Plant Sunflowers for a Dazzling Display
by Pam Hones, U. C. Master Gardener - May, 2003
(Helianthus annuus) provide bright, showy and spectacular blooms in late summer.
When many other annuals and perennials are fading, sunflowers are peeking
over fences and towering against walls and houses, adding color and interest
in the approaching autumn light.
The modern sunflower is the result of centuries of seed selection
and cultivation by Native Americans in the Great Plains region and, more recently,
by growers in Russia. Their painstaking efforts have resulted in seeds with
higher oil content, plants with greater disease resistance, and the stunning
array of sizes and colors we have become accustomed to. Beyond the tall 'Lion's
Mane' sunflower popularized in Van Gogh's "Sunflowers,"
more than 100 species of Helianthus, native to North America, are available
today.
Our Napa Valley climate zones - zone 14 on the valley floor
and zone 15 in the coastal hills - provide a great habitat for sunflowers
to display their charms and produce an excellent seed or tuber crop. Sunflowers
should be planted in a location that gets full sun. They require regular and
ample water, and large-flowered kinds need rich, moist soil. If adequate water
is an issue in your garden in late summer, consider your sunflower selections
carefully.
Perhaps the most difficult part of growing sunflowers is choosing
the ones just right for you. Sunflowers can range in size from the diminutive
'Sunspot' with 10-inch flowers on a sturdy two-foot frame to the
'Mammoth Russian' or 'Russian Giant' with flowers over
a foot across on a 10- to 15-foot stalk. Some garden favorites include 'Valentine'
(multi-flowering with bright lemony-yellow six-inch flowers on five-foot plants),
'Strawberry Blonde' (pollen-free, with five-inch straw-colored flowers
overlaid with red on six-foot stalks) and 'Italian' (pale yellow
to cream with a yellow-banded and chocolate center and three- to four-inch
blooms on a four- to five-foot stem).
You can purchase seeds for specific species or packets with
mixed seeds. Many garden centers offer single seedlings and mixed six-packs.
The possible combinations are endless, but whatever you choose, you can count
on a dazzling display in your garden.
Growing sunflowers can also be a fun and fascinating way to
introduce children to plants, flowers and gardening. Sunflowers grow quickly.
They require only regular and ample water and a small amount of fertilizer
when they start to bloom. They produce large, interesting, multi-colored flowers
on "Jack and the Beanstalk" stems, and they attract all sorts of
birds and intriguing insects. Children find sunflowers hard to resist, as
do many of us who are kids at heart.
The multi-faceted sunflower also produces excellent edible seeds
that are a treat for birds. Many people also enjoy nibbling on toasted sunflower
seeds, and the oil pressed from the seed is used for cooking. Some sunflowers
(Helianthus tuberosus) are also cultivated for their edible tubers, commonly
known as Jerusalem artichokes or sunchokes.
Sunflowers do require some maintenance beyond watering. Remove
yellow leaves throughout the growing season. Stake the taller species or provide
support against a wall or house. To prevent powdery mildew, rust and leaf
spot, provide adequate air circulation by spacing plants 18 to 24 inches apart
and try not to wet leaves when watering.