Sunflower:
Sunflower (Helianthus annuus .L) is one of the few crop species that originated in North America (most originated in the Fertile Crescent, Asia or South or Central America). It is a twelve-monthly plant. The sunflower got its name from its huge fiery blooms, whose shape and image is often used to represent the sun. The sunflower has a rough, hairy stem, broad, coarsely toothed, irregular leaves and circular heads of flowers. The heads consist of 1,000-2,000 individual flowers joined together by a receptacle base.
Sunflower seeds were taken to Europe in the 16th century where, along with sunflower oil, they became a wide-spread cooking ingredient. Sunflower leaves can be used as a cattle food, while the stems contain a fiber which may be used in paper production.
History
Sunflower was probably primary introduced to Europe through Spain, and spread through Europe as a curiosity until it reached Russia where it was readily adapted. Selection for high oil in Russia began in 1860 and was mainly responsible for increasing oil content from 28% to almost 50%. The high-oil lines from Russia were reintroduced into the U.S. after World War II, which rekindled interest in the crop. However, it was the discovery of the male-sterile and restorer gene system that made hybrids feasible and increased commercial interest in the crop. Sunflower acreage is now moving westward into dryer regions; however, 85% of the North American sunflower seed is still produced in North and South Dakota and Minnesota.
Scientific Classification
Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Asterales
Family: Asteraceae
Genus: Helianthus
Species: Helianthus annuus
Description
With sunflower, what is usually called the flower is actually a flower head (also known as a composite flower) of numerous florets, (small flowers) crowded together. The outer petal-bearing florets are the sterile ray florets and can be yellow, red, orange, or other colors. The florets inside the circular head are called disc florets, which mature into seeds.
Sunflowers most generally grow to heights between 1.5 and 3.5 m (5–12 ft). Scientific literature reports that a 12 m (40 ft), traditional, single-head, sunflower plant was grown in Padua in 1567. The same seed lot grew almost 8 m (26 ft) at other times and places, including Madrid. During the 20th century, heights of over 8 m have been achieved in both Netherlands and Ontario, Canada.
Heliotropism
A common misconception is that sunflowers track the sun. In fact, mature flower heads typically face east and do not move. The leaves and buds of young sunflowers do exhibit heliotropism (sun turning). Their direction changes from east to west during the course of a day. The leaf and flower head bud phototropism occurs while the leaf petioles and stems are still actively growing, but once mature, the movements stop. These movements involve the petioles bending or twisting during the day then unbending or untwisting at night.
Varieties of Sunflowers:
There are many types of sunflowers. And, gardeners like to grow a wide variety of them.
•Sunflowers are basically separated by size. The giant varieties grow over ten feet. Regular sunflowers typically grow from six to ten feet. Miniatures are gaining in popularity as borders. They are very popular in Asia, and grow two to four feet.
•Some varieties of sunflowers have one big head or flower. They are usually the giant sunflower varieties. Other large headed varieties, have a few much smaller heads that form on lower branches. Some varieties have multiple heads. These are typically midsized sunflowers, and are perfect for flower gardens in attracting birds.
•Sunflower seeds are usually a dark brown to black, or large, grey and white striped. The latter is the most popular for eating due, to their large size. Don't worry over selection. The birds will eat ample quantities of both, and so will you. Whether you are feeding the wildlife or not, there are plenty of wildlife that enjoy sunflower. They include all sorts of birds of course, squirrels, and rodents.
•Giant Sunflowers - Many people find growing these to be addicting. A giant sunflower can be either a very tall plant, or an enormous flowerhead.
•Tithonia, or Mexican Sunflower- Grow 4-6 feet tall, with daisy-like flowers. Blooms summer to fall.
Cultivation
To rapid grow, sunflowers need full sun. They grow most excellent in fertile, moist, well-drained soil with a lot of mulch. In commercial planting, seeds are planted 45 cm (1.5 ft) apart and 2.5 cm (1 in) deep.
Sunflower plants grow well in average to rich soils. They need to grow their roots deep and wide, to enable them to withstand strong winds. If you have a choice, sandy soils are not recommended, as they are easily uprooted in loose soil. Rich soil is important, when growing giant varieties.
Deep roots help sunflowers to withstand most droughts. They will benefit from a dose of fertilizer when you apply it to the rest of your garden. Apply extra phosphorus and potassium when the flower bud begins to develop, to promote bigger blooms.
Tip: If you are crowded for space, plant one or two sunflowers amidst your vine crops. One or two will not seriously shade the vines. Make sure not to plant them near their tap roots for the vines.
Harvesting:
Harvest sunflower seeds after the flower begin to die back, and most if not all, of the petals have fallen off. Pull out a seed and open it to see if it is full. Cut off the head, leaving a few inches of stalk. Hang the stalks to dry in a well ventilated area. Do not stack them in a box, as mold can develop during the drying process. As soon as the flowers have dried, extract the seeds by rubbing two flower heads together. They should come off of the flower head fairly easily. Sunflowers are also used as dried flowers in vases and for craft projects. They can be cut just before the flowers die off and dried over a few weeks. Miniature sunflowers make lovely fresh bouquets also. For craft projects, it is important to leave a sufficient amount of stalk.
Uses
Sunflowers “whole seed” (fruit) are sold as a snack food, after roasting in ovens, with or without salt added.
It is also sold as food for birds and can be used directly in cooking and salads.
American Indians had various uses for sunflowers in the past, such as in bread, medical ointments, dyes and body paints [citation needed].
Sunflower oil
Sunflower oil, extracted from the seeds, is used for cooking, as carrier oil and to produce margarine and biodiesel, as it is cheaper than olive oil. Commercially available sunflower contain from 39 to 49% oil in the seed. In 1985-86, sunflower seed was the third largest source of vegetable oil worldwide, following soybean and palm. The growth of sunflower as an oilseed crop has rivaled that of soybean, with both increasing production over 6-fold since the 1930s. Sunflower accounts for about 14% of the world production of seed oils (6.9 million metric tons in 1985-86) and about 7% of the oilcake and meal produced from oilseeds. The oil accounts for 80% of the value of the sunflower crop, as contrasted with soybean which derives most of its value from the meal. Sunflower oil is generally considered a premium oil because of its light color, high level of unsaturated fatty acids and lack of linolenic acid, bland flavor and high smoke points. The primary fatty acids in the oil are oleic and linoleic (typically 90% unsaturated fatty acids), with the remainder consisting of palmitic and stearic saturated fatty acids. The primary use is as a salad and cooking oil or in margarine. In the USA, sunflower oils account for 8% or less of these markets, but in many sunflower-producing countries, sunflower is the preferred and the most commonly used oil.
