Fertilizing:

Perennial varieties can usually get by with a yearly application of fertilizer or compost in the spring. For annuals, fertilize more frequently or apply a continuous-release fertilizer for flowering plants to sustain them throughout the growing season.

Pruning and deadheading:

Most annual lobelias are self-cleaning, so you don’t need to deadhead them. If blooming slows during the heat of summer, the best way to revive them is to cut them back by as much as one-half to two-thirds, followed by regular watering. This radical pruning will regenerate new growth, and by the time the cooler weather of fall arrives, your plants should be in full bloom again. You can also pinch back plants at any time if you prefer bushier growth.

Avoid pruning back or deadheading cardinal flower and other perennials if you want them to reseed naturally.

Amazing Campanula flowers for your garden – the “groom” and the “bride”

Propagating:

Perennials tend to be short-lived, but the plants are easy to propagate by dividing them in the spring or fall or by taking stem cuttings after your plants finish flowering. Unless you plan to let your plants self-sow, divide them every two or three years to extend their lifespan.

Winter protection:

If perennials are covered with heavy mulch over the winter, the roots can rot, especially in warmer southern climates. If you typically mulch your perennial beds to prevent frost heaving and root damage, use a light layer of mulch that won’t completely cover the basal leaves.