Roses are red, violets are blue, lisianthus is red, blue, purple, pink, orange, yellow, and even lime green shades, too! Pardon my poetry, but the wide array of colors lisianthus plants come in deserves some appreciation. What other flower looks like a rose but can naturally be lime green?
Lisianthus plants are often used in floral arrangements due to its resemblance to a rose and its longevity. They have a long vase life and can last up to two weeks when they’re cut and put into water, and maybe a little longer if you give them flower food. Roses only last about a week, making lisianthus a bit more of a cost-effective yet elegant cut flower option.
Lisianthus plants are more than just something pretty to look at; they’re a great pollinator for the garden! Bees, butterflies, and hummingbirds will likely flock to your lisianthus plants all summer long. They’re a great addition to your garden if you need help attracting pollinators and enjoy cut flowers. Cutting them will encourage new growth, so you can keep them around inside and outside all throughout their growing season.
Let’s dig into why you should grow lisianthus plants in your garden!
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Quick Care Guide
| Common Name | Lisianthus, prairie gentian, bluebell gentian |
| Scientific Name | Eustoma grandiflorum |
| Family | Gentians (Gentianaceae) |
| Height & Spread | Height: 1-3 feet (30-91 centimeters), Spread: 9-12 inches (22-30 centimeters) |
| Light | Full sun in the morning, part shade in the afternoon |
| Soil | Loamy, sandy, well-drained soil |
| Water | Allow to dry between waterings |
| Pests & Diseases | Aphids, thrips, whiteflies, fungal diseases, viruses |
All About Lisianthus
Lisianthus plants, or Eustoma grandiflorum, are flowering plants native to northern Mexico and the Great Plains in the United States. Despite being native to this area, it didn’t really become popular in the United States until the 1980s. When it first appeared in seed catalogs, it was called Lisianthus russellianus. When it was later recognized as part of the Eustoma genus, people were used to calling it lisianthus, so the name stuck around. It’s also called prairie gentian or bluebell gentian since it’s in the gentian family.
Lisianthus flowers are often planted in gardens to add a fresh and elegant feeling and attract pollinators. They come in a large range of colors, so you’ll likely see various pollinators show up in your garden. They’re herbaceous, with dark green flower stalks reaching up to 3 feet tall, so they’re best suited for growing in the ground or in raised beds in most situations. However, there are dwarf varieties that won’t grow more than 1 foot tall that will work well as potted plants on patios.
Most lisianthus plants are typically grown as an annual, but in USDA hardiness zones 8-10, they’re biennial, or blooming sized plants, meaning they don’t flower in the first year but they will in the second year, and then they’ll die. In USDA zone 10, you’ll most likely get to grow it as a perennial that comes back each year.
To grow lisianthus flowers, you’ll need to plant seeds in the winter, likely around January. If you’re in the ideal growing zones, you should be able to try direct sowing germination outdoors and successfully produce plants. Otherwise, you’ll need to plant them inside with grow lights and transplant them into the ground in the spring. You’ll see your plants bloom in early summer, and you can keep the flower power going through fall until the first frost. In warmer climates, you may be able to plant seed in the late summer and overwinter the plant so that it blooms in the late spring or early summer.
The seed can be a little tricky to plant, however. They’re extremely tiny, and some cultivars are known to take quite a while to germinate. Your best bet may be to start these plants indoors well in advance of when you’d expect to need to start them, just to ensure you have them when it’s time for them to be planted out.
Care
Lisianthus has a bit of a reputation of being difficult to grow. It may seem that way to beginners, but once you know how to care for them, putting it into practice is easy. Be patient when growing lisianthus seed since they take a very long time to show signs of life. They can take up to three weeks to germinate and six months before you see the first flower.
Light & Temperature
Lisianthus is an elegant yet heat-loving plant native to USDA zones 8-10, but it doesn’t like direct afternoon sun. When you plant lisianthus, pick a planting site where it will receive full sun in the morning with part shade in the afternoon when the sun is the most brutal. In climates with mild summers such as the Pacific Northwest, you may not need as much shade in the afternoon and they may be able to tolerate full sun or bright light conditions. If you start seeds indoors, a grow light will be necessary to produce healthy seedling growth since a window provides limited sun, and they’ll need something that mimics the brightness of full sun for at least part of the day.
The lowest temperature lisianthus can survive outdoors is 10°F (-12°C). If you live in zones colder than 8, you’ll need to bring your plants inside until the temperatures warm up again. In zone 7, you may be able to save it with a thick layer of mulch and row covers until the following spring, but keep in mind that it needs to receive plenty of light.
Water & Humidity
Lisianthus prefers to have an even amount of water, about 1 inch per week. If it doesn’t rain often, the plant will need to be watered. Young seedlings should be kept moist until they’re mature, but even in maturity, the flowers perform best when they receive plenty of water.
Water lisianthus at the base and make sure the water doesn’t touch the leaves. Soaker hoses will be the easiest way to accomplish this in raised beds and the ground. Lisianthus is drought tolerant, so if you miss a watering or two, your flowers should be fine.
