The blackberry lily (Iris domistica), also called the leopard lily, is a tender perennial native to Eastern Russia, China, and Japan. It is actually a member of the iris family, not the lily family. It has foliage like an iris and grows to a height of eighteen inches, but the flower is very different. It is a showery flower that is orange or yellow with darker, often crimson speckles. It perches on a two to three foot tall stem and is about two inches wide. The blossoms generally live only one day, but the plant keeps producing more of them for several weeks in the summer. After the flower fades, it produces a small, pear shaped capsule with seeds resembling blackberries, hence the common name of blackberry lily. These lilies are hardy to zone four.
Plant blackberry lilies in well drained, fertile soil with lots of organic matter worked in to the soil. The lily will die of rot if the soil does not drain well. The blackberry lily also requires full sun to thrive.
Blackberry lilies are easily grown from seed. Sow in potting soil six to eight weeks before the last frost. Cover the tray with plastic wrap and set in a warm place. Keep the seedbed evenly moist and the seeds will germinate in one to two weeks. When the seedlings emerge from the soil, remove the plastic wrap. Transplant the seedlings into peat pots and wait until all danger of frost is past. Then you can plant the seedlings and pot and not disturb the roots. Remember to water in the new plants well.
You can also propagate the lilies by division in the spring or fall. Dig up the rhizome, being careful not to damage it, then cut the lilies apart with a sharp knife. Make sure that each rhizome has two or more leaves on it. Replant the newly separated lilies about a foot apart and at least an inch deep.
Blackberry lilies freely self-seed, so if you do not want them to spread, you must deadhead the spent blooms. It is so efficient at self-seeding that it is considered invasive in some states.
Blackberry lilies should be watered once a week with an inch of water during the growing season. They require less water in the winter. In cold climates, they should be covered in mulch in the winter to protect the rhizome from freezing.
Though generally free from pests and diseases, Iris borers may attack the rhizome. Removing dead or dying leaves will help control these pests. If necessary, two chemicals will kill the borers. The first is acephate and the second is spinosad. You have to time the spray to when the eggs are hatching. You will need to repeat the treatment in ten to fourteen days.
The blackberry lily is poisonous if ingested and should be kept out of the reach of children and pets. Children are especially attracted to the fruit, thinking it is a blackberry.