Singing the Blues: Tiny but addictive lobelia shows off its many hues

Lobelia is one of those tiny but addictive plants that you can find at almost any nursery. For a couple bucks, you can get a fix with six small plants to tuck into pots, corners and flower beds. At that price, who can’t help but pop these puffy blue annuals into every nook and cranny?

Lobelia erinus is the fancy name for the common annual. But I beg to argue with the annual status. In some warm sandy areas, lobelia will sprout time and again from the same roots every year. I have had one sapphire mound for four years now. I hack it back in the fall and it pops again with the daffodils.

However, this time of year in the Rio Grande Valley, garden experts recommend holding off on planting these colorful additives. At least in the Valley, lobelias are best left for fall, said Cecile Waugh, owner of Waugh’s Nursery in Pharr.

Lobelias do require good timing, she said, but offer amazing color to mixed potted plants.

“They are not nearly as popular (in the Valley) as they should be,” Waugh said. “Blue lobelias offer the brightest deep blue of any other plant.”

Despite its delicate appearance, lobelia is no slouch. Good drainage seems the key to success. Lobelia hails from South Africa, which has a Mediterranean climate — wet winters followed by long, dry summers. That puts it in a class of plants on the tough end of the care spectrum with gazania, gladiola, kniphofia, pelargonium, aloe and agapanthus.

This tiny blue bloomer is named after Belgian surgeon Matthaeus de L’Obel. In 1570, it was not uncommon for people who practiced medicine to botanize on the side. Who knows what they could find — the next new cure for the plague, perhaps?

But L’Obel didn’t actually trample through the African bush and discover lobelia himself. The genus was named in his honor, probably for the perennial form, since the tiny blue annual wasn’t plucked from the wilds until 1752.

It is the annual, not the perennial, that has taken a leading role in the garden industry. With good reason. It’s cheap, it is abundant, and it is a blue you will rarely find in other plants.

Beware though, when summer time arrives, the plants will become dormant, much like petunias, said Lily Doniaz, certified garden representative at Valley Garden Center in McAllen. At the right time, however, lobelias can also be used for ground cover or hanging baskets where they can cascade beautifully, she said.

“Year-round it is probably one of the most popular plants we sell,” said Bud Bergquist from Greenthumb Nursery in Lake Forest, Calif. “Our best-seller (has) to be Crystal Palace with deep blue petals and a white throat,” Bergquist said. “Blue Moon is a lighter pastel blue that flies out of the store. And white always remains popular.”

My favorite? Cambridge Blue with powder-blue flowers on green leaves. Lobelia looks best planted where it can spill.

These plants are fairly low maintenance but do well when mixed with other plants, Waugh said. They can be planted around the outside of pots with hot pink geraniums, Red Wax begonias, even red petunias.

Care: Provide full sun for best blooms.

Don’t feed lobelia too much. Even though it looks lush, it is a tough little plant that likes living on the lean side. A light liquid feed will help the plant fill in faster. Gro-Power is a good organic choice for garden beds. Others prefer Baccto.

Provide sharp drainage, especially in clay soils. Use cactus mix in pots or plant it between rocks or in sandy spots in the ground.

Prune. Lobelia is a tad frost tender in cold winters, but bounces back easily in spring after shearing. In early summer when the plant gets leggy, you can shear it again for another round of bloom. Don’t overwater. This little spiller thrives on the dry side. Like other Mediterranean plants, lobelia will rot away with too much water during hot summer weather. Try cutting them to the ground like perennials in the fall — when the plants are bloomed out — instead of pulling them out with other annuals. With any luck, they will come back the following spring.

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Sources: Annuals for Every Purpose by Larry Hodgson (Rodale); Sunset Western Garden Guide; The Principles of Gardening by Hugh Johnson (Simon & Schuster).

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Monitor reporter Miriam Ramirez contributed to this report.