Dark leaves do most of the work and near black flowers finish the job. Your witchy garden plants fall into two groups. Deep purple foliage carries the mass, and a handful of sooty blooms work as accents on top of it. Then you want one white night bloomer so the bed still shows up after the sun goes down. Most goth garden plants are grown for leaves, not petals. That is why the look holds from spring to frost instead of two weeks in June.
The smell reaches me before I see anything. The moonflower I planted on the fence opens wide and white around nine at night, and the whole step goes sweet enough to stop me mid stride. Hummingbird moths work it in the dark, hovering like tiny birds you hear more than see. The coleus in the pots by my back door reads flat black at that hour. By dawn the flower has shut again and there is nothing on the vine but green.
Sort your witchy garden plants by job. Your foliage is the block of color that sits there all season and holds the shape of your planting. Near black flowers are accents and you want them in small numbers, because a whole drift of them turns into a dark hole in the bed. Light changes what you get, too. A purple black leaf reads closest to true black in soft light or shade, and hard afternoon sun pulls the purple and bronze back to the surface, so site your darkest plants for the hour you actually walk past them.
UF/IFAS Extension put together a list of these for Florida conditions, and you can use it as a starting point anywhere with a warm summer. Coleus is the backbone of any group of dark foliage plants. You get 3 feet (0.9 m) tall and wide, and ColorBlaze Wicked Witch and ColorBlaze Dark Star are the dark ones to look for. Ornamental sweet potato spills rather than stands, so give it the edge of your bed. Sweet Caroline Bewitched After Midnight and Illusion Midnight Lace both run deep purple to black, and you grow them for the leaves, since the tubers are not for eating.
For flowers, black petunias carry the accent work in pots and along your front edge. The three to look for are Black Cat, Phantom and Pinstripe, and all of them read as velvety dark purple rather than true black. Rayless sunflower is the strange one, and the one I would put in first. You get a Florida native perennial to 3 feet (0.9 m), deep purple to brown, with no ray petals at all, so what you see is the dark center and nothing around it. Your plants bloom through summer and fall.
Blood lily earns a spot of its own. Your plant tops out at 2 feet (0.6 m) and pushes up a globe shaped head that can reach 10 inches (25 cm) across, which is a lot of flower on a short stem. The bulb divides, so the one you buy this year turns into several later on.
Plant your witchy garden plants in that order and the bed comes together. Foliage first, because you need it to look right in July when nothing is in bloom. Then your sooty flowers, in a clump instead of scattered around. Save the moonflower for last and put it on a fence or a post you walk past after dark. One white bloomer against all that purple does more for the effect than another black plant ever will.
Read the full article: 10 Black Flowers That Are Not Truly Black
