Today gardeners and writers of nursery catalogs use the word bulbs for many plants that are not, strictly speaking, bulbs

Today gardeners and writers of nursery catalogs use the word bulbs for many plants that are not, strictly speaking, bulbs. The term has come to include plants with a distinct underground structure that enables them to be lifted out of the ground, stored (and even shipped), and then planted again in the ground to produce foliage and flow­ers. In most cases lifting takes place during the resting stage of the plant. (Why such resting stages occur is discussed in some detail on pages 47—48.) There are always exceptions. Certain plants generally classed as bulbs are evergreen, and while the greater number of them are plants that prefer warmer climes, such as Clivia, Agapan­thus and certain Hemerocallis, they have the attri­butes of being able to be lifted and transported, and have rootstocks or swollen stems that store food. It is this adaptation, the storing of food in stems, modified leaves or roots, that more accu­rately describes the broad sense of accepted use of the collective noun bulb. Just which forms are taken by various plants, and why, is worth look­ing at.

 

Plants develop rootstocks containing stored food and growth buds for both shoots and flow­ers, in order for them to survive periods in their native habitats when conditions are not suitable for continued growth. Overcoming that check to their growth caused by cold or drought, lack of moisture or searing heat, requires them to adapt their structure to withstand such adverse condi­tions, and at the same time, retain the ability to grow again when conditions are favorable. They become dormant during that unsuitable growing time.

 

Burying themselves deep into the soil, form­ing a hard shell to protect the stored food, adapting their leaves, roots or stems to endure adverse conditions—these are qualities shared by those plants we group under the word bullb. The period of time for which bulbs can remain dormant var­ies. Anemone coronaria, which forms a tuber (but is most commonly called a corm — it is often very difficult to distinguish between a corm and a tuber) can easily be stored for two years or even longer. On the other hand, a Lilium bulb, being composed of fleshy scales that are modified leaves, will lose turgidity and shrivel unless stored in cool temperatures and surrounded by material that prevents, to a large degree, the loss of moisture. Properly stored, it can be kept for 12 months, and no longer. Corms and hard tubers (a potato is a soft tuber) can be stored for longer periods than a fleshy bulb (such as an onion) or a rhizome (such as the bearded iris), yet all of these would be able to withstand adverse dry conditions better than such fleshy plants as the Clivia.

 

It is important to understand these differ­ences, which can be appreciated by just looking at and handling the various plants. Such knowl­edge enables gardeners to provide those condi­tions best suited for overwintering tender bulbs in colder climates. An Anemone can be kept dry. A lily cannot, but should be kept moist or pre­vented from losing moisture. Even as beginners we can, by observation and the application of common sense, begin to understand the needs of the plants. They are, in effect, quite logical.

 

Before considering in greater detail the dif­ferences between the various types of under­ground storage organs developed by the various plants in the broad grouping of bulbs, let’s look at some unusual adaptations of plants.

 

In certain parts of the world, particularly in grasslands, there is danger of fire during dry seasons. Fire sweeping through such areas is a natural event, and can even be welcome. In fact, certain shrubs need fire before they release seeds, or the seeds need fire to help break the hard coat that protects the viability of the seed.

 

In southern Africa there are many species of Pe/argonium. Among the popular garden plants we grow in our summer gardens are Mar­tha Washington geraniums and zonal geraniums, both members of the genus Pelargonium. While they grow in the wild close to the coast where fire is not common, other species of Pe/argonium grow in grassland where fires are common. They have developed the ability to form tubers, some­times just below, sometimes at or just above the surface of the ground. Fires sweeping through the area may destroy the shoots, but the tubers are not damaged. When the fires have passed, new growth emerges.

 

Other plants take advantage of fire to sur­vive, and afterward find themselves in an area freed—for a time—from competitors for available nutrients. If you walk over an area of the veldt in South Africa that has been scorched by fire, you will be amazed at how many small bulbous plants seem to pop up and enjoy the recently cleared areas. Without fire they remain dormant, or produce just a few leaves in order to maintain themselves, but after the fires have passed, they come into their rightful glory. They have sur­vived when other competing plants have suf­fered; these other plants have to start again from seed, while the bulbous plants, with established roots and food supplies, can and do take advan­tage of the situation to flower and seed. That seed will germinate and small bulbs will be formed, but they will wait to flower until the competition has again been reduced to ashes, and the cycle repeats.

 

But why should such fleshy-stemmed plants as Clivia and Agapanthus produce their fleshy stems? One might think they do so to provide a reservoir of moisture to take them through peri­ods of drought. In fact, Clivia grow in the shade of trees, not in the open sun. The trees consume moisture from the soil, and thus when moisture is in short supply, the clivias survive by using the moisture stored in their fleshy stems.

