How to Grow Lobelia Rosamond
Lobelia Rosamond
Lobelia erinus 'Rosamond'
flowerLobelia Rosamond is a compact, mounding annual flower featuring deep crimson-red blooms with striking white centers that create a bicolor effect. This dwarf cultivar grows 4-6 inches tall and produces masses of small flowers throughout the growing season, making it ideal for borders, containers, and hanging baskets.
When should you plant Lobelia Rosamond in your zone?
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Example Lobelia Rosamond timeline · Pittsburgh, PA (Zone 6b)
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Plant Lobelia Rosamond
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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First Lobelia Rosamond blooms
Around Jun 1≈ 45 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Lobelia Rosamond dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 2-11 as an annual; grows as a perennial in zones 9-11
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Seed germination
7-14 daysTiny seeds sprouting, requiring light exposure and warm temperatures (65-75°F)
Keep soil consistently moist but not waterlogged. Provide bright light (grow lights or sunny window). Do not bury seeds.
Seedling
2-3 weeksSmall plants with 2-3 true leaves developing; very delicate and tender
Maintain humidity and warmth. Provide bright light to prevent leggy growth. Water gently from below when possible.
Vegetative growth
3-4 weeksPlant develops bushy, mounded form with many stems and foliage reaching 4-6 inches tall
Pinch back growing tips early to encourage branching and fuller shape. Ensure consistent moisture and feed every 2-3 weeks with dilute fertilizer.
Flowering
6-12 weeks until frostDense clusters of small crimson-red flowers with white centers appear across the entire plant
Deadhead spent flowers to encourage continuous blooming. Maintain consistent watering. Reduce fertilizer nitrogen to promote flowers over foliage.
End of season
Until first frostFlowering continues until first frost kills the plant (zones 2-8) or plant becomes woody and less floriferous (zones 9-11)
In mild zones, cut back by half to rejuvenate for next season. In cold zones, enjoy until frost or remove and compost.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with water to dislodge; use insecticidal soap or neem oil if severe. Encourage beneficial insects like ladybugs.
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Hand-pick in early morning or evening. Use beer traps or copper tape barriers around containers. Apply food-grade diatomaceous earth.
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Increase humidity and water spray on foliage. Use neem oil or miticide if infestation is heavy. Remove heavily infested leaves.
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Use yellow sticky traps to monitor and control. Spray undersides of leaves with insecticidal soap or neem oil.
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Improve drainage by amending soil with perlite. Avoid overwatering. Remove affected plants to prevent spread.
Uses
Container and hanging basket displays
OrnamentalLobelia Rosamond's compact, trailing habit and prolific flowering make it perfect for window boxes, hanging baskets, mixed containers, and small space gardens. The bicolor red and white flowers create striking visual impact. [source]
Border edging and ground cover
LandscapeIts low, mounding growth habit (4-6 inches) makes it ideal for edging flower beds, creating colorful borders, and filling gaps between larger plants. Creates a carpet of color in garden designs. [source]
Pollinator attraction
WildlifeLobelia flowers attract hummingbirds, butterflies, and bees throughout the blooming season, supporting pollinator populations in gardens. [source]
Cut flower arrangements
HouseholdThe delicate stems and bicolor flowers can be used in small floral arrangements and bouquets, though they are more delicate than typical cut flowers. [source]
Harvest Tips
Not harvested; instead, deadhead (pinch off) spent flower clusters to promote continuous blooming throughout the season. Collect seeds at end of season before frost for next year—allow flowers to dry on plant, then harvest seed pods.
Fun Facts
- 🌱 Lobelia Rosamond is named for its distinctive deep red color reminiscent of traditional rose shades, and the 'Rosamond' cultivar was bred specifically for its compact habit and large bicolor flowers compared to wild Lobelia erinus.
- 🌱 Lobelia seeds are among the tiniest flower seeds, with approximately 750,000 seeds per ounce, which is why they're surface-sown rather than buried.
- 🌱 In warm climates (zones 9-11), Lobelia Rosamond can behave as a short-lived perennial or self-seed readily, returning year after year if conditions are favorable.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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