perennial flower
Great blue lobelia
A blue companion to cardinal flower for moist shaded gardens.
Growing Profile
- Hardiness
- Zones 4a-9a
- Sun
- PartialFull
- Soil
- LoamClay
- Water
- High
- Deer pressure
- Not rated No deer-resistance category is assigned yet; treat browsing risk as local and variable.
- Black walnut
- Mixed or uncertain Use as a black walnut / juglone planning cue; tolerance varies by cultivar, soil, and distance from the tree.
- Planting depth
- Set the crown at the same level it grew in the nursery pot.
- Container min
- 2+ gal (good)
- Goals
- Pollinators & wildlifeCurb appeal & colorNative plants
Harvest & Use
- Window
- blue flower spikes in late summer
- Output
- 3-8 weeks of bloom/year
- First output
- 1-2 yrs
- Best for
- Pollinators & wildlifeCurb appeal & colorNative plants
Timing: blue flower spikes in late summer. This profile tracks 3-8 weeks of bloom/year with a harvest or display window of 2-5 weeks where defensible.
Plant photos
What it looks like in the garden
Use these photos to compare the plant's leaves, stems, flowers, fruit, and overall habit before you buy or plant.
Photos show a representative plant in the garden. Fruit color, size, and growth habit can vary by cultivar, season, nursery stock, and site.
Photo sources: John Rusk from Berkeley, CA, United States of America / Wikimedia Commons (CC BY 2.0)
Quantitative Profile
- Full output
- 2-3 yrs
- Mature size
- 1-5 ft H x 1-3 ft W
- Spacing
- 1-3 ft apart
- Planting depth
- Set the crown at the same level it grew in the nursery pot.
- Container min
- 2+ gal (good)
- Productive life
- 3-10 yrs
- Difficulty
- 1/5
- Reliability
- 4/5
- Data quality
- Medium profile, No pound-yield source
Pound return is the stock-style yield metric. These are planning ranges for comparing plants, not guarantees. Cultivar, rootstock, climate, soil, pruning, pest pressure, and wildlife can move actual results.
Planting Checklist
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Right-size container with drainage
Containers / Before plantingUse a container large enough for mature roots, with open drainage holes to prevent root rot.
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Expanding container potting mix
Containers / Before plantingUse a lighter container medium instead of dense garden soil in pots and grow bags.
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Hose timer
Watering / Install at plantingKeep new plantings and containers from drying out during establishment.
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Drip irrigation kit
Watering / Install at plantingDeliver steady root-zone moisture with less leaf wetness and less water loss.
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Organic mulch
Soil / After plantingHold soil moisture, suppress weeds, moderate soil temperature, and protect shallow roots.
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Hand trowel
Tools / Planting dayPlant starts, herbs, flowers, bulbs, and smaller container plants at the right depth.
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Shade cloth
Protection / Heat wavesReduce heat stress for cool-season greens, tender transplants, and containers in hot sun.
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Finished compost
Soil / Bed prepImprove bed structure and organic matter before planting annuals, perennials, shrubs, and trees.
Planting Strategy
- Planting depth: Set the crown at the same level it grew in the nursery pot.
- Container minimum: 2+ gal (good). Use 2+ gal per plant, or wider mixed containers with similar water needs.
- Start with one plant when testing fit in a new bed or container.
Risk Factors
- Match the site first: partial, full light, loam, clay soil, and high water.
- Use 1-3 ft apart as the first spacing model; adjust for hedges, trellises, containers, or local guidance.
- Plan around mature size: 1-5 ft H x 1-3 ft W.
- Native-plant matches are starting points; confirm regional nativity, straight-species versus cultivar status, and local invasive guidance.
- Local drainage, pests, chill hours, wildlife pressure, and microclimates can change the result.
Related Planning Guides
Comparable Plants
Sources & Methodology
This guide combines hardiness range, light, soil, water, harvest timing, traits, supplier links, plant relationships, and quantitative planning metrics. Pairings are screened for practical garden fit.
Quantitative values use extension and botanical-reference ranges where available. For less-studied cultivars, similar crops fill gaps conservatively. Ranges are intentionally broad so the profile stays useful without pretending to be exact.
Planning sources: NC State Extension Gardener Plant ToolboxMissouri Botanical Garden Plant FinderK-State Extension Master Gardener Handbook - Herbaceous PlantsUniversity of Maryland Extension - Types of Containers for Growing VegetablesIllinois Extension - Growing Vegetables in Containers
Supplier search: Amazon. Search links are not paid placements unless explicitly marked; affiliate listings may earn a commission. Last reviewed: 2026-05-31.