Understanding bulb flowers
Bulbs are among the most interesting, most beautiful and easiest
to grow of all flower varieties. Tulip bulbs were once so prized
in Holland that it led to one of the best known financial
bubbles in history, and even today, tulips are a leading export
from that part of the world.
Even though bulbs are not quite so highly prized today as they
were in 17th century Holland, they are still loved for their
scents, their colors and their shapes, and gardeners love the
fact that most bulbs are hardy and easy to grow.
Many of the most popular varieties of flowers are actually grown
from bulbs, including tulips, crocuses, daffodils, irises,
lilies, daylilies, dahlias and snowdrops.
One thing all bulb based plants have in common is that they grow
from structures located under the ground. These underground
structures provide the nutrients and energy the plants need to
grow.
Even though bulb based plants are collectively known as "bulbs',
there are actually five distinct types of bulb plants - the true
bulb, the corm, the tuber, the rhizome and the tuberous root.
This article will provide examples of each type.
The True Bulb The true bulb is in reality an underground stem
base containing an embryonic plant. The embryonic plant
contained within the steam base already contains the leaves,
stems and flower buds, all ready to burst forth once optimal
growing conditions are provided. This setup allows the plant to
lie dormant during adverse conditions, and thus to survive
droughts and other environmental challenges. The embryonic plant
contained within the stem base is surrounded by scales (modified
leaves that overlap in a manner reminiscent of reptile or fish
scales). At the bottom of the bulb is a basal plate; this basal
plate holds the scales together and produces the roots of the
plant.
Examples of true bulbs are such popular flower varieties as
daffodils, tulips and lilies. True bulb varieties of plants are
susceptible to dryness and must be handled carefully. When
properly cared for, however, individual bulbs can live for many
years without being planted. The Corm A corm, like a true bulb,
also contains a stem base, but the tissue of the base is solid,
and it lacks the scales seen in true bulbs. The roots grow from
a basal plate which is located at the bottom of the corm, and
the growth point is located at the top of the corm.
Popular types of corms include gladiolas and crocus. Each corm
lasts for a single season, and as the corm shrinks away after
blooming, a new corm forms on top of it. In addition, small
increases, called cormels, are produced around the base of the
corm's basal plate.
The Tuber Like corm and true bulbs, a tuber is actually an
underground stem base. Unlike corms and a true bulbs, however,
the tuber does not contain a basal plate. Instead, the roots of
the tuber grow from both the base and from the sides. A tuber
will have multiple growth points spread out over its top surface.
The Rhizome The rhizome is actually a thickened stem that grows
either partly or completely underneath the ground. The largest
growth point on a rhizome is located at one end, and additional
growth points are located along the sides. The most well known
rhizome is the bearded iris.
Tuberous Roots Unlike other types of bulbs, which are actually
specially adapted stems, the tuberous root is not a true root.
Instead, fibrous roots designed to absorb nutrients and water
grow from the sides and the tip of the tuberous root. Most
tuberous roots grow in a cluster, and swollen tuberous parts
radiate out from a centralized point. The growth points of a
tuberous root are found on the bases of the old stems and not on
the roots themselves. Dahlias and daylilies are the best known
examples of tuberous roots.