Habits of Growth.
The gladiolus is a bulbous plant that grows only in the warm season of
the year. It may be grown from bulbs, bulblets, or seeds. Amateurs have
to do mainly with bulbs, as their chief object is to produce flowers.
The bulb contains the food for the nourishment of the young plant until
it has leaves, when it commences to form a new bulb close above the old
one, which latter gradually shrivels and dies, its work being done.
Meanwhile, the young plant, having roots and leaves of its own,
continues to grow and build up the new bulb.
When far enough advanced, the flower spike starts up through the middle
of the foliage and makes its appearance above the upper leaf. From the
time the spike comes in sight, the plant seems to devote the most of its
energy to developing the flowers, and the seed which follows. When the
latter is allowed to ripen, the bulb is smaller than it otherwise would
have been, and not only this, it is vertically thin, having been
partially starved by the diverting of the nourishment to ripen the seed.
On the other hand, if the spike is removed when the first flower opens,
the bulb will grow larger and thicker. Other things being equal, a bulb
is valuable according to its vertical diameter. The most perfect ones
are obtained by planting small ones, just below the blooming size. Not
being able to send up flower spikes, their vitality goes to the
production of new bulbs, and these are conical, or nearly round, which
is the ideal shape. Many florists insist upon this form when buying
bulbs for forcing. They are known to the trade as virgin bulbs. As to
the breadth of bulbs, the broader the better, other points being the
same. One that is conical in shape, and three-fourths of an inch in
horizontal diameter, will probably produce as fine a spike of flowers as
is possible to the variety, but it will yield only one, while bulbs of
larger size may send up from two to six.
Bulblets are produced during the summer, on underground stems that come
out from the base of the new bulbs. Each bulblet is enclosed in a hard
shell, which is generally brown in color, though sometimes gray, slate,
or black, and very rarely white.
Just here I will speak of the difference between bulblets and small
bulbs, for there are some confused ideas abroad on this subject.
Bulblets grow from the bottoms of bulbs, are usually attached by stems,
and have hard shells. Bulbs grow from other bulbs, from bulblets, or
from seeds, and have soft shells. They may be very tiny, no larger than
apple seeds, but still they are bulbs.
Varieties differ widely in their ability to produce bulblets. The May
and Augusta are exceedingly prolific, while the Shakespeare is just the
opposite. A bulb too small to bloom will yield many times more bulblets
than a large one of the same variety. Sometimes as many as two hundred
bulblets have been found on a single bulb.
Corm and cormel are the correct botanical terms respectively for solid
bulbs, like those of the gladiolus, and the small underground increase,
but these names are rarely used in commercial horticulture.