 

Agapanthus, on the other hand, grow in full sun, and while they don’t compete with other plants for moisture, they live in areas where the amount of moisture available in summer is lim­ited. When water is scarce, they can draw on their reserves. Why does one grow in the shade and the other in sun? I don’t know the answer to that, but I can tell you that Clivia has broader leaves by far than Agapanthus, following the gen­eral, and logical, rule that shade-loving plants often have broader and larger leaves than those of plants growing in full sun. With larger leaves to catch or absorb as much light as possible, they are adapted to their preferred locations.

 

 

TRUE BULBS

A true bulb consists of leaves modified for stor­age and a stem compressed into a flattened plate. The leaves are attached to the plate. From the plate, roots are produced. Attached to the plate on the upper side, and surrounded by the modi­fied leaves, is a bud containing the immature fo­liage and those cells that will develop into the flowers. This bud is the entire growth of the coming season, compressed into a very small area. In some bulbs the embryonic flowers are formed the previous season, as is the case with hyacinths. In others, the stem arising from this bud will produce foliage and buds at the apex; true lilies are examples of this.

 

Some true bulbs have modified leaves that are closely wrapped around each other, the outer leaves turning color and protecting the inner ones. An example of this type of bulb is the onion, with an outer “skin” (leaves) that becomes dry. Another example is the tulip. (If you cut through an onion, from side to side, you will eas­ily be able to see the “rings” which, if peeled off, can be seen to have veins, exactly like those of leaves. This is not the case with tulips.) Other true bulbs are made up of fleshy scales, and given good conditions these remain turgid and contribute to the strength of the bulb. True lilies are good examples of this type of bulb.

 

How can a gardener profit from such knowledge? When purchasing tulips, you now know that whether the bulbs do or don’t have an outer skin isn’t of great importance. (Except that, if tulip bulbs are offered for sale with the tunics in place, you can be sure that handling has not been rough, and that unseen bruises are not as likely to be present. Bruising can cause rotting.) If, on the other hand, you see lilies with dried outer scales (modified leaves), you know they have not been kept under optimum condi­tions and the bulbs have, to a certain degree, suffered. If many scales are dried, it is not a good idea to purchase that bulb. If the home gardener is storing tulips, it isn’t necessary to keep them moist, but lilies should be prevented from losing moisture. In our homes we commonly store on­ions, and no harm comes to them, even if they are stored for a fairly long period; the “skin” holds moisture in. Lilium bulbs, not having such a skin, will lose moisture more readily.

 

The most important part of a true bulb is the basal plate. It is from this that the roots are produced, and the leaves and future flowers and stem also are attached to it. If the basal plate is damaged, then obviously the ability of the bulb to perform is impaired. Check for damage when purchasing bulbs and when you lift and store them. If the plate is badly damaged, it is best to discard the bulb, as such damage will provide an entry point for disease. A sound bulb will be plump and firm to the touch with the basal plate undamaged. True bulbs are generally oval, pear-shaped or rounded.

 

 

CORMS

A corm is a stem that is swollen and otherwise modified for storage. Generally, the underground portions of the stem are so modified, and take on a rounded shape, concave on the bottom and flattened on top. Frequently this storage portion has a brown skin called a tunic—the basis of the stem leaves. In some cases, notably the crocus, the skin (tunic) has a meshlike or woven appear­ance, which can be an aid in the identification of various species.

 

Unlike “true bulbs,” corms are solid. The roots are produced from the bottom, the shoots from the top. The food for the developing shoots and for the roots is contained in the corm, and by the end of the growing season the original corm is shriveled, and a new corm is usually found on top of the old. Clustered around the new corm will be little cormels, and often, as in the case of Gladiolus, the cormels are very numerous.

 

When you lift a corm at the end of the sea­son, remove the old corm and store just the newly formed young corm. Unless you are going to propagate the cormels and grow them on to flowering size, discard them. It takes some two to four years to raise cormels to flowering size. They should be sown in drills, as peas and beans are sown, but only 1 inch deep. Grow them on for one year, and lift and store over winter. The following spring, sow them again, a little deeper this time. By the end of the second season, they should have reached flowering size and can be planted where you want them to flower. If you live in a warmer climate and leave the corms of gladiolus, for example, in the ground, you will find the cormels will send up shoots that look for all the world like grass. If they are not wanted, just hoe them off.

 

 

TUBERS

A tuber is a swollen underground stem or root, but not the base of the stem, as is a corm. It is usually fleshy, rounded and covered with scaly leaves often invisible to the naked eye and con­centrated toward the top of the tuber. In the axils (where scales are joined to the tuber) of these scales, eyes (buds) develop, and it is from these eyes that the stems and flowers are produced. There are two basic types of tubers, those formed from the stem, and those formed from roots. The dahlia has tuberous roots on which there are no eyes; the eyes are found at the base of the stem. It is essential that dahlia tubers each have a piece of the old stem with eyes, as the tubers them­selves will not produce any new growth, having no buds.

