Cardinal flower, Lobelia cardinalis
 
Striking red flowers are a favourite of humans and hummingbirds alike.
Cardinal flowers are a showstopper, with their bright red spikes blooming from July to September. The plant has a flat basal rosette with a 90cm to 1.20 m tall stalk showing off the flowers.

Ecology:
Scarlet red signals to the ruby-throated hummingbirds that the flowers contain a lot of nectar. The very long tubular flower shape is perfectly formed so that when the hummingbird's long beak reaches the nectar, the flower's anther can powder the little bird's forehead with pollen. What a beautiful example of co-evolution. 
Cardinal flowers are larval host plants for different species of moths.
Birds eat their tiny seeds.
 
Growing conditions:
In the wild, cardinal flowers occur next to streams, ditches, and marshes, where they thrive in moist to wet conditions in sunny to partially shaded locations. However, they can do well in regular garden settings if we provide watering during the driest times.   
Since lobelias are short-lived perennials, the plants will produce many seeds to ensure they can replenish the older plants. Therefore, it is a good idea not to mulch around lobelias so they can self-seed, and the seeds will have good contact with the soil. This will enable the seeds to sprout and replace older generations quickly.