PlantFiles: Great Blue Lobelia
Lobelia siphilitica

I love this plant, but I warn others that given a wet location, it's an aggressive spreader. I planted one in a very wet area of my garden, and there are seedlings everywhere. They're all blooming, so at least there's that, and they are easy to pull out, so I thin them out periodically. I have some in a full sun, hot, dryish bed that does beautifully, but hasn't spread babies around. I absolutely love this plant though: a beautiful blue.

Intense blue flowers, on the violet side of the color. It mixes well with its sibling, cardinal flower (Lobelia cardinalis), with it similar bloom times and very intense, deep red flower. It doesn't draw hummingbirds like cardinal flower, but they do feed on it.

The plant file notes that it has above average water needs, but this isn't entirely accurate. As with many prairie natives, it can tolerate periods of drought, as it has very deep roots. It does best when it is in a low-lying spot, such as a swale or raingarden, with well-drained but occasionally flooded soil. Ours does fine going several weeks without any rain or watering once established.

A very pretty, easy to grow plant. Other names include Lobelia syphilitica, Blue Cardinal Flower, Great Lobelia, High Belia. Light aids germination of seeds.

The flowers attract bumblebees primarily. Less common visitors include hummingbirds, butterflies, and Halictid bees. The latter group of bees collect pollen only and are non-pollinating. Most mammalian herbivores don't eat this plant because the foliage contains several toxic alkaloids, chief among them being lobeline and lobelanine. These toxic substances produce symptoms that resemble nicotine poisoning. However, it has been reported that deer occasionally eat this plant, perhaps enjoying greater immunity to these toxic substances than other animals. The seeds are too small to be of much value to birds.

I bought mine in Spring at my favorite nursery in Oakland, I transplanted it in a new pot in semi-shade, got a lot of water, was beautifull, and very blue, I had never seen one before, new plantlets are growing at the base of the original and I can't wait to see it take off again.

This is native in my zone 5 area. We found several stalks of it this year growing in the weeds around our pond. It's in full sun, but has very wet feet. It shares the same terrain as our cattails.

We're going to try collecting seeds this year. It would look great in a mass planting. Ours grow in very narrow spikes with little lateral foliage or stalks.

It must spread by seed, but only a little. We find small growths of it here and there in our field.

Native to my area in southern Arkansas, this beauty thrives in intermittent stream beds, as well a in a pot on my sunny deck. Semi-shade deepens the intensity of the blue.

I have seen these grow on rock walls along river banks. They are spectacular and inspiring, to say the least!

I really like this particular variety - it shuffles itself around the planting bed and parks where it is happiest! It is not invasive (like goose-neck loosestrife), just puts a clump or two around the bed. And blooms just when the summer bloomers are fading! What a great plant!

Easy from seed--will even bloom a little the first year! Great for the butterflies and hummingbirds. The foliage is a handsome dark green. A group of these is just specatacular in the late summer garden.

This plant is much easier to please than the better-known Scarlet Lobelia, so that most gardeners should be able to find a place for it in their landscape. It tolerates full shade, but blooms much better in full to partial sun.

Native to North America, produces spikes of blue flowers in late summer. The plant grows well in moist to wet soils and so is useful near water. The plant may be short-lived but will tend to reseed.