Eustoma grandiflorum! Lisianthus! If you’re a new grower here’s what you need to know:
Lisianthus flowers are very slow growing and best grown from plugs, versus seed. When choosing a variety to grow, note the group. Each grouping (Group 1, 2, 3, and 4) has a corresponding season in which they flower, which is daylight and heat dependent. Basically, you want these plants to have enough time in the ground to grow long stems before their time to flower–so choose accordingly. Lisianthuses love to be planted in the fall here in our zone and overwintered during our “cool season.” You can also plant them in the early spring!
When purchasing plugs, note how many come in a tray. The higher the number, the smaller the plants, and the more work they’ll require to get established. After planting 6 inches apart, overhead watering is needed until these plants root in and show some new, green growth. This takes a long time because, again, lisianthuses grow very, very slowly.
Lisianthus flowers have small, wispy, wimpy root systems and, therefore, must be kept thoroughly weeded. I can’t stress this enough. Once the plants are a few inches tall, pinch out the center above a set of leaves to get multiple stems per plant. Flower netting is needed to keep these plants standing upright in the garden. I hilled compost around my overwintered plants this year for some extra weed suppression, nutrients, beneficial microbiology, and stability.
Lisianthuses are susceptible to many soil-born diseases and should be carefully rotated in the garden each year (don’t grow them in the same spot as last year). I apply AACT (actively aerated compost tea) with the hope that the beneficial microbes will outcome the pathogenic ones. Increasing airflow between plants helps with disease prevention as well, and this is another reason why I space my plants 6 inches apart and choose a breezy location by a garden pathway whenever possible.
Lisianthuses will produce a second, shorter flush of blooms if you take the time to weed, feed, and water them consistently, and deeply after their first big flush.
Lisianthus flowers are not an extremely profitable crop for me, but it’s one I’ll continue to grow because lisianthuses can stand in as a focal flower, thrive in the summer heat (and doesn’t easily succumb to powdery mildew), produce many cuts in a small space, and have a remarkable vase life (10 to 14 days). Most importantly, I find these blooms beautiful, and I enjoy using them in my own design work and growing them in the garden.