Guide to growing Sunflower - Helianthus
Helianthus are a large genus of plants that can be grown as Hardy perennials or hardy annuals.
They are better known as sunflowers, and both sunflower oils and sunflower seeds are of great commercial and health value.
Most people associate Helianthemum members with great height (between 1.5 to 3 metres), but some dwarf varieties that only reach 45 cm in height are available.
They carry large daisy like flowers, mainly of Yellow or orange, but sometimes cream, that flower from the middle of summer until the middle of autumn.
Sunflowers make great plants to show off, and they can also be used as tall plants at the back of borders.
How to grow Sunflower (Helianthemum)
If growing Helianthemum outside then it is best to sow sunflower seeds outdoors at a depth of 6mm following the last frost of spring. Sunflowers like to grow in a sunny or partially shaded area that has good drainage. they can be grown in most soils but if you want to grow big sunflowers then use a soil that is of pH5 to 7, deep and rich.
You can start to grow sunflowers indoors first. When planting sunflower seed indoors sow them in peat pots about three weeks before the last frost of spring. They will take about 10 days to germinate at a temperature of 21 to 30 degrees centigrade. The sunflower seedlings should then be transplanted about a metre apart after the last frost of spring.
Caring for Sunflowers
Sunflower care is pretty easy; If you want to create bushy sunflowers then they should be pinched back when they are young to encourage branching. Due to their large heights it is important to stake sunflowers to protect them from windy conditions; especially if growing solitary. Helianthemum will require lots of watering but only feed them lightly to produce health flowers. Although sunflowers are pretty easy to look after, it is difficult to grow other plants around them as they carry toxins in their roots that act to give sunflowers a competitive advantage over other plants.
Harvesting sunflower seeds
If you require the sunflower seeds for culinary use, then they should be protected from birds during seed maturation, this can be done by placing a linen or cheese cloth over the head of the sunflower.