In a more perfect world,
developers and builders would remove the absolute minimum
number of plants possible from a building site. This has rarely
been done in the past, nor does it seem likely to be done
very frequently in the future. Consequently, instead of having
a landscape that had developed in situ without attention,
pampered nursery-grown plants are brought in to landscape
properties that will have been considerably altered from their
original state. The question is what kind of plants will be
able to survive and thrive in the altered environment with
minimal inputs of water, fertilizer and pesticides.
One answer would be to put back most if not all of the plants
that were present on the site before construction. Since construction
will most likely have changed the soil composition and drainage
as well as light patterns, the plants that thrived before
construction may no longer be the best suited for their previous
sites. If you are interested in plants that can thrive without
a lot of help, however, you will have to carefully select
those that can meet such requirements. Plants native to this
area of Florida have evolved mechanisms over the centuries
that enable them to handle our climate. Hot dry weather in
the spring, followed by even hotter wet and humid summers
in infertile soils, is a regime that many non-native plants
find difficult unless considerable external inputs are employed.
In addition, native trees have had to be able to withstand
the frequent hurricanes and tropical storms to which Florida
is prone.
It has been argued that while native plants can survive well
under undisturbed conditions, the proof for their superior
survival under the disturbed conditions of a building site
has not been obtained. While rigorous proof for their superior
survivability may be lacking, native plants have at least
evolved under the difficult Florida climate that alternates
drought with flooding, and they have grown in soils with limited
fertility under natural rainfall. Plants not native to this
area may lack the ability to thrive here without large inputs
of water and fertilizer, and may be overly prone to disease.
As always, plants should be selected for their ability to
thrive on the particular microsite.
An important attribute of native plants is that they are necessary
in maintaining populations of many types of native fauna including
birds, butterflies and a wide variety of crucially important
insect pollinators. In Britain it has been found that native
trees such as oak and hawthorne support several hundred invertebrates.
The widely planted imported horse chestnut supports only four
invertebrates in Britain, although a hundred or more colonize
it in its native Mediterranean area. These invertebrates are
food sources for birds and other wildlife, and the replacement
of native species with introduced ones can disrupt many food
chains. As more land is developed, urban and suburban areas
become more important for wildlife.
Another important role for native plants in urban areas is
aesthetic and more subjective. We obtain our sense of place
in many instances from the flora without even knowing the
identity of the plants. One of the ways we know we are in
Florida and not in Ohio, other than the absence of winter
snow, is the presence of massive live oaks and stately cabbage
palms as well as other less well-known plants. Non-native
plants have their place in our urban spaces, but surely the
almost total replacement of our native flora with exotics
is comparable to replacing all of our native birds with species
of parrots because we enjoy their colorful plumage.