Weekly Express-News Article
By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist
Saturday, April 26, 2008
“Annual Color for Summer”
In the annual flower garden the snapdragons look great,
but within a few weeks they will begin to decline with the heat. Other cool weather flowers like cyclamen, primula,
pansies, stocks, and calendula already look pretty sad. It is time to consider replacing the cool weather annuals with hot weather
There are two cool weather flowers, however, that are exceptions;
dianthus and petunias. If you
skin the dianthus with your string mower, they will reset blooms and
look good for another two months.
Petunias, especially varieties like Wave, VIP, and Laura Bush
will tolerate considerable warm weather and may survive the summer.
Among the best summer blooming annuals are zinnias, begonias,
moss roses, and vincas.
Most nurseries in our area seem to offer Dreamland zinnia
transplants. Another option
is to grow one of the many available varieties by seed.
Dreamland is popular because the colors are strong (yellow,
red, pink, lavender and white), the stature is compact and they resist
powdery mildew for a longer period.
For best blooms you probably will have to plant one batch now
and then replace them in four months.
Plant zinnias in full sun. They are not xeriscape plants, keep them well
Semperfloren begonias are surprisingly drought-resistant.
Get them established now and they will even do well in sunny
locations if you have good soil. They do best in partial shade, however. Begonias will often provide blooms every day
through summer and winter over two or three years if the winter is
not too cold. Begonias have
pink, red, or white blooms above lush light green, dark green, or
red green foliage. They grow to about 12 inches tall.
Moss roses and the similar plant, purslane, grow low (four
inches tall), and also have drought-tolerance. Grow moss roses in beds, containers or hanging
baskets in full sun. Moss roses
have strong pastel colors. They
are available in pink, white, yellow, red, and orange.
Vincas used to be the most popular annual flower on the
market. They bloom very day
all summer until cold weather arrives. Unfortunately, they are very
susceptible to a fungal disease called aerial phytophera that melts
them down to mush if the foliage stays wet in cool weather.
New on the market they year is a variety, ‘Cora,”
that is sold as aerial phytophera-resistant. That means gardeners can begin using vincas
in the garden this time of the year instead of waiting until June
when temperatures are high and humidity is low.
If you chose to use the older
vinca selections, it is essential that you mulch around the plants
and avoid watering from overhead.
The fungal spores are splashed from the soil.
Vincas are available in pink, lavender, red, and white.
Many selections are bicolor. Vinca is very drought-tolerant and a favorite
of butterflies. Grow them in
Other summer annuals to consider are caladiums, impatiens,
and coleus. All are plants
to use in the shade and none are drought-tolerant.
Coleus and caladiums rely on foliage color for their impact. There are some coleus that are very dark maroon.
They make a striking contrast to light colored plants in the
Marigolds are an annual flower for the full sun. They look great in the nurseries now, but
rarely recommend them because they inevitably become infested with spider mites
as the summer proceeds. They are better
used as an autumn blooming annual.