How to Grow Lobelia Regatta Lilac

Lobelia Regatta Lilac

Lobelia erinus 'Regatta Lilac'

flower

Lobelia Regatta Lilac is a compact, mounding annual flower prized for its delicate lilac-purple blooms and fine, feathery foliage. This cultivar produces abundant small flowers from late spring through fall, making it ideal for containers, hanging baskets, and garden edging. It's a tender annual that thrives in cool to moderate temperatures and blooms prolifically with minimal maintenance.

When should you plant Lobelia Regatta Lilac in your zone?

Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.

Get my Lobelia Regatta Lilac timeline →

Example Lobelia Regatta Lilac timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Lobelia Regatta Lilac

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. First Lobelia Regatta Lilac blooms

    Around Jun 16

    ≈ 60 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Lobelia Regatta Lilac dates for your own zip code.

Growing Conditions

☀️
Sun: Partial shade to full sun; 4-6 hours of sunlight daily; afternoon shade in hot climates (zones 8+)
💧
Water: Keep soil consistently moist but not waterlogged; water when top inch of soil is dry. Daily watering may be necessary in containers during hot weather. Avoid overhead watering to prevent fungal issues.
📏
Spacing: 6-8 inches
📅
Days to maturity: 60-90 days from seed to first flowers
🌱
Planting depth: Surface sow or press seeds lightly into soil; do not cover, as seeds need light to germinate

Soil

Type: Well-draining loamy soil with consistent moisture retention
pH: 6.0-7.0
Amendments:
Compost peat moss perlite for drainage

Growing Zones

Find your zone →

Thrives in zones 3-11 as an annual; perform best in zones 5-9 with moderate summer heat

3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b 11a

Sign up free to see if Lobelia Regatta Lilac grows in your zone — and get a personalized planting timeline.

Get my Lobelia Regatta Lilac timeline →

Growth Stages

1

Seedling

2-3 weeks

Tiny seeds germinate to produce delicate first leaves. Plants are fragile and very small.

Keep soil consistently moist under humid conditions. Provide bright light (not direct sun). Maintain 65-70°F for best germination (7-14 days). Avoid damping off by ensuring good air circulation.

2

Early Growth

3-4 weeks

Plants develop true leaves and begin forming a compact mound structure. Growth is slow initially.

Transplant to individual containers once true leaves appear. Gradually acclimate to brighter light. Begin dilute liquid feeding every 2 weeks. Pinch back once or twice to encourage bushiness.

3

Vegetative Development

3-5 weeks

Plant forms dense, bushy mound with increasingly thick foliage coverage.

Harden off transplants before moving outdoors. Plant outside after frost danger passes. Continue consistent moisture. Feed weekly with balanced or slightly higher phosphorus fertilizer. Pinching may continue for compactness.

4

Blooming

8-12 weeks or until frost

Plant becomes covered with abundant small lilac-purple flowers along the mound.

Deadhead spent flowers to encourage continuous blooming. Maintain consistent moisture and weekly fertilization. Reduce nitrogen to prevent excessive leaf growth at expense of flowers. Keep cool if possible; flowers fade in extreme heat.

5

Decline

Until frost

Flowering slows as temperatures cool in fall or plant succumbs to first frost.

In mild zones, deadhead to extend season. Plant will not recover if exposed to freezing temperatures. Remove at season's end. Save seeds from spent flowers if desired.

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

plants requiring dry soil conditions aggressive growers that shade delicate lobelias

Common Pests

  • Spray with insecticidal soap or neem oil; use strong water spray to dislodge. Introduce natural predators like ladybugs.

  • Increase humidity and mist foliage (avoid wetting flowers). Use neem oil or miticide if severe. Remove heavily infested leaves.

  • Use sticky traps for monitoring. Spray with insecticidal soap or neem oil weekly until controlled. Isolate infested plants.

  • Ensure excellent air circulation. Avoid overhead watering. Spray with sulfur or fungicide if needed. Remove affected leaves.

  • Prevent by using sterile seed-starting mix, ensuring good drainage and air circulation, avoiding overwatering, and maintaining proper temperature.

Uses

🍳

Not for consumption

Culinary

Lobelia is not edible and should never be consumed. It contains alkaloids that can cause gastrointestinal upset and other adverse effects. [source]

🏠

Container gardening and landscaping

Household

Lobelia Regatta Lilac is exceptional in hanging baskets, window boxes, and mixed containers where its cascading habit and profuse blooms create stunning displays. It's also ideal for garden edging, rock gardens, and as a groundcover alternative. [source]

🎨

Cut flowers and arrangements

Craft

While individual flowers are delicate, stems of lobelia flowers can be cut and used in small bouquets, corsages, or as filler in floral arrangements for a charming, cottage-style aesthetic. [source]

🦋

Pollinator attraction

Wildlife

Lobelia flowers attract bees, butterflies, and hummingbirds, making it valuable for supporting pollinator populations in gardens. The abundant blooms provide reliable nectar throughout the growing season. [source]

💊

Traditional herbal remedy (historical use only)

Medicinal

Historically, lobelia was used in traditional medicine by Native Americans and herbalists, but modern use is strongly discouraged due to its alkaloid content and toxicity. It should never be used medicinally without expert professional guidance. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Lobelia Regatta Lilac is an ornamental flower, not harvested for food or material. You can cut stems of flowers for small bouquets or arrangements; cutting encourages more blooming. Deadhead spent flower clusters regularly throughout the season to maintain continuous blooming and plant vigor. Allow some flowers to set seed late in season if you wish to save seeds for next year.

Fun Facts

  • 🌱 Lobelia Regatta Lilac is named 'Regatta' because the compact, uniform cultivar was bred to evoke the precision and uniformity seen in rowing competitions, making it one of the most reliable seed-propagated container lobelias.
  • 🌱 Lobelia flowers are highly attractive to hummingbirds, which feed on the nectar throughout summer and fall; a single hanging basket can attract dozens of visits daily.
  • 🌱 The 'Regatta' series comes in multiple colors (blue, white, lilac, pink) and all cultivars bloom earlier and more prolifically than older lobelia varieties due to intensive breeding for compact, uniform growth.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Join 30,000 gardeners planning their gardens with LizPlants.

Get your personalized Lobelia Regatta Lilac planting timeline

Tell us your zip code and we'll calculate exactly when to start Lobelia Regatta Lilac seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.

Get my Lobelia Regatta Lilac timeline →