Summer bulbs require no chill | Tony Tomeo

Unlike spring bulbs that like to be in the garden early enough to benefit from winter chill, summer bulbs do not benefit from chill. Some actually dislike it.

Also unlike spring bulbs, very few summer bulbs, or late bulbs, are actually bulbs. Almost all are rhizomes, tubers, tuberous roots, corms or other types of dormant but reliably perennial storage structures.

Summer bulbs do not grow through early winter to bloom later in winter or early in spring like spring bulbs do. They instead grow through late winter and early spring to bloom for late spring or summer.

A few bloom for autumn. Several are more reliably perennial than the majority of spring bulbs. However, some bloom splendidly only for their first seasons.

Gladiolus is one of the most popular summer bulbs, but like many spring bulbs, it blooms only once annually, and is not reliably perennial. Planting in phases every two weeks or so through their planting season prolongs bloom. However, most corms do not survive to bloom for a second season.

Those that do will synchronize for their subsequent blooms.

Dahlia blooms for a longer season from the middle of summer until the middle of autumn. Also, it is more reliably perennial. Tubers remain dormant through winter after stems and foliage die back. They generate new stems and foliage through warming spring weather.

Overgrown or crowded tubers propagate efficiently and easily by division while dormant.

Summer bulbs are not quite as diverse as spring bulbs, but some types are too vigorous for much diversity. A few rhizomes of canna can become overwhelming within a year.

Old fashioned white calla forms broad colonies that might exclude other perennials.

Smaller and more colorful modern cultivars are fortunately docile. Crocosmia might get invasive, and is difficult to mitigate.

Flame vine

Like so many popular spring bulbs, flame vine, Pyrostegia venusta, may not delay bloom until spring as it should. Within the warmly sunny situations that it prefers, it is more likely to bloom during winter.

It may wait until the end of winter or even the beginning of spring only where winter weather is cooler. Bloom is already finishing where winters are milder.

Bloom is spectacular, particularly while not much else blooms so copiously. It is about as profuse as bougainvillea bloom, but earlier. It is about as vibrant orange as poppy bloom, but earlier. With warmth, sunlight and regular watering, flame vine performs very reliably.

Perhaps it should not be as uncommon as it is. Yellow blooming flame vine is quite rare.

Although a bit tamer than related red trumpet vine and royal trumpet vine, flame vine may be uncommon partly because it is so vigorous. If pruned to the ground after bloom, it can reach second story eaves to bloom there for the next season.

It can grow absurdly high if it grows into trees. Its evergreen foliar tendrils can cling to and damage painted surfaces.