Summery Bulbs After Spring Bulbs

Many summery bulbs bloom only once.

Spring bulbs prefer an earlier start, and several appreciate a bit of winter chill. Summery bulbs, or summer bulbs or late bulbs, prefer a later start to avoid such chill. Most tolerate minor frost, but none benefit from it. If too early, some can start to decay while waiting for warmer weather. Some can grow prematurely, and perhaps incur damage from late frost.

Summery bulbs are in season now because they take a bit of time to grow. The potential for frost should be minimal as their foliage emerges above their soil. Once established in their first seasons, many could stay in their gardens indefinitely. They should be resilient to minor frost by their second seasons. Most that incur damage should recover efficiently.

However, many summery bulbs are not reliably perennial. Cannas and gingers can grow aggressively enough to become invasive. Gladiolus, though, may bloom half as much for subsequent seasons until none remain. Some who like to grow dahlias prefer to dig and store the tubers through winter. This is more likely to protect them from rot than from frost.

Incidentally, few summery bulbs are actually bulbs. Most are perennial rhizomes, corms, tubers or tuberous roots. Some, especially those that grow from tubers or tuberous roots, bloom longer. Those that grow from bulbs, corms and rhizomes mostly bloom only once. Succession planting prolongs their first bloom seasons, but they synchronize afterwards.

After their summer bloom seasons, most summery bulbs defoliate for a winter dormancy. This is actually why they are in season now. After all, winter dormancy is the best time for transplanting, division and thinning. Cannas and gingers could try to retain some foliage through winter. Cutting it all back might be easier than grooming it from new foliage later.

Dahlias might be the most popular of summery bulbs. Cannas and gingers are likely the second most common. Alliums and old fashioned tuberous begonias are becoming more popular. Tuberous begonias are not so easy to grow, though. Crocosmias are too easy to grow, and are invasive. Alocasias and colocasias provide colorful and boldly big leaves.

Summer Bulbs Require No Chill

Many bulbs are not actually bulbs.

Narcissus, including daffodil, started to bloom during all that earlier torrential rain. Those that bloomed after the rain stood up a bit better than those that started earlier. Crocus are stouter so are more resilient. Hyacinth are both relatively stouter and slightly later. While such spring bulbs contend with late wintry weather, it is about time to add summer bulbs.

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.

Gladiolus

Gladiolus are still just dormant corms.

Although they will not bloom until summer or autumn, gladiolus are in season now. Their corms, which are like bulbs, are now available from nurseries, and are ready for planting. Unlike earlier spring bulbs, they need no chill, and should not generate new foliage until warmer spring weather. Corms prefer to be at least four inches deep, in sunny situations. 

The most popular and common gladiolus, Gladiolus X hortulanus, are hybrids of several species. They bloom more impressively than their simpler parents, but are not as reliably perennial. Most corms bloom for only a single season, although some within each group may bloom for a second season or more. Blooms can get heavy enough to need staking. 

Bloom can be bright or pastel hues of any color except true blue, perhaps combined with another related color. Individual florets are not large, but they share their floral stalks with several similar florets that bloom upward from the bottom. Long and pointed leaves stand upright, flaring only slightly to the left and right. The tallest gladiolus can get six feet high.

Late Bulbs Require No Chill

Cannas grow after spring bulbs bloom.

Spring bulbs are making a comeback from their unceremonious internments last autumn. Some of the earlier sorts are visibly extending foliage above the surface of the soil. A few narcissus, daffodil and crocus are already blooming! Now it is time to plant late bulbs, or summer bulbs, which start to grow through warm spring weather, and bloom for summer.

Spring bulbs are generally the same as hardy bulbs of climates with cold winter weather. They are hardy to frost while dormant. Since chill is relatively mild locally, their hardiness is irrelevant. Conversely, some prefer more chill than they experience locally. Inadequate chill can compromise performance. Autumn planting maximizes their brief chill exposure. 

Late bulbs are completely different from spring bulbs. Not only do they not require chill to perform, but some dislike it. Many of the most popular late bulbs that can naturalize here succumb to frost elsewhere. Instead of early planting for chill, as spring bulbs prefer, late bulbs prefer late planting to avoid chill. Their foliage emerges after the last threat of frost.

However, although they do not need or even appreciate chill, most popular late bulbs are resilient to the minor chill of local climates. Once established, they simply die back to the ground in response to the first frost of autumn. They maintain dormancy through winter to regenerate for spring. Some repeat this process for years, since the soil does not freeze.

Not all late bulbs are actually bulbs. Most are corms, rhizomes, tubers, tuberous roots, or other bulb-like perennials. Some, such as dahlia and canna, bloom through an extensive season. Some, such as lily and gladiolus, bloom only once. Planting in phases for a few weeks prolongs their bloom. Of course, they will synchronize for any subsequent bloom.

Canna and common white calla are two of the most reliable late bulbs. Crocosmia is too reliable, and since it can be invasive, it is rarely available. Common gladioli and various lilies are spectacular in bloom, but not reliably perennial. Dahlia is a very rewarding and reasonably reliably perennial summer bulb. It is spectacularly variable in color, form and texture.