The How to Grow It Project

How to Grow Lisianthus
  • keywords: howtogrow lisianthus, eustoma grandiflorum, prairie gentian, Texas blue bells
  • location: Chicago, Illinois, Zone5

Heidi Hybrid Lisianthus

That's Heidi hybrid lisianthus above. Lisianthus is a half-hardy perennial native to the prairie from Colorado to Nebraska and down to Texas. In the wild it is blue but the well-bred varieties come in blue, lavender, various shades of pink, white, white with a purple center and white with a pink or lavender rim. Its a pretty elegant flower sometimes found in flower shops. Some varieties have doubled petals and look much like roses.

Lisianthus Discussion Page

The most common question I get is: "I just bought a lisianthus, now what can I do with it?". Well, you can leave it in the pot and grow it inside if you can put it on a sunny windowsill and water it every day or almost every day. Watch the leaves to see if they are wilting, if they are and you have been watering it enough move it to a larger pot. I use 16 ounce drinking cups for lisianthus, it seems an 8 ounce cup is too small. Make sure there are holes in the bottom of the pot or cup so excess water can drain out. Put the pot in a saucer that will collect the run off. Just because you get water draining out does not mean that the plant is getting enough moisture. When soil drys out it clumps together around the roots and leaves a gap between the soil and the wall of the pot. Water can quickly run down the sides to the bottom and then you think you've watered enough but you haven't. If the water runs out quickly let the water stand in the saucer for 5-10 minutes and then pour off the excess. These drinking cups I use for pots are white and so they reflect the heat away, I'd worry if I used a colored pot because it would heat up the soil more.

Give the plant some fertilizer, inside I use Miracle-Gro (15-30-15 with trace elements) or K-Mart has something equivalent and a little bit cheaper or use whatever you can get your hands on. Plants grow so much better with the trace elements I use half the recommended dose. If you want to encourage more blooms pick off the old flowers. If a whole stem is turning yellow and there are new green sprouts at the base of the plant cut off the old stem, new stems will grow up and flower. The Heidi hybrid I have grown inside can take 3 months or more between blooming cycles. During the winter they grow very little, apparently they need a long day to keep them growing and blooming.

You can also put your plant outside in a sunny location. Someone wrote to tell me that her's were doing OK with only about 4 hours of direct sun but I would try and give them more than that. I grow them from seed and put most of them up against a hot south facing brick wall and some of them wilt and die about the time the flowers come out. Maybe this location is too hot for them or maybe some just don't grow a good enough root system or maybe it is something else. Someone suggested that they like sandy soil and I know the soil here in Chicago isn't sandy and has a lot of clay in it so maybe that is my problem. Nematodes (like little worms) can damage the roots, here is a page describing the problem on lisianthus: Host status of specific crops

Outside I hardly fertilize at all and when I do I usually use a little spray-on kelp solution, the nutrients can be absorbed through the leaves. Really kelp alone (1-0-4 with trace elements) is not enough, use bonemeal as well and apply before the plants go in. DON'T use Miracle-Gro or any chemical fertilizer outside on ANY plants when it is hot and dry because chemical fertilizers are different kinds of salts and they only dry the plant out more.

Taller varieties need some kind of support. I use bent old metal coat hangers to prop them up. If you attach one to a plant bend back the end of the hangers so they won't have a sharp point that could damage your eye if you bend down to get a closer look. Attach a stem to the wire with a twist-tie. Or spokes from an old bicycle wheel are shorter but they work almost as well. Or use the bent coat hangers to form a crude fence. Or a temporary fix is to cut the flower stem and bring it inside and the plant will produce more flowers.

Lisianthus cannot survive a normal Chicago winter (USDA Zone 5, where the lows get to around -10 to -20F). In the winter of 2001-2002, the 10th warmest on record we had essentially a zone 7 winter (lows mostly no less than 0 to +10F except one night of -7) and maybe 20% of the plants survived.

To cope with winter you have two choices. One, dig them up and put them in pots inside. When I've done this they are simply not inclined to grow much over the winter probably because they are not getting enough light but they do start shooting up as the days get longer and I've had them blooming by the end of April. After blooming you can cut them back and put them outside.

Second, if you leave the plant outside collect the seeds for next year. The seeds form in a pod that looks much like a miniature melon and there are a very large number of very tiny seeds. I leave the seed pods on the plant until after some frosts and freezes and the pods turn brown. When a seed pod is brown you know it won't grow any more so it is safe to pick the seeds. I have picked seeds from green seed pods (the seeds were moist and white) and had them sprout but I am sure that waiting is the safest thing to do especially since the pods tend to stay closed so you won't lose many, if any seeds. Note though, that if you collect seeds this way year after year you will eventually lose the characteristics of the well-bred hybrids and get closer and closer to the wild type of plant. One surprise that came up was a plant that had white flowers with deep purple centers, a color combination that no one advertises. The seeds I've collected last at least a couple of years.

