Lobelia Flower

Which Lobelia Flower Should You Grow In Your Garden?

The beautiful lobelia flower comes in hundreds of varieties, each one just as stunning as the other.  For most gardeners the vision that comes to mind is a display of tiny, vibrant blue flowers but they actually come in many other colors.  These flowers are grown all around the world in cool, hot, dry and wet conditions.



Lobelia Erinus

This annual flower is a favorite in the garden, used as edging along borders and walks.  Native to South Africa, they provide a spectacular display of blue and purple.  They can be grown in window boxes, pots or the garden and they typically reseed themselves in the fall.  This lobelia flower is easy to grow as long as you keep them from being in direct sun during hot summer months.  They blossom aggressively in cooler weather and partial shade.

Lobelia Cardinalis

Known as the cardinal flower, the lobelia cardinalis is a favorite by those wanting to attract butterflies and hummingbirds to their garden.  These scarlet flowers bloom mid-summer and are sure to outshine the rest of your garden.  These flowers thrive when planted near rivers, streams or in marshy or boggy areas.  They prefer mostly shade but will tolerate full sun for a small part of the day, providing it is not the afternoon sun.  This lobelia flower has a much longer tubular part than most other varieties.

Lobelia Siphilitica

These plants have a tremendous amount of blue flowers and lance-shaped leaves on an upright stalk.  The flowers are ideal to use as a border in a marshy spot or a woodland garden.  They do not at all appreciate heat or sun and should be offered a substantial amount of shade.

Lobelia Inflata

Also known as Indian tobacco, these flowers are grown primarily in wildflower gardens.  Naturally they prefer cultivated fields, meadows and pastures and unlike most other varieties, this lobelia flower actually will tolerate a fair amount of sun.  The plants take a good two years before they will flower but if provided proper growing conditions they will reseed themselves.  The flowers are white and tubular that bloom late in the summer.  The milky sap from the seed pods have been used as an herbal cure for various skin conditions.

Planting and Care

Seeds should be planted in small planters using garden soil approximately 10 weeks before the last spring frost.  You do not need to cover them up with any soil.  The light actually helps them to germinate and sprout.

When choosing a location in your garden, it should be a spot that receives no more than five hours of full sun per day, preferably with shade in the afternoon.  After the final spring frost, dig a hole not much larger than the roots.


Place the plant into the hole being careful not to bend the roots and fill the hole back up with its original soil.  Immediately water the plant to pack down any air pockets and pack the soil tight.  If you are planting more than one lobelia, they should be at least six inches apart from each other.

Aim to keep the soil moist at all times by watering three times per week.  When watering, be sure to saturate the soil completely.  The plant should be offered a 10-10-10 NPK balanced fertilizer once a year in the early spring.  This will encourage the flowers to bloom during the growing season.


Halfway through the growing season, these flowers should be pruned.  In the spring, they bloom profusely so to encourage an additional round of blooms, you should cut them back quite a bit mid-summer.

Unlike fruit trees or rose bushes, there is really no special care involved with pruning.  At the end of the season, they should be pruned down to the ground and then covered with mulch to protect the plants through the winter.