Beating summer's heat in the garden
By Urban Harvest
we have had a relatively mild spring, with our latest over 90
degree days and high humidity, it feels like summer is upon us.
Many Houstonians believe the only way to flee the soaring
mercury is to take shelter inside an air-conditioned structure.
For gardeners and those who need to be connected to the
environment, this is a perfect setup for a bout with summertime
“cabin fever.” Though our temperate climate provides pleasurable
temperatures for most of the year, the summer months offer a
challenge to how we enjoy our gardens and outdoor rooms.
To benefit from year round use of your garden space, incorporate
elements that make it more user friendly. Here are a few ideas
you might try.
Of course this is only common sense. If you want to stay away
from the sun's heat block its rays. This can be done in two
ways, planting trees or building a structure.
Trees not only provide a shady retreat in the garden, but if
properly sited to screen your residence from the south and
western sun angles, they also significantly reduce the utility
costs for cooling it. Large, deciduous (so they can allow sun in
winter) canopy trees are the best candidates for shading both
garden and home.
Canopy trees tend to be slower growing trees, but there are
three that outpace most others Mexican Sycamore (Platanus
mexicana), Bald Cypress (Taxodium distichum) and Lacebark Elm (Ulmus
parvifolia). Start with a 30-gallon tree and in two to three
years, it will cast a fair amount of soothing shade.
Understory trees or large shrubs trained as trees are quicker to
reach mature height and still supply considerable amounts of
shade as they usually grow 15 to 25 feet tall. Sweet Bay
Magnolia (Magnolia virginiana) and Chinese Fringe Tree (Chionanthus
retusus) are spring flowering understory trees that work well in
small urban gardens.
Training a large shrub into a small tree requires pruning to
develop a trunk and branching system, but it is probably the
fastest way of getting shade in the garden, especially if you
start off with a 15 gallon plant. Typically we see Wax Ligustrum
and Crape Myrtle as tree formed specimens, but Vitex (Vitex
agnus-castus) or Almond Verbena (Aloysia virgata) are summer
flowering shrubs that would be a welcome addition to any garden.
If you want to limit shade to the garden so that plantings such
as prize winning roses or the prolific vegetable patch receive
the sun they need, a shade structure may be an option. They can
be simple or elaborate, depending upon your purpose and your
A structure with a solid roof allows the installation of ceiling
fans that not only create a cooling breeze, but also deter
mosquitoes, which like calm conditions. Enclosing the structure
with screening ensures a bug-free zone for garden enjoyment.
The structure can also be as simple as a few posts and beams
that support utility panels (a farm fencing material). Any
number of vines can be trained up the posts and over the panels
to provide sanctuary from the summer sun.
While adding water to the garden in our humid climate does not
typically have the same physical cooling properties that it does
in more arid climates, using water in the garden has a
psychological cooling effect in our gardens.
The sound a water feature provides has a soothing quality. Water
features range from gurgling bird baths to thundering fountains.
Like any built element, they too can be simple or elaborate,
depending upon your purpose and your budget.
Two ways water actually has physical cooling properties in Gulf
Coast gardens are swimming pools and outdoor showers. While
swimming pools may not be practical for most, it does not get
any easier than an outdoor shower that hooks up to the garden
hose. Many can be found online or through mail order catalogs.
Wait Until Dark
Average daytime temperatures for the summer months range from 91
to 94 degrees fahreinheit, but once the sun goes down, things
begin to cool off nicely, with temperatures averaging 72 to 74
degrees. Equip your garden with elements that add nighttime
Consider adding the outdoor lighting missing from the garden.
Lighting allows usage of the garden after sunset, when summer
temperatures are not only tolerable, but often pleasant.
Moonlighting that is placed high in tree branches produces a
soft wash over a large area and is best installed by lighting
However, low-voltage lighting can produce dramatic effects and
is easily installed by a homeowner. Simply plug in the
transformer, connect the electrical cable and snap the light
fixtures onto the cable where desired. If the cable lies in a
planting bed, simply cover it with mulch no need to dig. A
variety of systems are available on line or at your local
Finally, add plants to the garden that have an evening interest.
Look for a place to plant some Four O'clocks (Mirabilis jalapa),
Moonvine (Ipomoea alba) or Nightblooming Jasmine (Cestrum
nocturnum). Their late afternoon/evening fragrance provides
another reason to spend more hours in the garden after dark.
Any plant flowering white will shine in the garden at night and
there are a number of annuals, perennials and shrubs that would
make excellent choices. Plants with a crisp white variegation to
the leaf, such as Variegated Pinecone Ginger (Zingiber zerumbet
"darecyi") or Variegated Hydrangea (Hydrangea macrophylla
"variegate") also add a sparkle to the evening garden.
This column is produced by Urban Harvest. Learn about gardening
classes, community gardens and orchards, farmers' markets and
article was written by Suzy Fischer, who is a co-founder of
Urban Harvest and a registered Landscape Architect and principal
of Fischer Schalles, a landscape design/build firm. Contact her