Most
of the species in this genus are tender
perennials. Although they are often mistakenly
called bulbs, they are actually corms which are
stem tissue. The eyes on the sides of the corms
are buds that develop into cormels which
eventually become full sized corms. There are
some species that are reliably perennial in
temperate regions but these are not the tall,
spectacular flowers that most people associate
with the name.
Most people raise gladiolus
as an annual since the corms need to be dug in
the fall after the frost has killed the foliage.
Perhaps the most serious problem with them is
thrips which may cause discoloration of foliage
and shattering of the flowers.
The name, Gladiolus, is a derivation of
the Latin word meaning sword and is in reference to
the sword-shaped leaves.