How to Grow Great Lobelia
Great Lobelia
Lobelia grandis
flowerGreat Lobelia is a striking perennial wildflower native to the southeastern United States, known for its tall spikes of vibrant blue-violet flowers that bloom in late summer and fall. It thrives in moist, shaded woodland settings and can reach 3-4 feet in height, making it an excellent choice for naturalizing in rain gardens and wetland edges. The plant attracts hummingbirds and other pollinators while providing late-season color when many other flowers are fading.
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Example Great Lobelia timeline · Pittsburgh, PA (Zone 6b)
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Plant Great Lobelia
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 Great Lobelia blooms
Around Jul 16≈ 90 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Great Lobelia dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 5-9, with best performance in zones 6-8
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Seedling
2-3 weeksTiny seedlings with cotyledons and first true leaves emerging. Plants are delicate and require consistent moisture.
Keep seed starting mix evenly moist, provide bright indirect light, avoid damping off by ensuring good air circulation. Germination occurs at 65-75°F.
Vegetative Growth
4-6 weeksSeedlings develop into small plants with narrow, lance-shaped leaves forming an upright rosette. Stems become more robust.
Harden off transplants gradually before planting outdoors. Space plants 18 inches apart. Maintain consistent moisture and partial shade. Apply mulch to retain soil moisture.
Pre-flowering
2-3 weeksPlant reaches mature height (2-4 feet) and begins developing flowering spikes with tightly packed flower buds along the stem.
Ensure adequate moisture as flowering begins to form. Support tall stems with stakes if needed in windy locations. Continue partial shade conditions.
Flowering
4-8 weeksTubular blue-violet flowers open progressively along the spike from bottom to top, creating a showy inflorescence. Flowers are attractive to hummingbirds and pollinators.
Deadhead spent flowers to encourage continued blooming, though leaving some flowers allows self-seeding. Maintain consistent soil moisture. Flowers typically appear in August through October.
Seed Maturation & Dormancy
4-6 weeks then dormancyFlowers fade and seed capsules develop along the spent spike. Plant begins to decline after frost and enters winter dormancy.
Allow some flowers to remain for seed collection if desired. Cut back dead foliage in late fall or early spring. Ensure soil moisture decreases slightly in dormant season but doesn't dry out completely. Mulch around base for winter protection in colder zones.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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and
Hand-pick in early morning, use copper barriers or slug traps, maintain mulch away from stem base to reduce hiding spots
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Increase humidity and air circulation, spray with water to dislodge, use insecticidal soap if infestation is severe
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Improve air circulation, avoid overhead watering, remove affected leaves, apply fungicide if necessary
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Ensure adequate light and air flow, avoid dense planting, apply sulfur or neem oil if needed
Uses
Flower Garnish
CulinaryThe delicate blue-violet flowers can be used as an edible garnish for salads and desserts, providing visual appeal and a mild, slightly sweet flavor. Always ensure plants have not been treated with pesticides before consuming. [source]
Traditional Herbal Remedy
MedicinalHistorically used in Appalachian folk medicine and by Native Americans for respiratory support and general wellness. Contains alkaloids that have been studied for various therapeutic properties. [source]
Hummingbird & Pollinator Magnet
WildlifeThe tubular flowers are specifically adapted to attract hummingbirds and other nectar-feeding pollinators, making it an excellent native plant for supporting local pollinator populations during late summer and fall. [source]
Cut Flowers
HouseholdThe tall, elegant flower spikes make excellent cut flowers for late summer and fall arrangements, lasting 7-10 days in water. The unique blue-violet color adds depth and sophistication to floral displays. [source]
Shade Garden Design
CraftA key plant for naturalizing in woodland gardens, rain gardens, and moist shade areas, providing late-season color when many perennials are dormant. Integrates beautifully in native plant landscapes and wetland restoration projects. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
For cut flowers, harvest spikes in the morning when the lower flowers are open but upper buds remain tight. Cut stems at the base. For seed collection, allow flowers to fade on the plant, then harvest capsules when they turn brown and dry (typically September-October). Hang upside down in a paper bag to dry and collect seeds.
Fun Facts
- 🌱 Great Lobelia was used by Native Americans and early settlers for medicinal purposes, earning it the folk name 'Indian tobacco' due to the alkaloid content in its leaves.
- 🌱 The plant's flowers are specifically adapted to hummingbird pollination, with the tubular shape and blue-violet color being highly attractive to ruby-throated hummingbirds during their late-summer migration.
- 🌱 Lobelia grandis can self-seed readily in moist conditions, allowing it to naturalize and spread throughout suitable areas, creating stunning drifts of blue-violet color in rain gardens and wetland margins.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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