On a whim, I picked up a 6 pack of lisianthus (Eustoma grandiflorum) at a local nursery several years ago. It was worth a try to see if they would survive the incredibly hot summers here in the low desert of Arizona. I wasn’t sure how to grow lisianthus, and was shocked when they grew well all summer and some returned the following spring! The beautiful rose-like blooms were a pleasant surprise.
Lisianthus is now a summer staple in my low desert Arizona garden. Learn how to grow lisianthus with these 10 tips.
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10 Tips for How to Grow Lisianthus
1. Plant lisianthus from plugs or transplants
- Lisianthus is tricky for seasoned nursery professionals to grow well from seed. Leave the sowing to the experts and purchase transplants or plugs. Local growers, nurseries, and online retailers may all sell lisianthus starts. Look for plugs or transplants that have buds beginning to grow to ensure flowers are on their way.
- Space lisianthus transplants about 6 inches apart. Most lisianthus plants grow tall, and spacing plants closely helps them support one another as they grow. Transplant plugs and transplants a little higher than soil level to avoid stem rot.
- For square foot gardening, plant 4 lisianthus per square.
2. Grow different varieties of lisianthus
- Lisianthus varieties vary in height and color.
- If you are growing lisianthus in containers, choose shorter varieties.
- Longer-stemmed types of lisianthus will require staking or netting to stay upright.
- Typical colors for lisianthus are cool tones of purples and pinks.
- Blooms are typically single or double types.
- Choose a variety you enjoy and that suits your needs.
3. Plant lisianthus at the right time
Plant lisianthus transplants in the spring after all danger of frost has passed.
The best time to plant lisianthus in the low desert of Arizona is from March through June. Planting it early in the season gives lisianthus plenty of time to become established before the heat of the summer in hot climate areas.
4. Give lithianthus the type of soil it needs to grow well
Lisianthus prefers a neutral or even slightly acidic soil. Soil that is too alkaline will cause yellow leaves and overall poor health. Aim for a pH between 6.5 and 7.0. This probe is a quick way to test your soil’s pH.
5. Choose a location with plenty of sunlight
Lisianthus is native to prairies and fields in the southern United States and Mexico and prefers warm, dry air. Cool humid locations may have difficulty growing lisianthus.
Choose an area in your garden to plant lisianthus that gets full sun. If you live in a hot summer climate like the low desert of Arizona, lisianthus benefits from some afternoon shade.
6. Water lisianthus correctly
- Lisianthus prefers moist, but not soggy soil.
- Avoid getting water on the leaves. Using a drip system is an effective way to water lisianthus.
- If fungus gnats are an issue, let the top inch of soil dry out a bit between waterings.
- Mulching soil will help retain moisture and keep weeds down.
7. Feed lisianthus as needed throughout the growing season
LIsianthus benefits from rich soil and regular feeding from a flower fertilizer that is higher in potassium than nitrogen (the middle number in the N-P-K formula is higher than the first number).
8. Encourage more blooms
After the first flush of blooms, cut the stems back all the way to the rosette. Water and fertilize well to encourage an additional flush of blooms. This results in a more uniform set of second blooms.
For a less drastic approach and continual blooms, deadhead spent blooms by cutting each bloom back to where it emerges from two sets of leaves. Plants should continue to send up flower stalks while temperatures are warm.
9. Maximize vase life for lisianthus blooms
- Harvest blooms in the morning when temperatures are coolest.
- Harvest once one or more of the flowers on the stem are open.
- Use sharp scissors or pruners to cut the stem just above the base of the plant.
- Strip all leaves below the water level in the vase.
- Recut stems before adding them to the vase.
- Replace water in the vase every few days as needed.
10. Grow lisianthus as a perennial if you live in a warm climate
This heat-loving flower grows well as an annual in most zones. However, lisianthus is actually a perennial and can be overwintered in warmer zones (zones 8-10).
To grow lisianthus as a perennial, cut back plants after the last blooms fade in the fall and mulch well with straw. Cooler zones may use row cover to prevent lisianthus from dying. New growth will emerge in the spring.
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