Sunflower

Helianthus annuus

Tournesol

Sunflowers are fairly versatile; height varies, as does soil and lighting preferences. There are many species native to Canada. Provides long summer bloom for the perennial border or cutting garden. Also effective in a native plant or wild garden or as part of a naturalized planting or prairie area.

Sunflowers are high in nutrients, including protein and vitamin E, and low in saturated fats. They attract birds, bees and butterflies.

Sunflowers are considered heliotropic, which means the flower moves with the sun, from east to west, and then at night back to facing east, again awaiting the morning sun. The tallest ever sunflower recorded was 30 feet and 1 inch tall.


Sunflowers grow best in full sunlight, at least 6-8 hours per day in moist well-draining soils.

In nature prairies and other grasslands, old fields, roadsides, railroad rights-of-way, savannas, and forest edges.

Coming from the greek words “helios” (sun) and “ethos” (flower), the sunflower is an exceptional plant with many different attributes. It blooms from mid-summer to early fall. There are quite a variety of different sunflowers, some with branching stems or single stems, some that produce pollen for pollinators and some that don’t, small or large varieties, some that produce edible seeds, and so on.

Video on Helianthus annuus


Planting Helianthus annuus

It is best to sow seeds directly into the soil, after the risk of frost has passed and the soil is at least 10oC. Ensure the roots have enough space to stretch out. When preparing a bed, leave space of about 2 feet down and 3 feet across. Fertilizer or compost is recommended as sunflowers prefer nutrient-rich soils. With larger varieties, it is best to plant them where they are sheltered from strong winds, such as near a fence or a building, as their tops become heavy and wind impact could be devastating.

Companion plant suggestions include prairies and other grasslands, old fields, roadsides, railroad rights-of-way, savannas, and forest edge

Caring for Sunflower

Easily grown in average, dry to medium, well-drained soil in full sun. Tolerates drought, but does best if regularly watered.
Remove spent flowers to extend bloom season.

It is happiest in Tolerates a wide range of soils

In terms of water, Sunflower needs Tolerates drought, but blooms best when watered consistently.

Pruning Tournesol

Plant stems may be cut back by 1/3 to 1/2 in late May to reduce overall plant height. Sunflowers dislike having their roots disturbed and transplanting is not recommended. For bouquets, simply cut the stem above any new side blooms in the early morning. They should last about a week in a vase if you change the water daily.

Other

Birds and squirrels will browse the seeds. To avoid this, deter them with barrier devices. If a small moth lays its eggs in the blossoms, simply pick the worms from the plants. Rust and powdery mildew may also affect sunflowers.

Slightly acidic to somewhat alkaline soils (pH 6.0-7.5)

Alongside eating the seeds, Native Americans also used the oils to cure skin ailments. Dyes were also made from the yellow flower and the black seeds. According to many sources, Helianthus annuus is reported to be one of the first crops grown in North America.