The search for plants that appear black is driven by a desire for dramatic and unconventional aesthetics in horticulture. These dark-hued plants offer a striking contrast to the usual greens and bright colors found in nature. True black coloration is rare in the plant kingdom because it would severely limit photosynthetic capacity. The plants we call “black” are instead characterized by extremely high concentrations of pigments, resulting in deep shades of purple, maroon, or dark reddish-brown. This intensely dark appearance provides a unique visual element, adding depth and a sophisticated quality to any garden or landscape design.
The Science of Dark Hues
The dark coloration in these plants is primarily due to the intense accumulation of pigments called anthocyanins. These water-soluble compounds are responsible for producing red, purple, and blue colors in flowers, fruits, and leaves. In “black” plants, the sheer density of these pigments causes nearly all visible light to be absorbed rather than reflected. Maximizing the concentration of anthocyanins effectively masks the green chlorophyll. This high pigment load also acts as a natural sunblock, providing photoprotection against intense light and UV radiation.
Notable Examples in the Garden
The appeal of these dark colors has led to the cultivation of many ornamental varieties that provide a dramatic effect. These striking plants are categorized by the part of the plant that exhibits the dark hue, offering different textural and visual impacts in a design.
Black Flowers
Several popular ornamental flowers have been bred to feature petals that are a velvety, deep black-purple. The ‘Black Velvet’ petunia is famous for its nearly pitch-black, single blooms that absorb light efficiently. Similarly, the ‘Queen of Night’ tulip presents a deep maroon flower that appears black in certain light conditions. Other examples include the ‘Black is Black’ bearded iris and the ‘Nigra’ hollyhock, which both showcase intensely dark flowers.
Black Foliage and Stem
Plants grown primarily for their dark leaves and stems offer season-long color and structure to the garden. One of the darkest foliage plants is Ophiopogon planiscapus ‘Nigrescens,’ commonly known as Black Mondo Grass, which forms clumps of strap-like, nearly black leaves. The ‘Black Magic’ elephant ear (Colocasia esculenta) is prized for its immense, heart-shaped leaves of deep purple-black. Additionally, shrubs like the ‘Diablo’ ninebark (Physocarpus opulifolius) feature dark burgundy-black foliage on arching stems.
Dark Fruits and Vegetables
While the focus is often on ornamental varieties, certain edible plants also exhibit this dark coloration. Some tomatoes, such as the ‘Black Krim’ variety, develop a deep, dusky purple-red skin that appears black when fully ripe. Varieties of hot peppers, like ‘Black Pearl,’ are grown for their small, spherical black fruits and dark purple foliage, providing a dual ornamental and edible purpose. These dark fruits and vegetables also benefit from the anthocyanin content, which acts as an antioxidant.
Cultivating and Using Dark Plants
Maintaining the deepest color in these plants often depends on providing specific light conditions. Many dark-leaved varieties require a significant amount of direct sunlight to encourage the maximum production of anthocyanins. Insufficient light can lead to a less intense color, where the foliage may revert to a duller green or standard purple hue. However, intense afternoon sun can sometimes scorch the delicate leaves, so a location with bright morning sun and afternoon shade is often ideal for foliage plants.
When incorporating these dark hues into a landscape, they are most effective when used for contrast and drama. Because dark colors tend to recede and can disappear into the shadows, placing them against a light-colored background, such as a white wall or silver-leaved plant, makes them stand out. Pairing a black flower or foliage plant with brightly colored companions, like lime green or vivid yellow, is the most effective way to maximize their visual impact. The dark color can also be used to create an illusion of depth, drawing the eye into a planting bed or container arrangement.