Growing areas

The bulbous plants which can be grown indoors, are native to Mediterranean and (sub) tropical areas. The most import growing areas are South Africa, South America (especially Chile) and the southwestern states California and Oregon in the USA. The plants grow in general in the cooler, humid periods and are resting (dormant) during the warm, dry season. Another possibility is that they grow in the short period between these two periods, normally in spring, seldom in autumn. The climate described here can mainly be found in temperate areas and less frequently in savannah regions. These are the two most important regions for the distribution of bulbs.

South Africa
A comparison of all natural habitats for flowering plants shows that in South Africa the largest number of different flowering plants occur. The main distribution areas in this country are Northern Cape, Western Cape and Eastern Cape, especially the Cape Peninsula. The largest number of different bulbs, in particular true bulbs, can be found in these areas. The acreage of the Cape Peninsula is about 1,000 square km. On this restricted area more flowering plants, a.o. bulbous plants, grow than in the rest of South Africa together. To illustrate this from some genera is written down how many species grow in this part of South Africa, with between the bracts the number of species: Anthericum (15), Gethyllis (4), Gladiolus (20), Lachenalia (14), Moraea (16), Ornithogalum (10), Oxalis (32) en Watsonia (7).

The are some theories about this richness of flowering plants on the Cape Peninsula.

According to the first theory the Cape Peninsula has to be regarded as a seperate part of South Africa. In the north the Peninsula the, natural, border is formed by mountain chains and in het west, east and south by oceans. During the centuries a very specific flora has been developed under the influence of a stabile Mediterranean climate. This climate on its turn is caused by the warm and cold water flows of the Indian and Atlantic Ocean. This has resulted in an unique flora.

The second theory is the so called migration theory. According to this theory vegetation types have moved from the north to the south unther the influence of a slowly chancing climate. This process has been going on for decades. Various scientists have shown that plants on the Southern Hemipshere move slowly to the south. One on the most southern parst of Africa is the Cape Peninsula. Here ends the journey of the plants.

In the amount of bulbous plants Namaqualand comes second after the Cape Peninsula. Namaqualand is a semi desert area which is situated in the most north-western part of South Africa and in the southern part of Namibia. The South African part of Namaqualand is in the north bound by the Orange River and in the west by the Atlantic Ocean. There is no real border in the east. One can say that Namaqualand is that area where the climate is influenced by the Atlantic Ocean. Rain falls usually during the winter months, but it is, however, better to speak of irregular rain fall with a peak in the winter months, annually 50-150 mm (The Netherlands: 750 mm). There are also years when it doesn't rain at all. The plants in Namaqualand are adapted to the drought. A lot of succelents grow here, especially from the Mesembryanthemaceae. Bulbous plants that grow here are, e.g., the genera Bulbine, Lachenalia, Massonia, Ornithogalum, Oxalis and Ornithogalum. The bulbs have in general small leaves and are mostly round in diameter. The surface is sometimes covered by small hairs or a waxy layer. You could say that the leaves are succulent. Remarkable is that most bulbs from Namaqualand flower before the leaves are formed or after the leaved have died.

Chile is situated on the eastern coast of South America in the Southern Hemisphere between the latitudes 18 šN and 55 šS. The country is bound between the Pacific in the west and the Andes mountains in the east. Chile is, from north to south, 3,500 km long, and from east to west 300 km wide. The country can be divided into different climatic zones due to the geographical situation.

The central part of Chile with its winter rainfall, is the most interesting part when it is concerns bulbous plants. The area around the capital Santiago and the nearby lower slopes of the Andes are the most important areas for the distribution of bulbs in South America. The area comes second after South Africa in being the natural habitat of most well-known bulb families, in particular of the Amaryllidaceae. Well-known genera from Chile are Alstroemeria (Alstroemeriaceae), Habranthus, Hippeastrum, Rhodophiala, Phycella, Placeae (all Amaryllidaceae) and Leucocoryne (Alliaceae).

United States of America
The south-western states Oregon and California in the USA are another interesting growing area of bulbous plants. The climate in this are can be chararterized as a Mediterranean climate. Well-known genera from Oregon and California are, e.g., Allium, Calochortus, Fritillaria, Lilium, Trillium, Brodiae and Zephyranthes.