How to Grow Lisianthus from Seed
Most people consider the gorgeous rose-like flowers of lisianthus to be an exotic (and expensive) florist flower, or sometimes as an exotic and expensive bedding plant.
Lisianthus—called “Lizzies” by nurserymen and other aficionados—produce numerous large (about 2”-3”) rose-like flowers in deep blue, white, pink, or red on a plant with light green succulent foliage. The plant grows from one to three feet in height.
Lizzies are a favorite florist flower for bridal bouquets. I first saw them used as a bedding plant about twenty years ago at a church in Prairie Village, Kansas, where the double blue, rose-like flowers had been planted in a bed in front of a statue of the Blessed Virgin—someone having judged that these “blue roses” would be a fitting tribute.
In their wild form, Lizzies are entirely native to the United States, under the scientific names Eustoma exaltatum, Eustoma exaltatum ssp. Russellianum, and Eustoma exaltatum ssp. exaltatum—more than you wanted to know, I suspect—and they are known by the common names Texas Bluebell and Prairie Gentian. (Other common names include: Blue Marsh Lily, Bluebell Gentian, Catchfly Prairie Gentian, Small Bluebell, and Western Blue Gentian.)
These are some of the most glamorous of our native wildflowers and, perhaps because of their nearly irresistible beauty, they have been harvested to near extinction within their range, which is along the southern coastal regions from Florida through Texas to California, and up the West Coast.
These lovely Texas Bluebells, or Prairie Gentians, were not scorned when they came to the attention of plant breeders in Europe and Asia. The present-day Lizzies represent 70 years of work by Japanese breeders, which has produced a wide range of colors and large double flowers.
LISIANTHUS SEED-SOWING REQUIREMENTS: Patience, Surface Sowing, Continually Moist Sowing Medium, Light, and More Patience
Lisianthus was first introduced in the US in the early 1980s, although they didn’t come to my personal attention until the late 1980s. I was able to grow them from seed to bloom with a high level of success on the first try.
This is because Lizzies—which are sometimes claimed to be difficult for the amateur to grow from seed—are actually easy from seed, and the germination rate is excellent! Every seed you sow should eventually produce a sturdy plant with many glorious blooms.
WHEN TO START SEEDS INDOORS
The main requirement for growing lisianthus successfully from seed is patience. Lots of patience. Lisianthus requires about a six-month growing period from seed-sowing to flower. In my area, at the northern edge of Zone 6, where we have a six-month growing season and an average last frost date of April 15th, seeds should be sown indoors, preferably under plant lights about the beginning of January, or even as early as mid-December.
Germination takes two to three weeks at temperatures of 70° to 75°. Seedlings require light to germinate, so they will need to go in a sunny window or be placed under plant lights.
LIZZIE SEEDS NEED LIGHT TO GERMINATE; DO NOT COVER SEED
As with all seeds that require light to germinate, the seeds must not be covered. This is especially important for Lizzies, because the seeds are very tiny and sowing is simply a matter of lightly pressing the seeds into damp soil medium. Follow this same procedure, even if using pelleted seeds.
The way to sow Lizzies is to put pre-moistened growing medium into the container of your choice and then gently press the seeds into the surface of the damp medium.
Seeds must be kept moist until germination, preferably without surface watering, which might disturb the seeds and bury them under the sowing medium. I have suggested peat pots or cells, because they allow for easy bottom-watering, which is critical to avoid disturbing the surface-sown seeds. The easiest way to keep seeds and sowing medium continually moist is to cover the containers with plastic bags.
I used packages of peat planting cells, filled them with moist seed-starting medium, pressed the seeds into the surface of each cell, bottom-watered the peat cells by setting them in a shallow pan of water, and tucked the 8-celled peat containers into plastic bags.
It’s a good idea to bottom-water peat cells and peat pots after sowing seeds, because the dry peat may suck all the moisture out of the planting medium.
KEEP MOIST; BOTTOM-WATER TO AVOID DISTURBING THE SEEDS
Peat cell packs or peat pots work well because they are easily bottom-watered. If the sowing medium begins starts to dry out—which is a distinct possibility over 14-21 days—just set the peat cell pack or peat pots in a shallow pan of water and allow them to absorb moisture from the bottom. Once the medium is moist again, return the containers to their plastic bags.
When people remark that Lizzie seedlings are very slow-growing, they are not kidding. Seedlings are likely to reach only about ½” in height two months after germinating.
As with most seedlings that are started indoors, Lizzies benefit from transplanting to individual containers a month or so before transplanting outdoors. They should be transplanted to individual containers when the seedlings have developed their second set of true leaves.
Transplant Lizzies outdoors to the flowerbed after all danger of frost has passed. Harden them off before transplanting outdoors by moving them outdoors for gradually increasing periods of time over a period of about three days.
If planted outdoors in April, you will probably have your first blooms in June.
Can Lizzies Be Over-Wintered Indoors and Re-Planted Outdoors Next Spring?
As you know, you went to one heck of a lot of trouble raising these beauties from seed. It would be nice not to have to repeat the entire process every year.
Lizzies are actually a tender perennial—meaning that they would be perennial in a frost-free climate—so by all means pot them up and bring them indoors to over-winter in a sunny location until they can be planted back outdoors next spring.
Lizzies that are brought indoors before the first frost not only thrive, but are likely to continue to bloom indoors until Thanksgiving! Is that a treat, or what?
When flowering stems are spent, it is best to cut them back, so that each pot contains only the basal rosette of leaves. Treat them as you would most other houseplants, giving water only after the potting medium has dried out.
How many years will Lizzies live, if over-wintered indoors? Plants and flowers, like all other creatures, have a life-span that is typical of their particular species. We know, for example, that dogs don’t live as long as humans, and giant sequoias live a lot longer than elms and cottonwoods.
Perennial flowers likewise have variable life-expectancies, and some perennial flowers are often described as annuals because they are short-lived perennials, or because they are best treated as annuals, or because not all varieties of the species are reliably perennial.
What we have with Lizzies is a perennial flower whose development into gorgeous varieties is fairly recent. People are only beginning to recognize that it is feasible to over-winter them indoors. I suspect that their expected life-span varies depending on variety, and is actually unknown.
So, when it comes to over-wintering Lizzies indoors over a period of several years, I doubt if there is a definite answer to that question at this time, especially for a specific cultivar. As Erma Bombeck put it, “You are on our own, Bernice.”