Crocuses store food over the winter.
Many plants store food over the winter season. Every deciduous plant, evergreen or perennial has some means of sustaining itself though winters that range from the slight drop in temperature and dry conditions in the U.S. Southwest, to similar temperature changes with rain in southern Florida, to the drastic drop in temperature with heavy precipitation such as the harsh winters of New England.
Bulbs
True bulbs are categorized into two types: tunicate bulbs, such as tulips, alliums, hyacinths and grape hyacinths, which have brown thin outer leaves called tunics, and imbricate bulbs, such as the lily, which do not have the protective tunic. These perennials store nutrients in their modified fleshy leaves (visible storage rings) that surround the flattened rosette stems (containing the leaf bud and developing flower) inside the bulb. In cool dry climates, where temperatures drop to 50 or 55 degrees, succulents such as cacti (i.e. bird's nest, Christmas cactus, donkey's tail, golden star, powder puff and string-of-beads) also store their nutrients in water found in these fleshy leaves.
Rhizomes
Iris, ferns, lily-of-the-valley and cattails are rhizomes, having underground stems that store food in the roots that project along their lower surfaces. These potentially invasive plants grow horizontally under the soil's surface.
Corms
Crocus, gladiolus and autumn crocus come from corms (a swollen vertical stem base that expands into massive underground storage tissue containing nutrients) and do not have fleshy leaves, but dry, scaly, leafy coverings. Even though corms only live for one season, the old corm produces new corms at its side or top, which contain nutrients in their stems for the next growing season.
Tubers
Tubers (potatoes, Caladium, anemones and oxalis) have swollen sections of underground stems that hold nutrients. They start storing food when temperatures get below 68 degrees F and the days get shorter.
Taproots
Taproots such as mint, dandelions, rose bushes, apple, plum, and cherry trees, strawberries and shrubs such as rhododendrons, blueberries and azaleas store nutrients in the main root (an elongation of the stem) that grows deep into the soil. Dahlias have tuberous roots that are modified taproots where actual storage is in the hard root, not in an enlarged stem. Sweet potatoes have tuberous root underground storage organs as well, as do horseradish, carrots and turnips, parsnips and beets.
Fleshy Roots
Peonies and daylilies store nutrients in their fleshy roots.