Be careful not to overwater since that can increase the chances of your flowers contracting plant diseases. Watering early in the morning is ideal so the water can have time to soak into the ground before the sun evaporates any excess moisture. It will also give the soil time to dry out a bit before nighttime, which will reduce diseases. Lisianthus needs well-drained soil so the water can easily run off and not puddle around the roots.
Mature lisianthus will need less water in spring and fall when the temperatures aren’t so hot. Something to keep in mind is that in their native habitat, lisianthus enjoys a hot summer with dry spells that involve just a a few drops of rain, so if they’re grown in damp climates, they’ll need less watering and may even suffer from too much water. As hot summers fade during the late summer months, you can gradually decrease the watering needs.
Soil
Lisianthus needs well-draining soil to prevent water from pooling up around the roots. A loamy and sandy mixture that’s rich in nutrients is ideal. Adding compost or fertilizer to in-ground or potted plants will help them grow more foliage, and the flowers bloom.
The pH range for lisianthus flowers is slightly alkaline soil at 6.2-6.8. It won’t grow well in acidic soil, so avoid letting the acidity dip below 6.2. The ideal soil temperature range to grow lisianthus is 59-73.4°F (15-23°C). They can survive a little cooler or warmer, but this is the range you should aim for to make sure your lisianthus is happy. If you have cold winters, feel free to grow them as potted plants and bring them in when it gets too cold for them.
Fertilizer
One of the joys of growing lisianthus is that it has very few fertilizer needs unless you want it to flower heavily. You can plant it with rich compost in the beginning and refresh the soil with more compost once or twice a year.
Applying a fertilizer that’s high in potassium throughout the growing season will increase the number of gorgeous flowers you have on each lisianthus plant. Using a fertilizer that’s high in nitrogen will make the plants favor foliage instead of flowers.
Propagation
Lisianthus plants are self-seeding, so you can allow nature to take its course at filling your flower beds. The plants don’t like to have their roots disturbed, but if you want to move a plant from one location to another, you can gently dig up seedlings and plant them where you want them.
You can save lisianthus seed after the blooms have died and sprinkle them over the soil. The seed needs sunlight to germinate, so press them gently into the soil but don’t allow them to get covered up. Try to avoid planting them in unprotected open areas since the wind may blow away the superfine seed. Even greenhouse growers may have a lot of luck with lisianthus in this regard.
Pruning
Lisianthus make great cut flowers in flower arrangement situations and bouquets, so pruning is likely something you’ll do often if you want beautiful flowers in your home. Once the rose-like flowers bloom, cut them at the bottom of the stem. Lisianthus plants can grow several tall stems that branch out and form more stems, so only cut the ones you need. Remove the leaves and place them in water in a vase.
Pruning lisianthus will encourage the plants to grow new blooms, so you can cut flower stems all season long to keep your flowers growing until the first frost. If you allow the flowers to stay on the plant, remove spent flowers to encourage new growth. To deadhead the old blooms, look below the spent flower for a point where a pair of leaves is located, and cut off just above that to encourage further growth.
Troubleshooting
When it comes to pests and diseases, lisianthus doesn’t cause much of a fuss. Most issues are commonly caused by accidental overwatering or allowing the leaves to get wet.
Pests
Lisianthus is susceptible to hungry insects looking for plant sap to eat. Aphids, whiteflies, and thrips may not kill the entire plant, but they will cause damage that will take away from the beauty of the blooms and foliage. Repeated applications of neem oil or insecticidal soap will kill them.
Diseases
Lisianthus can get fungal diseases such as botrytis cinerea and downy mildew. Botrytis is a grey mold that can form on blooms, light green buds, foliage, and stems. Downy mildew is a grey patch that begins on the underside of leaves but can eventually cover both sides. These diseases can be avoided by never watering the leaves and never overcrowding the plants so they can have good airflow. Treatment with neem oil or a copper-based fungicide may help treat both.
Viruses can be caused by pests and spread from plant to plant. They usually cause mottled and spotted leaves. It can be prevented by providing good airflow between plants and controlling pests as soon as you see them. You’ll have to remove and throw away infected plants since there’s no way to treat most plant viruses.
Frequently Asked Questions
Q: Are lisianthus hard to grow?
A: Lisianthus is considered hard to grow because the seeds take a long time to germinate, and it can take up to six months before you see them flower. But, if you have the patience and can provide the plants with part shade and enough water, you’ll find that they’re not so difficult to care for, and they make a beautiful addition to any flower garden.
Q: Do lisianthus come back every year?
A: Lisianthus will come back in warm climates. In USDA zones 8 and 9, the lisianthus grows as a biennial, so it will last for two years. In zone 10, it’s grown as a perennial that will come back each year. In colder areas, you can grow lisianthus as an annual.
Q: Is lisianthus poisonous to humans?
A: Lisianthus isn’t poisonous to humans, so they’re safe to plant in containers on patios and to bring indoors as cut flower arrangements.
Q: Does lisianthus like sun or shade?
A: These are full sun plants, but they don’t like scorching afternoon sun. Aim for at least 8 hours of light a day, and provide some shade in the hottest part of the day.
