When Do Geraniums Flower?
Geraniums flower in spring and summer.
Generally speaking, geraniums that are planted soon after the last frost will begin to flower in the early spring.
Different Species Different Bloom Times
There are over 200 species of geranium, some requiring different care and having different bloom times. As an example the Martha Washington variety requires cooler temperatures and will not flower during the hot summer season. So this particular species will only flower in the spring and fall.
Potted geraniums will flower all year long if they are brought inside for the winter and kept in a warm, sunny location. They can be returned to outside containers and windowboxes as soon as the last frost has passed and the temperatures remain above 60°F.