Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
Blackberry lilies are a garden favorite. Their cheerful flowers light up the garden in the summer and then the dried seed pods with their shiny black seeds provide interest in your garden in the fall and early winter.
What are Blackberry Lilies?
Blackberry lilies are flowering perennials that are native to China, Russia and Japan. They are not lilies. They were originally classified as the sole species of the genus Belamcanda. Modern DNA analysis revealed that they are actually iris, so they were moved to the Iris genus and renamed Iris domestica.
Blackberry lilies are hardy in zones 5 – 10. Like their iris cousins, the plants have sword-like leaves that grow in a fan shape from a rhizome. The rhizome has been used medicinally for centuries to treat throat, liver and spleen ailments as well as malaria, gonorrhea and as an antidote to arrow poison. Modern scientists are testing the rhizome as a treatment for prostate cancer.
The flowers do not look like iris flowers. They are reminiscent of lily flowers. The flowers are borne on a long stalk, usually 2 to 3 feet tall. The stalks are not very sturdy and easily blow over during high winds. You may want to stake them. The flowers themselves have 6 petals. They can be orange or yellow. Both have red spots. The spotted flowers are the origin of its nickname “leopard lily”. Bloom time is summer to early fall. Like daylilies, each flower only lasts a day but each stalk has a succession of flowers on it.
The flowers are followed by large green pods. The pods ripen to a tan color and open revealing the round shiny black seeds inside. They look a bit like blackberries so the plant has come to be called blackberry lily. The seeds remain on the stalks for several months creating winter interest in the garden. The dried stalks and seeds are also used in dried arrangements.
How to Grow Blackberry Lilies
Blackberry lilies prefer full sun but will tolerate a little shade. Plant them in well-drained soil. Soggy soil will cause the rhizome to rot. The plants enjoy regular watering and bloom better when they are watered regularly but they are also drought tolerant in case you forget to water them. There is no need to fertilize your plants. They will get enough nutrients from your garden soil.
Blackberry lilies will readily reseed themselves in your garden if you leave the seeds on the plants. If you do not want them to reseed in your garden, simply prune the flower stalks after they have finished blooming so that the seeds won’t have a chance to form.
In the fall you should remove all of the dead foliage. This will also help prevent rhizome from rotting as well as denying hibernating pests a place to spend the winter.
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How to Divide Blackberry Lilies
Blackberry lilies should be divided regularly to prevent overcrowding which leaves them susceptible to the ravages of iris borers.
Division is similar to iris. In August when the plants have finished flowering, carefully dig up the rhizomes. Using a sharp knife, cut the rhizomes into pieces making sure that each piece has roots and a fan of foliage attached. Discard any dead or diseased pieces. Replant the healthy divisions at least 12 inches apart.
How to Grow Blackberry Lilies From Seed
Blackberry lilies are most often grown from seed, either harvested from the dried seed pods the previous fall or purchased for spring sowing.
You can direct sow the seeds in your garden in the fall (for spring germination) or in the spring. Plant them ¼ inch deep. Fall planted seeds will germinate the following spring after the soil warms. Seeds planted in the spring after the last frost will germinate in 2 to 3 weeks. Seeds for perennial plants take longer to germinate than seeds for annual plants so be patient. After the seedlings have developed their first set of true leaves, thin the seedlings to at least 12 inches apart.
You can also start your seeds indoors 60 days before your last frost date. The seeds will need to be cold stratified to mimic winter weather. Sow your seeds ¼ inch deep in a container of pre-moistened soil, and cover the container with a plastic bag to hold in the moisture. Place the plastic covered container in your refrigerator for 10 – 14 days. Check the soil periodically to make sure that it is still moist. After 2 weeks, remove the plastic covered container from your refrigerator. Remove the plastic bag and place the container on a sunny windowsill. Germination should occur in 2 to 3 weeks. You can plant your seedlings at least 12 inches apart in your garden after your last frost.
© 2019 Caren White
Caren White (author) on January 18, 2020:
Louise, you're going to love them! Don't forget to allow them to go to seed to give you another few months of interest in your garden.
Louise Powles from Norfolk, England on January 18, 2020:
I've never seen this before, but certainly wouldn't mind growing this in my own garden. It's lovely.