Why Wont My Lobelia Flower. The three types of pruning that benefit lobelia plants are removing spent flowers pinching and cutting back. Keep an eye on the weather.
Cardinal lobelia is found in ponds and wetlands. Keep an eye on the weather. If the soil is moist allow it to dry some between waterings but make sure that it doesnt become too dry which can lead to browning.
Other common causes include watering fertilizer or temperature problems or an aging or root-bound plant.
The ones in flower in the garden centres have been forced and will not last as long as seedlings grown slow and colder. And right away I discovered there is a mosaic virus like the one that attacks cucumbersand the symptoms smatch mine pretty closely. Often grown as container and edging plants they can have bushy or trailing habits. 08032020 If the dehydration is too severe the plant may die.