> Volume 58 (May/June 1991, page 89)
Growing Rhizomatous Begonias in the Ground in Southern Florida
by Paul Lowe
Southern Florida has a climate unlike that
of most of the country. Here Semperflorens are
grown mostly as annuals during the cool
season, reaching their peak in February.
Tuberous begonias will not survive our summer
heat. Among the distinctive big and
colorful-leaved types for the beginning
hobbyist, rhizomatous begonias are best suited
as low growing landscape plants. Some will do
quite well when grown under favorable shade
conditions in properly prepared beds.
Select Suitable Varieties
Some of the rhizomatous begonias that can
be found locally and that do well here are:
- B. 'Erythrophylla',
known as "Beefsteak", which has
large rounded leaves with a bronzy top
surface and reddish color underneath.
- B. 'Ricinifolia',
which has very large leaves resembling
those of the castor bean plant. Its stem
is reddish colored and delicate pink
flowers emerge on an extended stem.
- B. nelumbifolia,
which has large, rounded leaves that look
like those of a water lily and produces
large white flowers.
Other interesting rhizomatous begonias
suitable for outdoor growing can be seen at
the Mounts Botanical Garden, 351 N. Military
Trail in West Palm Beach in beds planted by
the West Palm Beaches Branch of ABS.
Prepare the Beds
While some begonias do well in half-day,
morning sun, it's a good idea to select a bed
location that is shady.
If nematodes are a problem in your area,
treat in advance. Three weeks before planting
till the area well (about the depth of a
garden spade or shovel head). Rake level and
treat with a nemacide; the soil should be
moist before application. Mix the material
exactly as directed on the container. Drench
the soil well. After application lay plastic
sheeting, available at garden shops and
hardware stores, over the treated area and
cover edges with soil to make it air tight and
wind resistant. Remove the cover after 48
hours. Do not plant for at least 3 weeks,
which allows time for the gaseous material to
evaporate from the soil.
The bed should be raised about 6"
above soil level. Use treated timbers or
concrete blocks. fill to the top with cypress
mulch (preferred for its acid properties) to
provide the good drainage important for
growing all begonias.
Carefully remove the plant from the
container, avoiding damage to the roots. Set
it in a nest in the mulch, filling in around
the plant with a good potting mix. Pile mulch
back around the plant to cover the root area.
Watering and Feeding
The bed should be kept damp, especially in
summer, but never sloppy wet. Plants should be
fertilized monthly using any good quality
soluble or liquid fertilizer at half strength.
This allows a constant level of nutrition.
The Occasional Freeze
Florida offers warm weather most of the
time, but we do get an occasional freeze.
Suggestions for dealing with the shock of low
temperatures are given by H. Alton Lee in the November-December