10 to 13 weeks after planting. After two to three months,
The bud may initially have a star-like appearance, but once the reproductive phase is complete, you'll see your bud transform into the tall stemmed, yellow bloomed plant you know so well. It takes about thirty days for a sunflower to bloom. The reproductive phase will begin in June and end in July or August.
When do sunflowers bloom? Annual sunflowers bloom during summer and into autumn. Sow new plants every few weeks and you'll enjoy non-stop flowers until the first frost. Perennial sunflowers bloom for a period of 8-12 weeks with some beginning as early as July and others finishing as late as October.
How long do sunflowers take to grow? There are various varieties of sunflowers, and each one will grow at a different rate. On average, though, it takes between 80 and 120 days for a plant to mature and develop seeds.
Seed heads – Annual sunflowers can have either large or small seed heads, but perennial sunflowers have only small seed heads. Blooms – Annual sunflowers will bloom the first year after being planted from seeds, but perennial sunflowers grown from seed will not bloom for at least two years.
According to Robin Trott, extension educator at the University of Minnesota Extension, a “side dressing of an all-purpose slow release fertilizer applied when the sunflowers have several true leaves will speed growth and produce larger flowers.”
Sunflower care only requires a few basic growing tips. Although sunflowers require a lot of water to germinate, they only require an inch of water per week during the growing season. Use a watering nozzle to easily water once a week until the top 6 inches of soil is moist.
They do fine in soils that are slightly acidic to somewhat alkaline (pH 6.0 to 7.5). Once sunflowers get started, they can tolerate drought as befits plants whose ancestors grew happily in dry prairie regions. They are so easy to grow that they often plant themselves, springing up unbidden beneath a bird feeder.
The allelopathic characteristics of sunflowers are toxic to some plants, potatoes being one of them. This process inhibits germination and can stunt the growth of potatoes. They also compete for nutrients in the soil. Potatoes should be planted well away from sunflowers to avoid them affecting one another.
At night, in its absence, the sunflowers face east again, anticipating the sun's return. They do this until they get old, when they stop moving. Then, always facing east, the old flowers await visits from insects that will spread their pollen and make new sunflowers. Those flowers too, will follow the sun.
Sunflowers are fast reproducers, and one plant can create dozens of others. Plant seeds about an 1 inch below the ground. Germination occurs quickly, usually between 5 and 10 days, but spring crops produce more plants than summer crops. Spring crops are planted in April and May.
Do not prune annual sunflowers once the plant has set buds. Deadhead perennial sunflowers to tidy up the plant and encourage more flowers. Remove the flowers when they start to fade. Annual sunflower plants die when the flowers fade, so it's unnecessary to deadhead the plant.
From these examples, it's clear that if you plant late season sunflowers, it's best to find the variety with the quickest development, especially if you're expecting a light frost soon. Generally, the latest time for planting sunflowers will be in July or late August.
Sunflowers continue to be an important oilseed crop worldwide. Many of them are used for birdseed but most are processed into vegetable oil. The green stalks are chopped like silage and used as cattle feed. The seeds and green foliage are favorite foods of many birds, mammals, insects, and butterflies.
Choose a full-sun location: Six to eight hours of sunlight per day is ideal for growing sunflowers. Give your flowers space to grow: Plant seedlings at least 12 inches apart, as the sunflowers will spread out over time and grow best when they have plenty of room.
Shorter types with a single head may start blooming less than two months after the seed is planted, while giant sunflowers may not start to bloom until 3-4 months after planting. Some varieties can grow multiple flower heads, extending the blooming period until the first fall frost.
One of the fastest flowering varieties, 'Ruby Eclipse' (pictured above, right) is an attractive branching sunflower that's as productive as it is beautiful. Blooms are a mix of bicolor flowers in shades of cream, dusty rose, and ruby-red. Super easy to grow, with one planting producing for 3 weeks.
Sunflower seedlings should be watered daily so the soil is moist but not soaked. As the sunflowers become established, they can be watered once a week.
Remove sunflower root balls from the soil.
Once dislodged, sunflower root balls should be removed from the soil as much as possible, as it will be hard to plant around the tough roots. The woody root and stalk won't compost very quickly, so consider burning them instead.
Don't spray any plant during a heat wave. You will do the leaves more harm than good. Your goal is to minimize the stress they are under by protecting them from the sun if you can, and by watering deeply once a week to encourage deep root growth. Shallow roots arise when plants are watered frequently for short periods.
New tips will be abnormal and look like they stopped growing abruptly. Pretty soon, the plant will begin shedding leaves. The leaves, apart from turning yellow, may also turn brown or black, depending on the issue. If the plants are overwatered, they will begin to wilt too.
There are pint-sized sunflowers that grow just a foot tall and giant varieties that reach for the sky, but you don't need a big garden to grow sunflowers. These classic summer bloomers can be planted in plastic pots, fabric planters, or even buckets.