57 (January/February 1990, pages 25 - 26)
Spotlight on: B.
by Mary Weinberg
B. gehrtii was
discovered in Brazil, and described by
Irmscher in 1959. It is in Section Pritzelia.
B. gehrtii is a
rhizomatous begonia with distinctive foliage.
Leaves are large, ovate, crispy, shiny, rugose,
and medium green in color with sparse tan wool
over the upper surface. The leaves have an
elongated basal lobe which overlaps to form a
small opening at the leaf base. Veins are pale
green in color. The underside of the leaves
are pale green with sparse tan wool on the
veins. Petioles are cylindrical and tomentose.
Flowers are white. Bloom occurs in winter.
B. gehrtii grows
best with cool temperatures. It is best grown
in the house or in a shady location within the
greenhouse during the summer months, as leaf
burn and wilt caused by breezes and overly
warm temperatures will leave your plant with
many damaged leaves in a very short time. I
have been most successful at growing B.
gehrtii in the basement during the summer,
as this area is at least 10 degrees cooler
than the rest of the house.
There are two plants
that look very much like B. gehrtii: B.
paulensis A. DC. and B. moysesii
Brade. Both plants have the same leaf color
and texture as B. gehrtii but there are
distinct differences. B. paulensis'
leaf is eltate, with a more rounded shape. B.
moysesii has the elongated basal love of gehrtii,
but their petioles differ: moysesii has
a four-sided petiole and no hairs.
There is another
likeness between B. gehrtii and B.
paulensis. Both plants have leaves that
will root as cuttings, but never form a
plantlet from the leaf.
Light: Good light
is essential, but do not place this begonia in
the sun. In a greenhouse, give it a shady
location. Under light garden conditions it can
take a much brighter situation.
Comfort range for B. gehrtii is 65-75 degrees
F., but it takes temperatures in the lower
60's very well.
humidity is 50-60%
Water: Give water
when the soil feels slightly dry to the touch.
If allowed to dry beyond this point leaves
will look pale and limp. Note: a good time to
transplant B. gehrtii is when the soil
is slightly dry, as leaves will be more
flexible; gehrtii's leaves are normally
quite crisp and tend to crack when handled.
Use a mix that will retain some moisture, but
still have good drainage.