Great Blue Lobelia (Lobelia siphilitica)

Common names:
Give a thumbs up Great Blue Lobelia
Give a thumbs up Blue Cardinal Flower

Botanical names:
Lobelia siphilitica Accepted
Lobelia siphilitica var. rosea Synonym

General Plant Information (Edit)
Plant Habit: Herb/Forb
Life cycle: Perennial
Sun Requirements: Full Sun to Partial Shade
Water Preferences: Wet
Wet Mesic
Mesic
Minimum cold hardiness: Zone 4b -31.7 °C (-25 °F) to -28.9 °C (-20 °F)
Plant Height: 3 to 5 feet
Flowers: Showy
Flower Color: Blue
Bloom Size: Under 1"
Flower Time: Late summer or early fall
Underground structures: Taproot
Uses: Erosion control
Water gardens
Will Naturalize
Wildlife Attractant: Bees
Birds
Hummingbirds
Resistances: Deer Resistant
Rabbit Resistant
Flood Resistant
Humidity tolerant
Toxicity: Other: milky juice from plant considered somewhat poisonous.
Propagation: Seeds: Provide light
Stratify seeds: 2 months cold moist treatment
Depth to plant seed: Seed is tiny. Do not cover with soil; keep moist.
Can handle transplanting
Propagation: Other methods: Division
Pollinators: Bees

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A Beautiful Day in the NeighborhoodA Beautiful Day in the Neighborhood
July 13, 2014

The Nature Conservancy calls Tennessee the most biologically rich of all the inland states. As I walk through my property and neighborhood, I see many exotic plants. Fortunately, I also see an abundance of native plants.

(Full article33 comments)
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Photo gallery:
Location: VermontDate: 2017-09-08
By Char
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Location: My garden, Pequea, Pennsylvania, USADate: 2018-08-11Do you see the tiny pollinator?
By csandt
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Location: Indiana zone 5Date: 2014-08-21
By gardengus
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Location: central IllinoisDate: 8-25-19
By jmorth
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Location: Indiana zone 5Date: 2014-08-03emerging flower head
By gardengus
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Location: Indiana zone 5Date: 2014-08-21
By gardengus
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Image
By SongofJoy
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Location: Kamloops, BC, CanadaDate: 2012-10-21
By Gilli
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Location: central IllinoisDate: 9-20-11
By jmorth
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Location: Nora's Garden - Castlegar BCDate: 2016-07-27 9:19 am. A beautifully structured blue blossom.
By HemNorth
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Location: Mentor on the LakeDate: 2018-08-03
By Samlav
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Location: Tennesseephoto courtesy of Sunlight Gardens, www.sunlightgardens.com
By SongofJoy
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Location: central IllinoisDate: 2010-09-08
By jmorth
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Location: central IllinoisDate: August 2009
By jmorth
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Location: central IllinoisDate: 8-31-07
By jmorth
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Photo Courtesy of Prairie Nursery. Used with Permission
By Joy
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Location: Allentown, PennsylvaniaDate: 2015-08-06
By plantrob
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Location: central IllinoisDate: 2016-07-19
By jmorth
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Location: Nora's Garden - Castlegar BCDate: 2016-05-10 6:19 pm. Always a welcome sight to see the self-seeding of this
By HemNorth
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Location: central IllinoisDate: 2016-09-27
By jmorth
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Location: ILDate: 2009-09-22
By molanic
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Location: Chicago Botanic GardenDate: 2018-09-01
By jmorth
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Location: Chicago Botanic GardenDate: 2018-09-01
By jmorth
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Location: central IllinoisDate: 8-31-06behind coleus
By jmorth
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Location: central IllinoisDate: 9-8-06w/ night moth
By jmorth
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Location: Kalama, Wa.
By Joy
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Location: central IllinoisDate: 2012-07-26
By jmorth
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Location: central IllinoisDate: 2013-09-01
By jmorth
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Location: central IllinoisDate: 2011-09-10
By jmorth
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Location: central IllinoisDate: 2011-09-20
By jmorth
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Photo Courtesy of Lazy S'S Farm Nursery.
By Joy
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Photo Courtesy of Lazy S'S Farm Nursery.
By Joy
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Location: central IllinoisDate: 2015-09-05
By jmorth
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Location: central IllinoisDate: 2015-09-09
By jmorth
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Location: central IllinoisDate: 2015-10-20
By jmorth
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Location: central IllinoisDate: 2016-07-19
By jmorth
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Location: the Lurie Garden in Chicago, IllinoisDate: 2013-08-13nice group in bloom
By ILPARW
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Location: West Chester, PennsylvaniaDate: 2016-08-29group of blue and white bloomers in landscape
By ILPARW
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Location: Glen Ellyn, IllinoisDate: 2012-08-15group in bloom with boulders
By ILPARW
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Location: Lancaster County, PennsylvaniaDate: 2013-07-26several plants in bloom in garden
By ILPARW
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This plant is tagged in:
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Comments:
Posted by ILPARW (southeast Pennsylvania - Zone 6b) on Feb 20, 2018 3:13 PM