 

An example of a root-forming tuber is the potato, in which the eyes are quite evident. Most people know that if you leave potatoes in storage for a long time, shoots will emerge from those eyes. A more attractive tuber is the cyclamen, but there is some confusion, as many gardeners call the tubers of cyclamen “corms,” however in­correct this may be. Roots can emerge from al­most any part of a tuber, but the majority will be from the underside, which is generally rounded, while the shoots emerge from the upper side, which is often concave. In the case of the potato, however, roots arise from the base of the new stems.

 

That there is a difference between top and bottom is a help when planting cyclamen, but when planting Anemone coronaria for example, it does not seem to matter how you plant them —which is fortunate as it is almost impossible to tell top from bottom!

 

 

RHIZOMES

A rhizome is a swollen underground stem that has apices (tips) from which shoots emerge. There is generally only one apex that will pro­duce growth at the time of purchase, but after a season or two of growth, the parent rhizome will start to produce side shoots at the end of which shoots will emerge. The roots are produced on the underside of the rhizome. If you cut into a rhizome you’ll see it is solid, just like a corm or tuber, but the difference between a rhizome and a corm is that only the ends of a rhizome produce shoots. In the case of corms and tubers, growth is from the top. The rhizomes of bearded iris grow with their tops exposed to the sun. While certain plants have rhizomatous roots and spread by producing such, these roots are not swollen and do not act as storage units. Only those roots that are swollen and act as storage units are included in the broad use of the word bulb.

 

 

WHERE DO BULBS COME FROM?

I doubt if there is a country in the entire world that does not have a bulbous plant growing wild somewhere within its boundaries. Of the some 250 genera that contain bulbous species, 97 of them are found in South Africa. Some of them are not well known, such as the genera Depidax, Gethyllis, Hexaglottis and Walleria, but others are well known to gardeners. Among these are Agapanthus, so widely grown in the warmer parts of the United States; Amaryllis; Clivia, one of the finest bulbs for winter color in warmer climes; the glorious Freesia; the popular florist’s flower, Gloriosa; the pretty Nerine; the great container plant Lachenalia; and the tough Arum lily correctly called Zantedeschia, now found growing wild in many parts of the world, and indeed often regarded as a weed in parts of California.

 

The beauty of many South African species has yet to be discovered by American gardeners. Some watsonias are known, but more should be grown, and who knows just what new colors will be forthcoming when the full range of Gladiolus that grow wild in Southern Africa are more ex­tensively used in breeding programs? The angel’s fishing rod, Dierania, are worthy garden plants, found in a few gardens, but so very worthwhile they should be grown more extensively. Surely when the unusual colors of such plants as Ferra­ria become known, gardeners will demand they be available commercially. I think it fair to say that we have but scratched the surface of the bulbous plants worthy of commercial introduc­tion. Goodness only knows what marvels of color and form can be created by devoted hybridizers of such genera.

 

We often think of plants as coming from countries with which we associate them strongly, but often those places are not their true homes. The most popular of bulbs, the tulip, did not originate in Holland but in Afghanistan, China, Crete, Greece, Iran, Turkestan, Turkey and other areas around the Mediterranean. Many of our lilies come to us from China, Japan and Korea, and from species that grow wild in these lands, we have the forebearers of many of our lovely hybrids. True, there are many lovely spe­cies native to North America, but these are not as popular as the many hybrids, the progeny of bulbs from other lands.

 

Some bulbs are found in many different parts of the northern hemisphere, the iris being a good example. Irises are not found in the southern hemisphere. However, the family of the iris is well represented by the genera Dietes and Moraea, found below but not above the equator. Snowdrops and snowflakes, Galanthus and Leucojum, are native to Europe, while North America is home to the splendid Trillium and the Calochortus, commonly known as the Mariposa lily.

 

With such worldwide distribution it is to be expected that there is a bulbous plant for every garden, no matter what the soil type or the cli­mate. Bulbs are versatile, many having built-in life cycles that enable them to survive and thrive where other plants can not.

 

In our gardens today, we could—if we had the room—grow several hundred different culti­vars of tulip. Yet only a half century ago the exact bloodlines of tulips were unknown. Herein lies a tale. For many years tulips were appreci­ated in their native lands. Prior to the thirteenth century, Omar Khayyam mentioned them in his writing. The first Mogul ruler of India, Moham­med Barbur, collected them in the early part of the sixteenth century, and Pierre Belon, a French naturalist traveling at that time in Turkey, men­tions “red lilies,” no doubt a reference to tulips.

