Black and very-dark flowers
True black flowers do not exist in nature. What we call "black" in horticulture is the darkest possible expression of deep purple, deep maroon, or deep burgundy -- colors so saturated that they absorb most visible light and appear black in typical viewing conditions. The pigments responsible are.
True black flowers do not exist in nature. What we call "black" in horticulture is the darkest possible expression of deep purple, deep maroon, or deep burgundy — colors so saturated that they absorb most visible light and appear black in typical viewing conditions. The pigments responsible are anthocyanins at very high concentrations, combined in some cases with dark foliage backgrounds.
This guide covers the best plants offering very dark flowers — those marketed and sold as "black" — with honest descriptions of what color they actually are.
The darkest annuals
Black petunia (Petunia × hybrida 'Black Velvet' and 'Black Cat')
Per Missouri Botanical Garden, 'Black Velvet' and 'Black Cat' are the darkest-colored petunias available — deep purple-black with virtually no lighter undertone visible in normal light. They appear genuinely black against light foliage.
- Type: Annual
- Zones: All (as annual)
- Color appearance: Genuine near-black in most conditions
- Use: Containers; borders; high-contrast combinations
Black hollyhock (Alcea rosea 'Nigra' and 'Jet Black')
Per NC State Extension, black hollyhock (A. rosea 'Nigra') produces large dark maroon-purple flowers that appear nearly black in most conditions. One of the oldest dark-flowered cultivars in cultivation, known since the 17th century.
- Type: Biennial (Zone 3–9)
- Height: 5–8 feet
- Bloom: June–August
- Color: Deep maroon-purple; appears black
'Black Adder' agastache (Agastache 'Black Adder')
Per Missouri Botanical Garden, 'Black Adder' produces very dark purple-black flower spikes that are among the darkest in the genus. Highly attractive to bees and hummingbirds.
- Zones: 5–9
- Height: 3 feet
- Bloom: July–September