Lobelia in Zone 6B — Great Plains

Lobelia, with its masses of vibrant blue flowers, is a fantastic addition to any Great Plains garden. It thrives in our sunny climate, adding a splash of color to borders, containers, and hanging baskets. The profuse blooms are a welcome sight, and the plant's spreading habit fills in nicely.

While the Great Plains throws its share of extreme weather at us, timing your Lobelia planting right can help you dodge the worst of it. With our 198-day growing season, starting seeds indoors or buying transplants sets you up for success.

Starting Lobelia from seed indoors is an option, but honestly, given the tiny seeds and slow growth, you might be better off buying starts from a local nursery. If you're determined to start from seed, begin in early to late February, about 10 weeks before you plan to transplant.

Use seed trays with a good seed-starting mix. Keep the soil consistently moist by bottom watering – set the tray in a shallow dish of water and let the soil soak it up from the bottom. This prevents damping off. Spring weather can be variable, so ensure they have a consistent source of warmth and light.

Transplant your Lobelia seedlings outdoors in late April through late May, once the risk of frost has passed. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week.

Space plants 4-6 inches apart. Our weather can be unpredictable this time of year, so keep an eye on the forecast for late frosts or sudden temperature swings. Be prepared to cover your transplants if needed. Given how small the seeds are and how slowly they grow, buying starts is often the easier route for Plains gardeners.

Lobelia needs consistent moisture, especially in our hot, sometimes dry Great Plains summers. It's definitely not drought-tolerant, so regular watering is key.

During the peak of summer, when temperatures soar, you'll likely need to water deeply several times a week, potentially every other day. The finger test is your friend: stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Aim for about an inch of water per week, either from rainfall or irrigation. Water at the base of the plants to avoid wetting the foliage, which can lead to fungal issues in our low-to-moderate humidity.

Signs of underwatering include wilting leaves and dry, crispy edges. Overwatering can cause yellowing leaves and potentially root rot. A layer of mulch, like shredded bark or wood chips, helps retain moisture and regulate soil temperature, which is especially helpful in our variable climate.

Lobelia needs minimal pruning, but a little maintenance can keep them blooming all season long. When flowering slows down in midsummer, shear back the plants by about half.

This encourages fresh growth and a new flush of flowers as the weather cools in the fall. Don't be afraid to cut them back – they're resilient. As the first frost approaches in late October, you can let the plants go. They won't survive our winters, so there's no need to protect them.

Lobelia isn't really a "harvest" crop in the traditional sense. You're growing it for its beautiful, continuous display of tiny blue flowers. Expect the first flush of blooms in late June through mid-August, about 65 days after planting.

The more you enjoy the flowers in the garden, the better! Deadheading spent blooms can encourage continued production, but it's not strictly necessary. As the end of the season approaches and the first frost threatens in late October, simply enjoy the last of the blooms.

Lobelia can face a few challenges in the Great Plains:

Dies Back in Extreme Heat

• What it looks like: The plant appears wilted, scorched, and may stop flowering or even die back completely during the hottest part of the summer.
• What causes it: Our intense summer heat, especially when combined with dry spells, stresses the plants beyond their tolerance.
• How to fix/prevent it: Provide afternoon shade, especially during the hottest part of the day. Water deeply and consistently. Mulch around the base of the plants to help retain moisture and regulate soil temperature. If plants do die back, don't give up on them – they may rebound when temperatures cool.

Damping Off from Overwatering

• What it looks like: Seedlings or young transplants suddenly wilt and collapse at the soil line.
• What causes it: Overwatering, especially in cool, damp conditions, creates a breeding ground for fungal diseases that attack young plants.
• How to fix/prevent it: Use a well-draining potting mix. Water seedlings from the bottom to avoid wetting the foliage. Ensure good air circulation around plants. Avoid overcrowding.

Slugs

• What it looks like: Irregular holes in leaves, especially low-growing plants. Silvery slime trails on leaves and soil. Damage worse at night and in wet weather.
• What causes it: Gastropods that feed at night in moist conditions. Hide under mulch, boards, and debris during the day.
• How to fix/prevent it: Beer traps (shallow dish of beer sunk into soil). Iron phosphate bait (pet-safe). Remove hiding spots. Water in morning so soil surface dries by evening. Copper tape around beds. Diatomaceous earth around plants.

Great Plains Specific Challenges: The combination of intense heat, low-to-moderate humidity, and variable rainfall in the Great Plains can be tough on Lobelia. Consistent watering is crucial to prevent drought stress. Providing some afternoon shade can also help them thrive.

Lobelia makes a great companion plant in the Great Plains garden. Plant it near tomatoes and peppers; its delicate flowers attract pollinators that will also benefit your vegetable crops. The spreading habit of Lobelia also makes it a good ground cover around taller plants, helping to suppress weeds and retain moisture.

Lobelia also works well with lettuce. The Lobelia provides a bit of shade, which can keep the lettuce from bolting in the heat. Avoid planting Lobelia near anything that requires very dry soil, as its moderate watering needs could create overly moist conditions for those plants.