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Hybrid Lobelia

Lobelia x speciosa
Also known as: Cardinal Flower

Hybrid Lobelia is a flower in the Campanulaceae family. It grows best in full sun to part shade with medium to wet moisture, and is listed for USDA zones 6-10. Plants reach maturity about 77–84 days after planting and sit about 6 inches apart.

Varieties

1 from True Leaf Market · sorted by days to maturity
  • Vulcan Red77–84 days

    Non-GMO; Container; Annual; Perennial

    77-84 Days to maturity. Lobelia speciosa. Vulcan Red Lobelia Seeds. Non-GMO, open-pollinated, Premium Quality Seeds, perennial. Open Pollinated. Vulcan Red Cardinal Flower seeds deliver exotic, early-blooming, and easy-to-grow lobelia plants for especially hot, humid gardens across the country. Vulcan Red lobelia seeds mature into a robust, columnar form for indoor planters or as trimming to your flower bed. Vulcan Red grows one of the most dense and unique blooming stalks in any garden, and certainly one of the most vibrant. Vulcan Red lobelia seeds are the perfect eye-catching centerpiece to your summertime baskets, bouquets, and arrangements. Pelleted seeds with an inert clay coating for easier planting and visibility.

    View on True Leaf Market
Family
Campanulaceae
Category
Flower
Form
Bush
Lifecycle
annual or perennial
Zone
6-10
Height
2–2.6666666666666665 ft
Spread
0.8333333333333333–1.1666666666666665 ft
Sun
Full sun to part shade

Plant spacing

4 plants per square footSquare-foot planting diagram: a 1-foot square divided into a 2-by-2 grid holding 4 hybrid lobelia plants spaced 6 inches apart.
4 plants per square foot

In a square-foot bed, space hybrid lobelia about 6 in apart — that fits 4 plants in each 1-foot square (2×2). Wider rows or containers space the same.

Water
Medium to wet

Plan your hybrid lobelia planting

Add hybrid lobelia to a free GardenDraft plan and get sow, transplant, and harvest dates computed for your ZIP code — with a drag-and-drop bed layout and reminders when it’s time to plant.

Start your free plan →

At a glance

Days to harvest
77–84 days
From transplant or sow to first harvest
Harvest style
Harvest once
One main harvest
After harvest
Use within days
Quality eases off after peak
Frost tolerance
Hardy · to ~-5°F
Lowest temperature the foliage usually survives
Germination
~55%
Typical minimum germination rate

Growing timeline

When to plant and harvest hybrid lobeliaPlanting timeline for hybrid lobelia, relative to last frost: start indoors from 9 weeks before last frost to 1 week after last frost; grow from 1 week after last frost to 12 weeks after last frost; harvest from 12 weeks after last frost to 13 weeks after last frost.Start indoorsGrowLast frostTransplant
Start hybrid lobelia indoors ~10 weeks before transplanting 1 week after last frost; first harvest 12 weeks after last frost.
Seed to transplant
56-70 days
Outdoor planting
7 to 14 days vs frost
Propagation
Seed
Schedule anchor
Last Frost

Care & troubleshooting

No curated care & troubleshooting advice for hybrid lobelia yet. Our extension-sourced library currently focuses on common edible crops; we're expanding it over time.