 

In 1529, Suleiman the Magnificent was lay­ing siege to Vienna. The then-Emperor of Aus­tria, Ferdinand I, sent his emissary Augier Ghislain de Busbecq to Constantinople (now Is­tanbul) to seek peace terms. There the emissary saw fields of flowers, bought some bulbs and shipped them back to Austria, where they came under the care of Carolus Clusius, the court bot­anist. A little while later, Clusius left Vienna to take an appointment as professor of botany in Leiden, Holland, and he took his bulbs with him. For this reason alone the tulip industry for many years was centered around Leiden.

 

During the sixteenth century, the growing of rare and unusual plants was much in vogue in Great Britain. The wealthy vied with each other, not only for the largest houses and collections of art, the most lavish stables and other material objects, but also tried to outdo each other with the magnificence of their plant collections. Plants were imported from all over the world, and among them were many bulbous plants.

 

In his Paradisi in Sole Paradiius Terrestris (1629), John Parkinson mentions daffodils, fritillar­ias, saffron flowers, lilies, tulips and many other bulbs. Such was the interest and demand for new and unusual plants that seed and bulbs were often transported in diplomatic pouches. Obviously seed was easy to carry, and bulbs, more easily trans­ported than shrubs or trees, were also natural choices for such shipments. During the seventeenth century, many bulbous plants still widely cultivated today were introduced into Great Britain, among them Agapanthus africanus, from South Africa, Sprekelia formosissima, from Mexico, and Hippeas­trum reticulatum, from Brazil.

 

During the eighteenth century, the number of bulbous plants introduced into Great Britain was astonishing, and included such well-known plants as Zantedeschia aethiopica, the Arum or calla lily from South Africa; Crinum asiaticum, from tropical Asia; Alstroemeria pelegrina, from Chile; Trillium erectum sessile, from North America; Tritonia securigera, from South Africa; Eremurus spectabilis, from Siberia; and Dahlia variabilis, from Mexico. Bulbous plants were not only in demand but were introduced into culti­vation from the four corners of the globe. Through­out the nineteenth century, bulbous plants from the Himalayas, Tibet, Peru, Syria and Uruguay were introduced, and by the early part of this century, there were few genera of bulbous plants not in cultivation. It is indeed unusual to find a new genus of plants, but new species are still being found. (Still, it must be admitted that it is rare to discover a “new” species of outstanding beauty.) Today, we are dependent on the work of hybridizers for new, beautiful cultivars. But such is the gene bank that has been established over centuries that, for the foreseeable future, hybridizers have an almost un­limited number of species with which to formulate lines of breeding.

 

It is entertaining to read the accounts of the many plant hunters and explorers who roamed the world on their quests. When one realizes the rather primitive modes of transportation, the length of time it took to reach the areas where many of our bulbous plants are at home, one has to admire the courage of these people. Their adventures were many, the hardships endured were almost beyond belief, and yet such was their determination that they willingly went back time and time again to collect new species. Their rewards were not great (many re­ceived little monetary reward), but their prestige and the admiration of their fellow plant lovers —who were not as adventuresome — could not have been greater.

 

Yet these men were humble. It was only after I had known Harold Comber (1897—1969) for a number of years, for example, that he would recount for me his adventures. He ex­plored vast areas of Tasmania, traveling on horseback, carrying cumbersome plate cameras with photographic plates that were heavy and easily broken, nothing so light and easy to use as rolls of film. He and his exploration party had to shoot their food if they wanted meat, and spent weeks and often months on their journeys. As the time for seed gathering is fall, the weather was not always pleasant and balmy.

 

Plant hunters must have a tremendous knowl­edge of plants. The explorers who have brought us so much knew the characteristics of the various families, and proper identification of the various species they came across was essential to their work. How crushing it would be to bring back specimens of plants already in cultivation! Because the number of plants that could be handled physi­cally on an expedition was limited, it was critical to spend effort on only new, unknown plants.

 

Plant hunters had to be knowledgeable about the needs of the species introduced so they could advise how best to cultivate them. It was important that precise records be kept of the lati­tude and longitude of where each specimen was found—an added chore, especially as maps of many regions explored did not exist. Many men who were sent to remote regions of the world as missionaries had an interest in plants. Two we must thank for many introductions from China —among them the genus Nomocharis —were Pere Jean Marie Delavay (1838—1895) and Armand David (1826—1900). Many plants have been named in their honor. Their writings inspired others to hunt for plants in China, a country that rightly deserves the name “Mother of Gardens,” as many fine plants, shrubs, trees and bulbous species were found there.

 

Information on how to grow the various new plants introduced was often sketchy, to say the least, despite often copious notes by those who discovered them. The lovely Peruvian lilies, Alstroemeria, were brought back from South America but for some reason didn’t survive in cultivation. Harold Comber was sent out in 1929 to rediscover this lovely genus. It is thanks to his efforts that this plant was reintroduced, and flo­rists the world over owe Harold a deep debt of gratitude, as do all of us who admire these plants in our gardens or arrangements.