Lobelia in Zone 9B — Florida

Lobelia, with its masses of tiny, vibrant blue flowers, makes a beautiful addition to any Florida garden. It's perfect for adding a pop of color to borders, containers, or hanging baskets, and it thrives during our cooler months, when many other plants are struggling in the heat. Plus, seeing those blooms after the summer heat is so rewarding.

While Florida gardening has its challenges – extreme humidity, sandy soil, and the occasional hurricane – Lobelia's growing season aligns perfectly with our reversed seasons. We can plant in fall, harvest in winter, then let it rest during the summer slow season. With our 344-day growing season, you've got plenty of time to enjoy these beautiful blooms.

Starting Lobelia indoors is an option, but honestly, with their tiny seeds and slow initial growth, it can be a bit tricky. It's often easier to buy starter plants from a local nursery. However, if you're up for the challenge, you can start seeds indoors from mid-November through early December, giving them about 10 weeks to get a head start before transplanting.

Use seed trays with a good seed-starting mix and provide warmth and light. A heat mat can help with germination. Bottom watering is key to prevent damping off and keep the delicate seedlings happy. Remember, our spring character is reversed, so you're starting these as things cool down.

Transplant your Lobelia seedlings outdoors from early February through early March. Before you put them in the ground, harden them off for about a week by gradually exposing them to outdoor conditions. This will help them adjust to the Florida sunshine and breezes.

Space them about 4-6 inches apart in well-draining soil. Because the seedlings are so small, handle them carefully. Honestly, buying starts is often the way to go. Keep an eye on the weather – those late cold snaps can still happen, so be ready to cover them if needed.

Lobelia needs consistent moisture, especially in our sandy Florida soil. The key is to keep the soil consistently moist, but not soggy. They are definitely not drought-tolerant.

During our cooler months (fall through spring), water deeply about 1 inch per week, depending on rainfall. Use the finger test – stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Water at the base of the plants to avoid getting the foliage wet, which can encourage fungal diseases in our humid climate. In the wet-summer, you may not need to water at all!

Signs of underwatering include wilting and dry, crispy leaves. Overwatering can lead to yellowing leaves and root rot. A layer of pine straw mulch can help retain moisture and suppress weeds, but don't pile it up against the stems.

Lobelia requires minimal pruning, making it a low-maintenance addition to your garden. The main thing to remember is that they tend to slow down on flowering in the hottest part of midsummer.

When flowering slows down, shear the plants back by about half. This encourages fresh growth and a new flush of flowers when the weather cools down in the fall. As the first frost approaches around late December, you can let the plants fade naturally or remove them to prepare the bed for something else.

Lobelia isn't exactly a "harvest" crop in the traditional sense. These are ornamental flowers, so you're harvesting beauty and enjoyment in your garden. Expect the first flush of blooms from early April through late May, about 65 days after transplanting.

The "ripeness" indicator is simply when the plants are covered in masses of tiny blue flowers. To encourage continued production, deadhead spent flowers regularly. Just snip off the faded blooms to keep the plants looking tidy and promote new growth. As the weather cools towards late December, the plants may slow down or stop flowering. At this point, you can either let them fade or remove them.

Here are a few common problems you might encounter growing Lobelia in Florida:

Dies Back in Extreme Heat

• What it looks like: The plant wilts, leaves turn brown and crispy, and overall growth slows or stops completely.
• What causes it: Lobelia prefers cooler temperatures and suffers in Florida's summer heat.
• How to fix/prevent it: Provide afternoon shade, especially during the hottest months. Water more frequently to keep the soil consistently moist. Consider moving container plants to a cooler location. Sometimes, they just need a break and will bounce back when the weather cools.

Damping Off From Overwatering

• What it looks like: Seedlings suddenly collapse and die, often with a fuzzy, mold-like growth at the base of the stem.
• What causes it: Fungal diseases thrive in overly moist conditions, especially in our humid climate.
• How to fix/prevent it: Use a well-draining seed-starting mix. Water from the bottom to avoid wetting the foliage. Provide good air circulation. If damping off occurs, remove affected seedlings immediately to prevent it from spreading.

Slugs

• What it looks like: Irregular holes in leaves, especially on low-growing plants. Silvery slime trails on leaves and soil. Damage is worse at night and in wet weather.
• What causes it: These gastropods feed at night in moist conditions. They hide under mulch, boards, and debris during the day.
• How to fix/prevent it: Use beer traps (shallow dish of beer sunk into the soil). Apply iron phosphate bait (pet-safe). Remove hiding spots like mulch close to the stems. Water in the morning so the soil surface dries by evening. Consider copper tape around beds or diatomaceous earth around plants.

Florida-Specific Challenges: Our hot heat, very-high humidity, and wet-summer rainfall create a perfect storm for fungal diseases. Good air circulation, proper watering techniques, and choosing disease-resistant varieties are key to success.

Lobelia can be a great companion plant in your Florida garden.

Good companions:

• Tomato: Lobelia can attract beneficial insects that prey on tomato pests.
• Pepper: Similar to tomatoes, Lobelia attracts beneficial insects that help keep pepper plants healthy.
• Lettuce: Lobelia provides shade and helps retain moisture for lettuce, which prefers cooler conditions.

Bad companions:

• Avoid planting Lobelia near plants that prefer very dry conditions, as its need for consistent moisture could lead to problems for those neighbors.