University of Vermont Extension
Department of Plant and Soil Science
CHOOSING, GROWING AND USING
Dr. Leonard Perry,
University of Vermont
Petunias are among the most
popular annual flowers purchased each spring and summer. One reason
is that they come in a wide range
of flower colors and shapes. They range
in habits from mounded—good in masses or “bedded out” as bedding
trailing—good in raised beds, pots, and hanging baskets. Petunias
are easy to grow, meaning they have
few if any pest and disease problems, are adaptable to many climate
conditions, and require minimal maintenance.
are members of the Solanaceae or
nightshade family, which includes tomatoes, peppers, potatoes,
flowers such as flowering tobacco and Angel’s trumpet. This
favorite annual flower was first
discovered in South America more than two centuries ago. The
were small-flowered and lanky and were found in only two colors,
purple. But even as early as the beginning of the nineteenth
breeders were experimenting with crossbreeding to develop larger
petunias are available in shades of white, yellow, pink, blue,
purple, red, and
even black, as well as bicolors, and as single or double flowers.
Many have a
light, sweet fragrance, especially the blue petunia varieties.
last four to six days as cut flowers too.
so many colors to choose from, petunias are fun to combine into
designs. For a more striking effect, combine
contrasting colors such as yellow and purple, red and white. Or
combine a bicolor star pattern of purple
and white flowers with solid purple ones.
For a more subtle effect, combine shades of one color, as a bed of
petunias with a few darker red ones.
combine well with other annual flowers too, such as purple or white
with purple or white petunias; yellow lantana with reddish verbena
petunias; white fan flower, pink twin flower, and lavender petunias;
pink petunias with dark foliage, as from the sweet potato vine.
gardeners buy flowering plants in small pots or cell-packs, but you
your own petunias from seed if you plan ahead. Sow seed indoors
eight to 12 weeks before the
average last-frost date in your area. Since seeds are so small,
may find them “pelletted” with a casing to make them larger and
easier to handle. Sow on the surface and lightly press in, but don’t
cover as they need light
buying bedding plants, look for plants with healthy foliage and
plenty of buds.
There should be no signs of dried out or spotted leaves or
diseases. Make sure soil in containers isn’t on the
extremes—too waterlogged, or dried out.
buying, and later at home, watch for a whitish growth on leaves
which is likely
powdery mildew. If you find a grayish
growth on leaves and flower buds, this is likely botrytis disease.
Both diseases signal improper culture,
particularly lack of air circulation and too moist conditions. The
latter can happen from watering too late in the day, the plants
container planting, use a soil-less potting mix. If you're planting
the ground, choose a location with light, rich soil and good
plants about a foot apart for the mounded types, up to 2 feet apart
trailing types. Pot labels should give
you an idea on spacing. Work in some peat moss or compost before
Mulch to help keep down weeds and retain soil moisture.
prefer full sun (over six hours a day) but will tolerate partial
shade of 4 to
6 hours daily of direct sun. However, in part shade the plants will
and get leggy.
summer annuals are drought-tolerant, so once established and growing
worry about watering unless there are prolonged periods of drought.
boxes and containers, especially those located under overhanging
be checked daily, however, and watered as needed as the soil tends
to dry out
require little care but will benefit from fertilizer. Use according
label directions on your product of choice.
Those you grow from seeds may require a bit less than those you buy
pots, which are often grown from cuttings and bred to need more
fertility. If plants grow slowly, have few flowers, or light green
to yellowed leaves, and all other culture and conditions are right,
may be hungry and need more fertilizer.
the past, most cultivars (cultivated varieties) would bloom, then
back, and would then rebloom in a few weeks.
Others might bloom longer, but needed old flowers pinched off or
“deadheaded” after bloom. Most new
varieties that you find now for sale or from seeds need neither,
just fading away and dropping off on their own, with a continual
show of new
flowers. This particularly applies to
the smaller flowering selections. You
may want to remove spent flowers from the larger flowering
double types to keep them blooming longer, and more attractive.
year the National Garden Bureau chooses an annual Flower of the
Year, the one
for 2014 being the petunia. Visit their
website to learn more about the history and many types of petunias,
as well as
other popular vegetables and flowers (www.ngb.org/).