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.