Tithonia diversifolia
Common Names: Bolivian sunflower, tree marigold
Family: Asteraceae/Compositae (aster/daisy Family)
Perennial Attracts Butterflies Fast Growing Has Medicinal Uses
Flowers Useful for fresh and/or dried arrangements Fragrant
Description
Bolivian sunflower is the towering big brother of the popular
Mexican sunflower (T. rotundifolia Easily reaching up to 16 ft (5 m)
tall and more than 12 ft (3.6 m) across, this sunflower makes a
commanding statement. Bolivian sunflower has many branches and large
coarse and hairy leaves that are oblong with marginal lobes and up
to 14 in (35 cm) long. Bolivian sunflower grows fast and large
during the spring and summer, then in autumn and winter it covers
itself with hundreds of yellow-orange sunflowers, 3-6 in (7.5-15 cm)
across. Each composite flower has 11-13 ray florets and 200-300 disc
florets. All can give rise to seeds. The flowers smell like honey
and are attractive to bees and butterflies. The seeds are small and
can ride on the wind for several meters.
Location
Tithonia diversifolia occurs naturally in Mexico and Central
America. It has escaped cultivation and become established in
tropical and subtropical areas throughout the world, including South
Florida.
Culture
Light: Sunflowers need full sun.
Moisture: Although Bolivian sunflower does best in hot, dry climates
and well drained soils, it still needs plenty of water.
Hardiness: USDA Zones 9-11. Light frosts and freezes will kill
Bolivian sunflowers to the ground, but if the damage isn't too bad,
they come back in spring. Some people have had success with this
tropical in Zone 8. In frost free climates, this sunflower can
achieve the proportions of a small house.
Propagation: The easiest way to start a new Bolivian sunflower is
just to take a piece of stem, say 10 in (25 cm) long and an inch
(2.5 cm) or so in diameter, and stick it in the ground. Don't water
too much, and it should start producing roots and new leaves in a
few days. You can also plant the seeds as soon as they ripen.
Bolivian sunflower
Jack grows this Bolivian sunflower in his Zone 8 garden where it
succumbs to frost and freezes each winter and may or may not grow
back from the roots in spring. Stem cuttings taken in fall and
over-wintered indoors ensure Bolivian sunflowers for the following
season.
Usage
Bolivian sunflower is an imposing shrub and is best suited to the
larger landscape. It is a big, rangy plant and not inclined to be
neat and tidy. Several of these fast growing biggies will make a
great screen, and make it fast. Sometimes branches break off and may
take root where they lie on the ground, thus speeding the
development of the screen. Alternatively, place a Bolivian sunflower
in back of the shrub border or all alone as a single specimen. When
in bloom, Bolivian sunflower draws attention to itself. Dead-heading
is recommended to prolong the flowering season, but you may need a
bucket truck to reach the higher flowers. You can prune Bolivian
sunflower back hard after blooming to keep it from overtaking the
neighborhood.
Bolivian sunflower has various medicinal uses among herbalists in
tropical America, southern Asia and Africa. It currently is being
investigated for anti-malarial properties.
Features
Unfortunately, I can't grow Bolivian sunflower in my yard because
the squirrels and the deer eat them to the ground. The white-tailed
deer eat the leaves, and the gray squirrels eat the stems. Even
pieces of stem that I tried to start in nursery pots and hid behind
the greenhouse were discovered and eaten by the squirrels.
Researching this article, I learned that Tithonia diversifolia
leaves and stems are particularly high in nutrients (especially N, P
and K) and are used as fertilizer in tropical regions. I guess the
squirrels already knew that.
WARNING
In frost free areas Bolivian sunflower can spread and become an
invasive nuisance. The species is still relatively new to North
American gardeners and it has not yet been placed on Florida's
invasive plant list. However, Bolivian sunflower has established in
many areas of South Florida and reports are coming in that it is
causing damage to native plants. |