If you want to grow them from seed note that it takes a long time to get plants to the blooming stage from seed, about 4.5 months or more so plan accordingly. The plants I've started in January and the plants I start in March all seem to start blooming around the middle to the end of of July. I had some plants come up all by themselves in the garden from seed that simply fell to the ground however they bloom very late in the season. Plants I started in August and kept inside on the windowsill won't bloom until February or so and then there have not been very many flowers on these plants.

Lisianthus seeds are extremely small and some packets of lisianthus seeds have the seeds coated to make them larger and easier to handle. If they are coated they will look like round balls and the coating will melt quickly when it comes in contact with water. If you spill some seeds out on a white piece of paper you can use a pointed object like a small screwdriver to pick them up. Dip the tip of the screwdriver in a drop of water and then pick up a seed to deposit on the soil.

The most conventional thing you can do to start seeds is to start them in small pots, like 8 oz. styrofoam coffee cups with holes punched in the bottom. Fill it with potting soil (less chance of weeds coming up, everything that comes up will be lisianthus), soak the soil from top and bottom, and sprinkle a few seeds on the top. Cover with something clear like plastic wrap to hold the moisture in and let light in. Keep it out of direct sun, if it is covered and in direct sun the seeds will cook. You can put the cups on a north facing windowsill where you don't get direct sun. If you need to water, do it very gently so as not to disturb the seeds. You can water from the bottom or mist with water or you can water from the top by dripping one drop at a time onto the surface. After about 9 days the seeds will start sprouting and you can take the cover off during the day and expose them to more sun but keep the soil damp. If you have a lot of seedlings going you'll have to get rid of some but you can have two or three per pot if you like. If you attempt to do this in a single large pot it is difficult to separate the plants when they get bigger. They form very long and thin roots and carving them out of them will do a lot of damage to the roots and cause they to wilt after being transplanted. If you keep them wet after transplant they will recover but you're better off not having this problem in the first place.

I've also started them by placing seeds into Park's Starts cylinders (Park is at: These cylinders are like foam rubber and they hold a lot of water. They have a large hole in the center for a seed however lisianthus need light and it is best to place the seeds in a small nook or cranny on top. Thompson and Morgan (at has something similar but with larger squares instead of small cylinders. Place one or two per cylinder and water from the bottom so you don't disturb the seeds. If you drip water on from the top you will wash some down the sides of the cylinders, you can pick them out when they start to sprout but you might as well avoid that chore. You can put plastic wrap over the top to minimize the need for watering however keep them out of the sun, a north window that gets no sun will do. If you leave them in the sun with the plastic wrap on you are liable to cook the seeds. Using Park's Starts cylinders or Thompson and Morgan cubes is a really neat method because you can pack a large number into a small area and when they get large enough you can pop them directly into the ground or, if it is still too cold put them in 8 oz. styrofoam coffee cups.

If you're in a cold climate and you start them inside then when the weather warms up start taking them outside to get them used to the colder temps and direct sunlight. After a few days of this you can stick them in the ground if you think frosts and freezes are finished for the season. I've put them in the ground when it was still cold and they have survived near freezing conditions.

Here are some seed sources from 2003 catalogs:

Some plants stay small and weak and have only a few flowers while others are more robust and have up to about 18 flowers. Most Heidi hybrid plants bloom for about 6 weeks. Aloha red seems to bloom longer. The new variety, Forever Blue is supposed to bloom "continuously". When I tried Forever Blue in 2002 they did not bloom continuously, they had a good first bloom and then they stopped for a while before blooming continuously at a lower rate and they did continue to grow and bloom through frosts. If it's the middle of the summer feel free to cut the flower stem and bring the flowers indoors because more stems and flowers will form on the lower leaves that are left behind but note that the next batch of flowers will still take a long time to get to the blooming stage. In some cases more shoots will come up from the base of the plant and produce more flowers even without cutting back the original stem.

You can also increase flowering by pinching back the tops of the plants when they are still small, say 6 to 8 inches. This forces more side shoots to form and you'll get more flowers.

Once in the ground you can still have problems. First there was one report in rec.gardens that they resent having their roots disturbed. Second I've had trouble with plants on the hot, sunny, south side of the house. About the time the flowers come out some plants will wilt somewhere between a little and a lot. In case of a lot of wilting you might as well cut the flower stem off and stick it in a vase because in my experience the plant is doomed. When I've dug up the remains of these wilting plants I've found out that the roots are in poor shape making me that that something is attacking the roots or the roots never were very well-developed to start with. Due to this wilting problem I tend to water almost every day for plants on the hot south side of the house. Most of my plants have gone in this hot spot and only a few have gone into a garden area surrounded by many other plants. The few that have gone into the not-so-hot spots have not wilted so far so it may well be that my problem is the heat. If you look at the link below it says the best temperature for the plants is 15-25C (59 to 77F).

There is another way to propagate the plants. I had a pink Heidi hybrid that I dug out of the ground and kept over winter inside on a windowsill. By summer I cut it back and the roots were exposed to sunlight and after a while the roots developed leaves in 4 places. After a while I cut them out and put them in Park's Starts cylinders, they bloomed inside the following Spring.

Here are some articles on growing lisianthus:

Here are some additional photos:

If you have any questions or comments, write me.

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