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Geohyte is the term for a plant with an underground sotage structure: bulb (tulip, daffodil), corm (freesia, gladiolus), rhizome (iris), tuber (begonia, potato), ant tuerous root (ranunculus, dahlia).

It's not that crucial to know which kind of root you are buying, but there arae some differences in how they grow. Bulbs and tubers can grow bigger and bigger, blooming year after year, and often muliplying readily. Corms usually get used up as the plant grows and blooms, so you need reasonably rich, well-drained soil for them to produce new corms and continue for future years. Rhizomes grow outward at ground level, so we don't plant them as deep as the others and we give them room to spread. Rhizomes and tubers have multiple growing points, making them very easy to propagate and share with your friends: just cut them up.

For convenience, we call all of these "bulbs" and fall is the time to plant the flower bulbs that bloom in spring. Summer-blooming "bulbs" such as gladiolus and dahlias are planted in spring.

When we know where a plant comes from we can surmise its cultural requirements. Although we associate many bolba with Holland (where 65% of the world's flower bulbs are grown – 2002 figures), their ancestral geographic origins belie this heritage.

Take tulips. Hybrids such as the Darwin tulips prefer cold winters due to years of breeding for that. But tulips originally came to the Dutch from the Ottoman empire in the 16^th century. Tulip species originated along the 40^th latitude from western China to Turkey, spreading out to Afghanistan, Iraq, and Iran, and then west to the Mediterranean. So while the Dutch hybrids tend to bloom only for a year or so in our gardens, species such as T. clusiana, from warmer areas, will multiply and spread here.

Bulbs appear to be primarily an adaptation to aridity, especially dry summers. In fact, some of the largest bulb-like things in nature are from desert or chaparral areas. The Manroot, a cucumber relative native to Southern California, develops tubers that can reach 200 lbs! The plant grows very rapidly with the sparse winter rain, then lies dormant for months. Giant White Squill, a native of Crete, has bulbs that average 5 – 6 lbs. each.

Protection from winter cold is an added bonus of bulb formation, and a few require more winter chilling than we get in order to break dormancy properly: lily-of-the-valley and snowdrops are examples. But those are the exceptions. Most bulbs grow fine here.

Geophyte geography: where is Asia minor, anyway?

Researching the origins of bulbs, I kept coming up with "Asia minor" for many species. Anemones and Ranunculus. Hyacinths and some Tulips. What is this region that is the source of so many of our favorites? I did well in high school geography, but that was decades ago. Nobody I asked could place it ("isn't that, like, west of China?").

Also known as Anatolia, Asia Minor is basically the Asian portion of modern Turkey (about 4% of Turkey is in Europe). Geographically it includes quite a range: the Mediterranean coast, where subtropical fruits such as citrus and figs are grown; high, dry plateaus, and east to even higher mountain ranges, including Mt. Ararat (nearly 17,000 ft.) at the border with Iran at the furthest east end of the region.

Mild-winter coasts, high mountains, with fertile valleys in between? Sounds a lot like Northern California. No wonder Ranunculus flourish for us! In fact, we are able to grow most bulb species that originate from cold climates, as well as those from mild-winter areas of both hemispheres. Two other major sources of bulbs for California gardens are the mild-winter, dry-summer regions of the Mediterranean and South Africa.

From the Mediterranean we get Crocus species, colchicums, cyclamen, grape hyacinths, several species of Narcissus, Scillas, and several more species of tulips. Giant hybrid crocus prefer a colder-winter area, but the species types do great here. Cyclamen hybrids are among our most popular winter-blooming flowers, perfectly hardy outdoors even on frosty nights. Most people don't even know they are a bulb, but you can save them from season to season. Just keep them dry during the summer.

The powerfully fragrant Narcissus papyraceus which we call Paperwhites, are from the Mediterranean. They sprout early, often blooming before Christmas, and spread rapidly in the garden – but in bulb catalogues from east-coast firms you'll find them consigned to the back pages as "indoor bulbs". Ah, the pleasure of living in balmy California: Mediterranean geophytes thrive here.

The Cape of South Africa is another region of winter rains, dry summers, and mild temperatures similar to California. The Cape boasts over 1500 species of geophytes, an amazing diversity: our ubiquitous Agapanthus (Lily-of-the-Nile, a tuberous root), old favorites such as freesia, gladiolus, and calla lily, and lesser-known choices such as Crocosmia, Ixia, Sparaxis, and Watsonia. All of these latter bloom and multiply freely here, yet are too tender for gardeners in colder areas.

Sorting them: Tulips and Daffodils

Tulips
Tracing the origins and relationships of these older bulb types and giving them proper names is complicated. Why? Because gardeners had been growing, propagating, and breeding them for a couple of hundred years before the whole science of plant relationships (taxonomy) and system of naming (botanical nomenclature) was invented. DNA research is revealing some interesting relationships, but many are complex hybrids.

In this situation, horticultural taxonomists will sort cultivars into groups based on similarity of flower form or bloom period. In the case of tulips there are over 2000 cultivars, in 15 recognized categories such as Single Early, Darwin Hybrid, Lily-flowered, etc. Hybrids known to be mostly from a particular species bear that name: the Fosteriana tulips, also known as Emperors, have at least some T. fosterana parentage (they also happen to be good choices here).

By the way, we can grow the old-fashioned, long-stem tulips here. Just don't plant them too early. Wait until the soil has cooled (Nov. – Jan.), and plan on planting new ones each year. That said, I have seen tulips repeat, sometimes for years, when they are planted where they get little or no summer watering. Follow the same instructions for hyacinths: plant Nov. – Jan., and if you want them to repeat put them where they will be dry in summer.

Tulips come in nearly every color, including black, as well as striped, fringed, and freakish forms. Hyacinths come in strong primary colors, including true blue.

Daffodils and narcissus
come in yellow, white, and pink. Although some species of Narcissus (the genus which includes daffodils) grow wild in Europe, their great popularity as garden plants came later: in the late 19^th century and early 20^th century hundreds of hybrids were developed using species found in Asia and the Mediterranean.

Today there are over 3000 cultivars, sorted into groups called divisions. Because the parentage is somewhat better known, the divisions other than the biggest-flowered types reflect the species they resemble.

* If you want the familiar big-flowered ones, plant Trumpet daffodils. They'll repeat year after year, but usually don't increase.

* If you like novelty flowers, try the Split-cup and Double forms. My experience is they don't return as well in future years.

* If you want big, showy flowers on plants that multiply, plant Large-cup and Small-cup types, and the dwarf Trumpets.

* If you want super-fragrant blooms on plants that will multiply even more freely, plant from among the other divisions: Cyclamineus, Tazetta, Triandrus. For elegant flowers, try the tall, late-blooming Poeticus narcissus.

* For cute little plants that multiply exuberantly, nearly all extra fragrant, plant some of the species types.N. canaliculatus (6" tall!) and N. jonquilla simplex (12") can be crowded in a pot and brought indoors in bloom to perfume the whole house.

Whichever you choose, all daffodils and narcissus are easy to grow and most will give years of bloom.

I counted over 100 species of flowering bulbs that grow readily in our gardens in the Sacramento Valley! Geophytophiliacs know that I've only scratched the surface here. The bulb is truly the gardener's friend: easy to plant, and productive for many years.