulence. Ophiopogon planiscapus (lilyturf) has perhaps the truest black foliage. Its matt black, straplike leaves look so otherworldly that they are often used in minimalist schemes, accompanied by plenty of silver. The black of other plants tends towards red or blue: oxblood, ruby, plum, burgundy or wine; and violet, ink, and damson.
Warm red-black flowers such as chocolate cosmos (Cosmos atrosanguineus Chocamocha) and Tulipa ‘Black Parrot’ are wonderful at bringing out the complexity of the darkest tones and so are relatively easy to place in a planting. Flowers that are blue-black are harder to place and may need to be planted next to a mid-tone shade that will offset the severity of the hue. As an example, Iris germanica ‘Black Swan’ would benefit from a partnership with Iris germanica ‘Sable’, linking the extremely dark accent back to more vivacious blues.
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The rich oxblood flowers of Alcea rosea ‘Nigra’ (hollyhock) again create dark but warm lowlights in a scheme. This sultry base can be reinforced with vibrant reds, burnt oranges and maroon. To ensure that your planting works well, include plenty of matt, mid-green foliage. Reinforce these rich colours with more dark foliage but do so sparingly. Fagus sylvatica Atropurpurea (copper beech) makes an excellent backdrop when used as a hedge or tree, its dark purple leaves becoming a warmer, more intense copper-red in the autumn. Physocarpus opulifolius ‘Diabolo’ is also worthy of consideration, with devilishly dark chocolate-purple leaves relieved by white summer flowers. On a smaller scale, for the front of the border, heuchera, Ajuga or Ophiopogon make a fine contribution.
If paring back your plummy foliage choices is a challenge, then the self-seeding annual Atriplex hortensis var. rubra (red orache) will become your secret weapon, threading itself through the planting with more restraint and sophistication than any gardener could ever manage. Anthriscus sylvestris ‘Ravenswing’ is a biennial that serves a similar role, providing useful volume and tonal depth to a juvenile border. The spidery stems of this purple cow parsley are so spacious that they offset the crushing gloom of its deep-wine stems. The white umbels of flowers, which appear in May and June, provide welcome relief in a dusky planting, and even the metallic pewter-purple of the emerging fernlike foliage has its merits.
A thread of darker-toned foliage like this will hold together a design, but so can the saturated blooms of a climber. Clematis ‘Romantika’ displays deep-purple, almost black blooms from July to September. This clematis needs a light backdrop or a spot at the front of the border if the blooms are not to get lost. A yellow-leaved shrub would be ideal, the golden foliage acting as a bridge back to the fluttering, pale yellow stamens in the centre of these velvety blooms. Clematis ‘Niobe’ produces oxblood flowers that appear almost black upon opening. The warm tones in this richly coloured clematis add just the right amount of moodiness to a planting that leans into the dark side. Clematis viticella ‘Black Prince’, which flowers from July to September, does not have these pale-coloured stamens to lift the sinister colouring, and is to my mind much harder to use successfully. It does, however, look rather sumptuous when grown on its own in a freestanding pot, so that the dark flowers can be appreciated up close. A good rule of thumb is to aim for no more than 10 per cent of plummy, dark shades. Any more than this will usually become too gloomy.
If you are gardening on a smaller scale, in a courtyard for example, you can use hard landscaping material to relieve the saturated tones. Use neutral pale or dove greys for stone and pots, and a silver-grey stain for fencing. Add depth of tone with matt charcoal or slate grey which will make the reds and blues in your “black” plants seem even more vivid.
Dark colours are simplest to get right when used to intensify a foundation of neutral green foliage, or dispersed through a border as an opulent accent. If you are interested in adding some lower register notes, you could start this spring by sowing cosmos, cornflower and scabious — annual flower seeds — either under cover now or directly into the beds from next month. You might also want to thread some burgundy bands of foliage through the beds, perhaps by direct-sowing red orache in any gaps. Adding an intensely dark clematis is another way to experiment with this colour scheme, which, if planted now, will be romping away by the time it comes to flower in July.
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Deep purples
Ophiopogon planiscapus ‘Nigrescens’ (lilyturf)
This slow-growing perennial produces low mounds of matt black, strappy leaves up to 20cm long. Although grown mainly for the unusual foliage, lilyturf produces tiny bells of pink-white summer flowers. These are followed in early autumn by pewter berries, which mature to a shiny black. Plant in full sun for the best foliage and berry colour. Reaching a mature height of only 25cm, this dwarf plant works best in a pot or at the front of a border. It is very slow growing but an excellent foil plant for gravel plantings where it will provide neat, year-round interes
Ajuga reptans Black Scallop (bugle)
Glossy, dark-pewter foliage with scalloped edges makes this spreading groundcover as decorative as it is useful. As such, it is rarely confined to the moist shady spots, where it is happiest, and can often be found in windowboxes, mixed containers and at the front of herbaceous borders, where it does well so long as the soil doesn’t become too dry. The large leaves of this near-black edging plant produce their darkest colouring in full sun. In shadier spots, the foliage assumes more of a rich burgundy hue. Sun or shade, this bugle will produce small blue flower spikes from April to June.
