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Lobelia siphilitica

Lobelia siphilitica
great blue lobelia

Common name great blue lobelia
Family campanulaceae
Life cycle perennial (Z3-9)
Flowers blue or white (summer)
Size 18-30"
Light sun-part shade
Cultural notes moist soil
From seed Flowers first year from seed sown indoors early.
detailed seed-starting info below

The parent of several common lobelia hybrids, great blue lobelia is worth growing on its own merits. It can't stand dry soil (although it's probably a bit more drought-tolerant than L. cardinalis). Our first specimen was in an unfortunate location, overshadowed by hardy hibiscus by the time it bloomed. It eventually succumbed. A few years ago, I started a new batch from seed. I was expecting the blue form, but to my surprise, they flowered white in August. Charming for sure, but I think I prefer the regular species, so I re-established that from seed as well.

Lobelia siphilitica

We left this plant behind in our Pennsylvania garden (and wish it well); we don't grow it in Houston.

Seed for this plant is included on my seed trade list

One or more images of this plant are included in my stock photo catalog

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PlantLinks to other web pages about Lobelia siphilitica

Seed-starting details for this plant

  1. Seed from '04 garden. Baggy 65F with light (2%G, 17d)
  2. Seed from '08 trade. Baggy 70F with light (12%G, 9-40d)
  3. Same seed as above (labeled 'Blue'). Baggy 70F with light (~50%G, 12-20d)

Not sure if seed had low viability or if cold treatment is required. Tom Clothier suggests a temperature of 71-75F, so maybe my attempt was at too cool a temperature.

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