Nothing represents the summer season better than the sunflower. These bright and sunshiny flowers are a favorite among many, and with the right planning, you can have back-to-back blooms all summer.
Knowing when you can expect your first blooms and when to plant your last round of seeds is key, so let’s look at how long the different sunflower growth stages are.
Sunflowers take between 50 and 100 days to grow, depending on the type. Single stem sunflowers can grow from seed to bloom in 50-60 days, with dwarf sunflower varieties right after in 65-75 days. Branching sunflowers have the longest range of days to maturity, from 65 to 100 days, depending on the variety.
I’ll review when you should expect to see your sunflowers germinate, bloom, and produce seeds. I’ll also share some excellent sunflower variety recommendations and growth habits to help you get started.
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How long do sunflowers take to grow, aka “days to maturity”
When your sunflower reaches maturity heavily depends on what variety you are growing. Single stem sunflowers are grown for one useable stem and mature in the fewest days, whereas branching varieties that produce ten or more flowers per plant need the most time.
Below is a table with popular varieties of single stem, branching, and dwarf sunflowers to help you figure out exactly when your flowers will be ready and how tall you can expect them to grow.
|Days To Maturity
|Mammoth Grey Stripe
If you’re getting a late start and not sure if there’s enough time left in the season for your sunflowers, look at the days to maturity for your given variety and count backward from the first frost date in your region.
The date will tell you the last possible day that you can plant your sunflowers and have them reach full maturity.
If the variety you’re growing is not listed above, you can also check your seed packet for information on days to maturity.
Within the days to maturity are a few different stages in sunflower growth, from germination to bloom to seed. Let’s look at how long each phase of a sunflower’s life will take.
How long do sunflowers take to germinate?
You can expect your sunflowers to germinate anywhere from 3 to 14 days after you sow the seeds. If you start your seeds indoors on a heat mat, you will get the quickest germination in 3-5 days. If you plant seeds outdoors in cool soil, then the seeds probably won’t sprout for closer to 10-14 days.
Once the seeds have germinated, the seedlings will spend the next few days growing their first set of true leaves. These first few days after germination are crucial for your sunflowers, so make sure they have enough water and are in a sunny spot.
How long do sunflowers take to bloom?
Sunflowers will start to bloom anywhere from 50 to 100 days after being planted, depending on the type and variety.
There are three types of sunflowers: single stem, branching, and dwarf. Each type has a different growth habit which dictates how long the plant needs to spend growing before it turns its focus to developing a flower bud.
Most varieties of one type of sunflower will bloom within the same range of dates. For example, most single stem sunflowers will bloom in about 60 days, whether you’re growing ProCut Orange or Sunrich Gold.
If you’re growing sunflowers for an event, dipping your toe into selling bouquets, or you want to plan for succession sowing, then knowing how long the type of sunflower takes to bloom is an essential part of planning your season.
There are a few other differences between the types of sunflowers that affect how long they take to grow, which I’ll explain below.
Single stem vs. branching sunflowers
Single stem sunflower varieties only produce one bloom during the season, while branching varieties produce multiple flowers over weeks.
Because a single stem sunflower only grows one central stem topped with a flower, it matures relatively quickly in just a couple of months.
Compare that with a branching sunflower variety that grows a central stem followed by a dozen or more side branches, each of which produces a flower. Understandably, this type of sunflower needs a little more time to grow before blooming.
Of course, there are exceptions. Some branching varieties, such as Red Hedge, are quick to bloom in 60-65 days, which makes sense given that the flower tops out at three feet tall. But generally, a branching variety will need at least 70 days to mature from seed.
Dwarf varieties will generally take less time to fully bloom than larger or branching types because of their shorter heights. The average days to maturity for these short sunnies is 50-60 days, though a variety such as Teddy Bear with a complex flower will need 65-75 days.
Dwarf sunflowers top out at anywhere from 1-3 feet tall, making them ideal quick-growers for container gardens and other small spaces.
When do sunflowers go to seed?
Sunflowers will start to set seeds anywhere from 2-4 weeks after the blooms open. The petals will turn brown and die back, and the back of the flower head will dry out. The tiny florets of the center that previously had pollen and nectar will fall away to expose immature seeds below. As time goes on, the rounded ends of the seeds will be visible in the sunflower’s center.
Deadheading branching sunflowers will help extend the blooming window of your sunflowers. As long as faded flowers are removed, the plant will focus its energy on flower production rather than seeds. Single stem sunflowers won’t produce more than one strong center stalk and flower, so deadheading them isn’t very useful.
To deadhead, cut the flower stem back to just above a pair of leaves, which should encourage a new stem to appear that will produce another flower.
You might consider letting some of your sunflowers go past their prime to set seeds instead of deadheading them. Allowing the flower to go to seed will serve a different purpose, such as saving seeds or feeding wild birds.
Many larger sunflower varieties, like Mammoth Grey Stripe, are an excellent option for seed saving because their kernels are much larger, making them perfect for roasting and snacking.
If you’re saving seeds to plant again next year, make sure you save seeds from open-pollinated or heirloom plants.
Single-stem hybrid flowers don’t produce pollen and therefore won’t produce seeds at all, or they’ll develop small seeds that won’t grow true to type if planted in the next season.
Feeding wild birds
One of the best garden snacks for wild birds and squirrels is the flowers you let go to seed in your garden.
As the petals dry and fall away, what’s left behind is a nutrient-rich snack full of protein, fat, and carbs. Sunflower seeds are a great winter food source for birds because they contain high levels of oil that help them stay warm.
Don’t be surprised if you see cardinals, chickadees, nuthatches, and finches flocking to your sunflower patch when the seeds are ripe!
When should you plant sunflower seeds?
Sunflowers are great garden flowers because they’re quick growers and have a wide planting window. Knowing how long each stage of a sunflower’s growth lasts can help you plan for your season, especially if you’re succession sowing or trying to stretch your sunflower season.
If you’re in a warmer zone, like 7 or 8, you can plant your sunflowers outside around mid-March. Sunflowers are more cold tolerant than many gardeners give them credit for. It’s worth seeing how far you can push the shoulder season to get flowers earlier in the year. Some US-based flower farmers can start harvesting sunflowers by Mother’s Day in May if they’ve planted early enough.
For colder areas in zones 4 or 5, you might wait until late April or early May to direct seed your sunflowers to avoid late snow burying your seedlings. Sunflowers can take a chill but not an overnight freeze.
If you’re starting your sunflower seeds indoors, you can start them four weeks before you intend to plant them out.
Not sure when the best date is to transplant or sow seeds? You can punch your zip code into this website, Dave’s Garden, which will display your first and last frost dates for your exact location.
For step-by-step instructions on how to plant sunflowers seeds, keep reading this article for all the details: Can You Start Sunflower Seeds Indoors? (Yep, It’s Easy)