Weekly Express-News Article
By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist
Saturday, June 23, 2007
“Summer Container Garden”
Even if you have a large lot and plenty of room for landscape
and garden, container plants can contribute to your gardening
experience. Container plants are even more important to gardeners
without much space. They can be used in sun or shade, provide
summer long color, and attract butterflies and hummingbirds to
the patio. The actual container can be as decorative as the plants
it holds. Larger containers can even be used for fruits and vegetables.
The larger the container the larger the plant they can support.
Half whiskey barrels are ideal, especially if you mount them on
wheels for large plants like citrus or tomatoes. Red clay pots
are the classic container. They do not last as long as black plastic,
but do a better job of insulating root tips. Decorative ceramic
pots can be works of art that complement the plant they hold and
make the patio worthy of a spread in “Good Housekeeping”.
To be useful the container must have sufficient drain holes. The
diameter of the drain holes should be 10% of the diameter of the
top of the container (10 inch pot, 1 inch drain hole). Use high
quality potting mix and only fertilize with soluble or granular
fertilizers made specifically for containers. Osmocote and granular
hibiscus fertilizers work well. Containers need to be watered
more frequently than gardens in the soil because the root system
is more limited, the soil reservoir is small and pots can heat
up more than gardens in the soil or raised beds. Water when the
soil dries to 1 inch.
Citrus make exemplary plants for containers. Satsuma orange,
Meyer lemon and Mexican lime work especially well. In a half whiskey
barrel they will produce high quality fruit every year. Some winters
they will have to be covered to protect them from freezing temperatures,
but they are drought-tolerant. In additions to the fruit the foliage
and blooms are outstanding. The evergreen foliage is shining green
and the white flowers have a wonderful fragrance. The container
limits the size of the plant to about 3.5 feet tall. Citrus require
full sun to produce fruit.
Oriental hibiscus are classic container plants for the summer
in full sun. The foliage is shiny green and almost as attractive
as citrus leaves. The best hibiscus plants produce blooms everyday
from April to November. There are doubles and singles in red,
yellow, pink, white, orange and bi-colors. Oriental hibiscus do
have to be protected form the cold in the winter. They do well
in 12 inch or larger containers. Hummingbirds will use hibiscus
as a nectar source.
Pentas prosper in the shade or sun. Pentas in containers bloom
every day all summer. They are available in red, pink or lavender.
Pentas are tropical plants so they must be put in a greenhouse
in the winter if you want to use them more than one year. Besides
the constant bloom and shade tolerance, penta’s claim to
fame is their attractiveness to hummingbirds and butterflies as
a nectar source.
Purslane and moss rose are low growing drought-tolerant plants
for hanging baskets or small containers. They produce a show of
rose-like flowers white, red, pink, orange, lavender and bi-colors.
Purslane and moss rose require full sun.
Begonias can tolerate sun if they are established early enough
in the season, but they are especially useful for color in the
shade. There are red foliage and green foliage versions with red,
pink and white blooms that make a show all summer long and even
do well in the winter if the weather is mild. Begonias are surprisingly
Sago palms are not really palms, but they are just as drought-tolerant
and pest free as palms. If scale occurs, treat with summer oil
and acephate. Sago’s do fine in light shade and full sun.
The tropical looking upright foliage is very attractive and gives
the patio the feel of the tropics. The Sago is very tough and
less cold sensitive than most citrus.
Zinnias are sun loving flowers. They last about four months in
a summer garden or container. Many selections can be grown from
seed, but the best choice for San Antonio gardens seems to be
the Dreamland transplants available at most retail nurseries.
Zinnias provide great color – red, lavender, white, yellow,
orange and pink. There are small zinnias (Thumbelina and others),
but most varieties will fill a 3-5 gallon container. Deadhead
spent flowers for the most attractive and continuous bloom. Both
butterflies and hummingbirds seek zinnia nectar. Zinnias use lots
of water so keep them moist.
Tomatoes do well in a half whiskey barrel, but peppers are even
more attractive and do not require as large a container. They
also tolerate the summer heat better than tomatoes. With peppers
you would not have a period between late June and early August
where the container would be empty. Use the red hot peppers and
yellow banana peppers for useful vegetables and lots of color.
There are unlimited selections of ornamental peppers. All have
colorful fruit and shiny attractive foliage.