Heuchera ‘Obsidian’ (coral bells)
The glossy maroon leaves of this compact heuchera darken over the season becoming an opaque jet-black, with the glassy sheen of its namesake. In May and June, creamy-white spires of flowers stand up to 50cm tall, held above the healthy evergreen foliage. These pale flower spikes, which open from smoked-lilac buds, offer an uplifting contrast to the dark leaves. Plant this hardworking heuchera in well-drained soil, in sun or partial shade, in a pot or at the front of a border.
Centaurea cyanus ‘Black Ball’ (cornflower)
The ruffled double petals of this deep-plum cornflower, also known as bachelor’s buttons, make it a popular annual addition to both the vegetable patch and the border. Remarkably, the intensity of the colour doesn’t fade, even in bright sunlight. This 90cm tall cornflower can be sown directly into the soil between March and April, in well drained soil that has been raked to a fine tilth. Sow in drills at 30cm spacing, then thin out once the seedlings are large enough to handle. If sown now, flowers will start to bloom in June and should continue until early September. This decorative flower will attract bees and butterflies.
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Scabiosa atropurpurea ‘Ace of Spades’
These deep damson scabious are useful for cutting or border interest. Velvety pin cushion flowers stand 100cm tall on thin wiry stems and flower reliably for four to five months. This excellent annual is easily grown from seed and can be grown in pots or used as a filler in borders. Sow now into root trainers or modules, or direct-sow into a sunny spot from April. You should start seeing flowers in as little as four weeks, and if you pick them regularly, this moody scabious will go on producing throughout the summer.
Tulipa ‘Queen of the Night’
This famously dark, single late tulip flowers throughout May. It stands 60cm tall on sturdy stems with distinctive cup-shaped blooms that can appear to be anything from maroon to black depending on the light. These large, sultry blooms are reliable too, returning strongly each year. Plant 20cm deep and at least 5cm apart in well-drained soil. To further enhance the drama of this remarkable colouring, partner with a pale tulip such as T ‘Maureen’ or the lily flowered T ‘White Triumphator’. Plant out pot-grown specimens in spring or plant the dry bulbs from September to December.
Actaea simplex ‘Brunette’ (bugbane)
Bugbane’s dark fern-like foliage is particularly fine: dark chocolate burgundy and finely cut. It creates a strong architectural detailing especially when planted on a grand scale. Creamy bottlebrush flowers appear from July to August, adding a further 60cm to the already imposing 120cm height. The flowers are as fragrant as they are stately, making this a fine form for both the woodland and cottage garden. An excellent plant for late-season interest. Plant in damp shade, in soil enriched with plenty of leaf mould.
Sambucus ‘Black Lace’ (black elder)
This ornamental elder has finely cut foliage in the darkest blue-black hue. Luckily it retains plenty of the strong genetics of our common native and remains surprisingly hardy and easy to grow. Happiest in full sun, it will thrive in a wide range of soils, (even waterlogged or chalky soil) reaching a height of more than 3m if allowed to romp away. Most gardeners choose to grow this specimen as a coppiced form, cutting it right back to the ground in early spring. This drastic pruning not only contains its size but results in larger leaves. Pale pink composite flowers, 15cm wide, complement the dark leaves in May and June and are followed in late summer by familiar elderberries.
Clematis ‘Romantika’
The large flowers of this late clematis open black before settling to a vuluptuous deep violet. This outstanding clematis will happily scramble 200cm up an obelisk in a pot, or into an established rose or shrub. Each velvety flower can reach 14cm across and is lit up in the centre by delicate pale-yellow anthers. Like many of its relatives, this fully hardy climber performs best on new growth and should be pruned hard to a pair of strong buds, about 15cm above the ground, in February or early March. Feed after pruning with a slow-release balanced fertiliser and mulch around the crown.
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Phormium tenax ‘Purpureum’ (New Zealand flax)
This bold architectural plant makes a large clump of sword-shaped leaves 2m tall. These huge leaves are purple, flushed green, and have an attractive glaucous finish. This resilient giant is drought-tolerant and makes a low-maintenance choice for pots and planters. It can also make a fine addition to a “hot” border where its tropical appearance can be put to good effect. Phormium, although hardy, can be damaged by cold winds and severe frosts, so plant it in a large pot or in a sheltered courtyard and be prepared to offer it some winter protection.