The plants we refer to as growing from summer bulbs are similar to those that grow from spring blooming bulbs with one exception: the summer bloomers are mainly tropical or sub-tropical in origin so their bulbs are not winter hardy.
We plant these bulbs in the spring for summer flowers, and like the spring blooming bulbs, there are a number of different types. They include the true bulbs, but also tubers, rhizomes and corms. They are more labor intensive, as they have to be dug and stored each fall to over-winter indoors. However, summer blooming bulbs add immeasurably to the diversity of the summer garden, and each are showy and valuable in their own way.
The most common are gladioli, tuberous begonias and dahlias. However, the peacock orchid (Gladiolus callianthus), which has white flowers with a purple throat, is also garden worthy. And the Mexican shell flower (Tigridia pavonia), sometimes called tiger flower, has iris-shaped flowers with markings in an array of bright colors.
Summer hyacinth (Galtonia candicans) is fragrant and tall and white so combines well with flowers of any other color. Who can resist the blue of Agapanthus, commonly known as the Lily of the Nile? These beauties are favorites in cities such as Cape Town, Sydney and Los Angeles—cities with similar climates, and more importantly for the Agapanthus, mild winters.
However, those of us who have cold winters can grow them too, but it takes more effort. We can grow them in big pots that we drag inside in the winter, or we can dig the bulbs and store them indoors and replant them each spring.
So it is not quite so easy, but then some things are worth the effort, especially if we grew up with the plants in a milder climate or just love that blue.