cold it gets in your area is one of the most important factors in determining
which bamboos will grow well for you. Gardeners in South Florida have
the greatest range of bamboo diversity to choose from, and the further
north in the state you live, the fewer the choices. However, even those
of us in the "cold country" of North Florida have some excellent
bamboos available to us that can handle a hard freeze, especially if
some basic precautions are employed.
The most cold hardy of the bamboos offered by Florida Bamboo are the Bambusa multiplex
varieties (Green multiplex, Alphonse Karr, and Chinese Goddess), which can take temperatures down to the lower teens with little to no damage. These should do well in most North Florida locations.
Next in hardiness is Royal, which is very nearly as cold tolerant as Bambusa multiplex, handling temperatures down to the mid-teens. Buddha's Belly and Blue Bamboo are next, taking temperatures to about 18 degrees. The least cold hardy of the varities we sell is Giant Timber, which is good to about 20 degrees and is recommended only for central and south Florida.
These temperature figures are very approximate. They represent the approximate level below which a bamboo plant will have substantial damage to the above-ground portions. It's not lethal if the temperature does dip below this level, it just sets back the plant's growth.
Around the state, there are many "cold pockets" and "warm
pockets" that can be determined only by experience, but in general, the
three factors that contribute to determining winter lows for your area
are: (1) How far north you are; (2) How close you are to the ocean or
other large bodies of water; and (3) How close you are to an urban area.
The most freeze-prone areas of Florida, correspondingly, are inland,
rural areas north of about the latitude of Gainesville. Within the
Gainesville developed area, an urban "heat island" creates milder winter
temperatures, and heading south from Gainesville, the winters become
steadily warmer, so if you are in urban/suburban Gainesville, or south,
the Bambusa multiplex varieties, Royal, and Buddha's Belly should do well for you.
If, on the other hand, you live out in the country north of
Gainesville (or if by chance you are in an exceptional cold pocket south
of that area), you can still grow these varieties, but you should pay
attention to some precautions about cold for best results. The most
important factor is that coverage of the sky by buildings or evergreen
trees offers considerable protection to bamboos. The greater the
percentage of sky that is covered, the greater the protection.
Of course, more sky coverage will reduce the sunlight reaching
the plant, which is needed for growth, so it may be necessary to
compromise, selecting a planting location that has sky coverage to the
north, east and/or west, but is open to the south, or at least open
directly overhead, so the plants get at least a few hours of sunlight.
Summer is the season of maximum growth, and in the summer the sun passes
almost directly overhead, so a patch of sky directly overhead can allow
for good growth in a plant surrounded on all sides by trees or
The benefits of this technique of selecting planting sites with
evergreen sky coverage can be quite dramatic. In the accompanying
photos, both plants are the same variety of bamboo photographed a couple
of weeks after a night in which a thermometer on the property
registered a low of 15 degrees (this was in one of those "cold pocket"
areas north of Gainesville). One of the plants was situated in an open
field, the other was a couple of hundred feet away in a spot with trees
around it (the partially defoliated plant will sprout new leaves in
spring, but it will spend a couple of months looking less attractive
than it could be).
Another important technique is simply to plant in early spring,
rather than later in the year. As a bamboo plant gets bigger, it gets
more cold hardy, so planting in early spring gives the plant the maximum
time to get larger before winter comes around again. For plants that
are still fairly small when a hard freeze is predicted, wrapping the
plant with burlap or blankets as high as you can reach can help minimize
damage the first winter or two, when it is most vulnerable. Also,
giving your bamboos the best growing conditions possible, with regular
watering, keeping the soil thickly mulched, and fertilizing periodically
will help speed growth and turn your plants into larger, more
cold-resistant specimens faster.
These techniques can also be useful for pushing the limits of
those bamboos listed as recommended only for Central and South Florida.
For example, if you live near the downtown area of Gainesville, plant in
spring, take good care of the plants,
and are willing to throw covers around them if there's an exceptional cold spell their first winter or two,
you probably can grow an excellent stand of Giant Timber (Bambusa oldhamii).
One important note about all of this: We're not talking about
the plants being killed altogether here, so you shouldn't worry about
losing your plants. Bamboos exposed to more cold than they can handle
will first suffer leaf and twig damage (the plants can easily leaf out
again after a couple of months of warm weather), or if the cold is
extremely severe, all the above-ground growth can be killed, but the
underground rhizome system will still be alive and will send up new
shoots in spring. A bamboo plant could freeze to the ground every
winter and still come back every spring, putting up an annual display
of green foliage every summer, but it would not reach the full size for
the species or make as good of a visual screen. So don't interpret this
section as a warning of the danger of losing your plants; it's really
about allowing them to be able to properly strut their stuff!
Winters in Florida are very variable, and there is always the
possibility that next winter will bring a once-in-fifty-years freeze for
the record books. If this should happen, you will be very fortunate to
have landscaped with bamboo, as opposed to palm trees, for instance. A
palm tree exposed to more cold than it can handle is instantly
transformed into some very expensive firewood, while bamboo will come
back and can regain much of its former stature and beauty in just a
couple of growing seasons.