page_title: Ornamental bulbous plant
section_title: Summer dormancy
hierarchical_section_title: Ornamental bulbous plant / Environmental adaptations and distribution / Summer dormancy
caption_attribution_description: English: Crocus cartwrightianus growing near the temple at Sounion, Greece, 15 November 1991
context_page_description: Ornamental bulbous plants, often called ornamental bulbs or just bulbs in gardening and horticulture, are herbaceous perennials grown for ornamental purposes, which have underground or near ground storage organs. Botanists distinguish between true bulbs, corms, rhizomes, tubers and tuberous roots, any of which may be termed "bulbs" in horticulture. Bulb species usually lose their upper parts during adverse conditions such as summer drought and heat or winter cold. The bulb's storage organs contain moisture and nutrients that are used to survive these adverse conditions in a dormant state. When conditions become favourable the reserves sustain a new growth cycle. In addition, bulbs permit vegetative or asexual multiplication in these species. Ornamental bulbs are used in parks and gardens and as cut flowers.
context_section_description: Most bulbous plants are adapted to hot, dry summers and cooler, wetter winters. They are dormant through the summer and grow during the autumn, winter and spring. Within this group, there are variations, largely determined by how cold the winter is. Many tulips (Tulipa species) of Asian origins, for example, have adapted to an extreme continental climate, with dry, very hot summers, very cold winters and springs with short showers. They grow mainly during the spring. In cultivation such tulips may be planted in late autumn (e.g. November in the northern hemisphere). In regions where winters are milder, some species, such as Crocus cartwrightianus, flower in the autumn, either at the same time as the leaves appear or before. Others, such as Arum creticum, produce leaves in the autumn which last through the winter until the plant flowers in the spring.
  Summer drought occurs particularly, but not exclusively, in those regions of the world with a Mediterranean climate, which are rich in bulbous plants. Such regions include the Mediterranean itself through to Central Asia, the south west of South Africa, the south west of Australia, parts of the western United States, such as California, and parts of western South America, particularly Chile.
  Many species that grow in the understory of deciduous woods or forests are also summer dormant. They use their stored reserves in order to grow rapidly and complete their annual growth-cycle at the beginning of spring before the developing tree canopy blocks out the sun's light. North America is home to many such woodland bulbs, including Erythronium, Trillium and some lilies, such as Lilium pardalinum. The common bluebell, Hyacinthoides non-scripta, is native to western parts of Europe, but particularly the British Isles, where it carpets the floor of some woods. The woodlands of Asia, including China and Japan, are home to bulbous plants such as arisaemas and the giant cardiocrinums.
  Some bulbous plants grow in communities that are adapted to recurrent fires during the dry season (for example, many Iridaceae species). During these periods the plants are dormant and in this way can survive the heat of the fire. The fires clean the surface vegetation, eliminating competition and also supplying nutrients to the ground from the ashes of the burnt plants. When the first rains fall, the bulbs, corms and rhizomes rapidly start to shoot, starting a new period of growth and development sustained by the reserves accumulated in their storage tissues during the previous season.  Various South African species from the genus Cyrtanthus, for example, are well known for their ability to flower rapidly after natural grassland wildfires, and for this reason several of these species are known as "fire lilies". In fact, some species, such as Cyrtanthus contractus, only flower after a wildfire.
caption: Crocus cartwrightianus flowering on 15 November in Greece
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