Information about growing sunflowers, Helianthus sunflower perennials, and tips for how to grow sunflowers from seeds.
Many gardeners enjoy growing perennial sunflowers because they they flower with such an abundance in summer and into fall, and they also provide seeds for the birds in the winter.
Perennial sunflowers do not have the enormous huge blooms that their annual sunflower cousins have, but they are such prolific bloomers that perennial sunflowers will give you garden just as much impact. Plus they grow back every spring.
Sunflower Growing Tips
Light and Soil Information
Perennial sunflowers grow and flower the best when growing in full sun.
However there is a thin-leaved sunflower that actually prefers to grow in light shade.
All sunflowers grow well in just average soil that drains well. They don’t like soggy soils though.
Established sunflower plants are actually quite drought-tolerant, but likes ample moisture as well, as long as the soil is well-draining.
How To Plant Sunflowers
I wrote a whole page about planting sunflowers either from purchased plants or from seeds.
Just click on this link to get detailed planting instructions.
Dividing and Propagating Sunflowers
Perennial sunflower clumps do tend to get large after a few years, and should be divided in spring after 3-4 years.
You can divide them sooner if they don’t bloom as much as they used to.
Dividing sunflowers is also a very simple way to propagate the plants.
Potential Growing Problems
Possible problems you may encounter are aphids, caterpillars, plant bugs, slugs and snails, powdery mildew and rust.
However, these are usuallly not serious enough to need control or spraying.
But I do recommend baiting for slugs and snails though, if they are a problem in your area.
Sunflower Summer Care
I have found that very tall perennial sunflowers are prone to sprawling toward the end of summer.
It can be a bit hard to stake very tall plants, so I recommend pruning them to control their size. It’s much more practical and a lot less work.
Here is how you do it: Cut them back by about one-half in early summer, before buds are forming. and then again by about one-third in midsummer if needed.
On the later blooming sunflower varieties. such as the swamp sunflower, the Maximilian sunflower, and the Willow-leaved sunflower, you can cut again in late summer.
If you want these giant sunflowers to be much shorter at bloom time, cut them back as much as two-thirds in late summer.
You will usually still get blooms before frost, at least in warmer climates.
Stop pruning once the flower buds form
Flowering may begin by midsummer for some species, others start in late summer, or even later.
If you don’t have any rainfall, keep watering new spring plantings.
Established perennial sunflowers also benefit from an occasional soaking during pro-longed dry periods.
Growing Sunflower Seeds
Sow seeds of perennial sunflowers in containers in a cold frame in the spring, according directions on the seed packets.
Sow the annual sunflower seeds when the weather reaches at least 61 degrees F (16 C). Always follow the directions on the seed packets for success with growing sunflowers.