This Great Blue Lobelia is a glorious perennial for moist or draining wet soils that prefers some partial shade, but can do full sun in moist soils. It is a long bloomer in August into early October. It is an easy and reliable plant, but it does not like strong completion from bigger plants. It often self-sows a lot, even getting seedlings into nearby pots. It is longer lived than the similar Cardinalflower. It is easy to transplant with shallow fibrous roots. In fact, I can pull plants right out of the ground without digging for transplanting and then just plant them as is. Some are sold by many conventional, classic nurseries and by most native plant nurseries. I have not seen this species sold by big box or Home Depot-Lowes stores. I find it occasionally planted around in yards; it should be used much more. It is a very easy perennial. Its native range is from Maine to southern Manitoba to Colorado into Texas through Alabama to North Carolina.

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Posted by jmorth (central Illinois) on Nov 10, 2011 1:41 AM

Habitat - Wildflower that grows in wet ground, marshes, fens, and open woodlands along streams.
Mesquakies Indians thought it could heal failing relationships if added, unbeknownst to the quarreling couple's food.
Some Indians believed it a cure for syphilis. The 'secret' was sold to some Europeans who took it to Europe where it failed to perform to expectations.
Genus named in honor of a 16th century herbalist, Matthias de l'Obel.

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Posted by Catmint20906 (Maryland - Zone 7a) on Aug 24, 2014 6:29 AM

Great Blue Lobelia (Lobelia siphilitica) is a beautiful late-summer perennial native to eastern North America. Lobelia siphilitica has special value to native and bumble bees. It attracts several bee species, including digger, yellow-faced, green sweat, small carpenter, and bumble bees. Bumble bees in particular like to visit this plant and are its most frequent pollinators. This plant also supports conservation biological control by attracting beneficial insects to the garden. In addition, Great Blue Lobelia attracts hummingbirds.

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Posted by sallyg (central Maryland) on May 13, 2019 7:02 AM

I got this from a swap several years ago. The original plant grows in a very moist spot. I have moved a few into other garden sites as well. I can't say if it prefers one site over another. It has a lot of flowers, on which I noticed one tiny unusual type bee or wasp.

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Plant Events from our members
lovesblooms On January 25, 2015 Seeds sown
winter sown
Catmint20906 On July 17, 2015 Bloomed
aspenhill On May 7, 2016 Obtained plant
NGA Susan (Muddy1) - qty 3
MissMew On May 26, 2018 Plant Ended (Removed, Died, Discarded, etc)
MissMew On August 17, 2015 Obtained plant
nativeplants.ca
christine2 On May 25, 2019 Obtained plant
3 Humber Nursery Ont.
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Discussion Threads about this plant
Thread Title Last Reply Replies
What is this - growing all over! by apbleonard May 24, 2019 9:03 PM 2
Purple Wildflower ID Please by delirow Sep 15, 2018 3:10 PM 2
Is this Blue Lobelia - Lobelia siphilitica? by Linford Jul 30, 2018 8:45 AM 3
blogs ? by upat5 Dec 18, 2016 8:21 PM 10
Fall Swap Haves and Wants Thread by Catmint20906 Sep 9, 2016 9:21 PM 201
"Think Spring!" Seed Swap SUNDAY Jan 31 2016 by critterologist Mar 3, 2016 11:45 AM 109
2016 Garden Chat and Photos by ssgardener Feb 25, 2017 2:24 PM 1,945
Yardening in the Mid-Atlantic by Eric4home Jan 19, 2020 1:23 PM 3,202
Great Blue Lobelia (Lobelia siphilitica) by Swayback Aug 23, 2015 3:06 PM 3
Lobelia inflata by Catmint20906 Jul 20, 2015 5:45 AM 7

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