How to Grow Sunflowers for Cut Flowers
Growing sunflowers for cut flowers brings dramatic bouquets into your home. They can grow in rows or in beds, with some growing big and branchy to make glorious hedges for a large summer garden. I love the way they greet the morning sun with their faces and follow it until it sets.
Cutting sunflowers are easy to grow. You can start them early in cells or pots but it’s best to sow directly into your garden bed.
There are so many different beautiful varieties to choose from, just be sure you select a cutting variety.
With proper harvesting and post-harvest handling you can get up to two weeks of vase-life from cut sunflowers.
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What the flowers are like
Sunflowers can be very large, up to 12 in. across to just a few inches across. For cutting flowers, most are around 4-8 in wide from the edge of the petals, with disks that are several inches wide to just an inch or so.
They come in an ever increasing array of colors, from almost white, to lemon yellow, butter yellow, to orange and peach, and on to reds, browns, and even almost black! And there’s a couple varieties that are mostly calyxes… they’re interesting—one with a purple tinge.
Pollenless sunflowers? Why?!?
Many good cutting sunflowers are pollenless. This means they’re bred to not produce pollen.
The reason for this is that when you bring in your sunflower bouquets, the flowers will not drop pollen all over your table. Sunflowers are good at producing and dropping pollen, and many are big. So breeders have come up with varieties that don’t produce pollen or at least very little.
Now, you may think that’s ridiculous, that it deprives the bees of a much needed resource. But when you harvest your sunflowers, you pick them before the pollen is produced. So when the pollen does show up, your flowers are inside, on your table, unavailable to the bees.
If you want to supply the bees, choose a non-pollenless variety, pick some for bouquets, and leave the rest for the pollinators. There is a downside to this, though, which I’ll describe in Harvesting, below.
Pollenless sunflowers do produce nectar, and I see plenty of bees on mine. And if you do want to do more for the bees, read about how your flower garden really can help them and find out which flowers to plant to help them.
What sunflower plants are like
Sunflowers can be branching or not. Branching sunflowers tend to branch naturally which means they produce more flowers overall. With some pruning (see below) you can get them to form side branches with longer side stems that are best for cut flowers. They also yield smaller flowers overall.
Non-branching grow a single thick stem and most produce a single flower. The flowers are really beautiful, large but not like the monster ones grown for seeds, and many are pollenless, great for cut flower production. But, unless you have a large garden your growing space will be put to better use by growing the branching sunflowers.
How to grow sunflowers for cutting flowers
Full sun: at least six hr. each day; but their name indicates they want all the sun they can get! Average to good garden soil.
Sow seeds directly into the soil, after all danger of frost has passed.
For branching sunflowers you can give them up to 2 sq. ft. each. For non-branching space much closer, about 9 in. apart.
Water deeply and infrequently so they develop deeper root systems. That means not every day; water deeply and let dry out between waterings after they are up and established.
How to harvest sunflowers
Harvest when petals are just opened but before the florets in the disk are open.
Cut stems just above a node and far enough down the stem to allow nice long stems to grow to produce more cut-worthy flowers.
Here’s how to get more good cutting flowers from branching sunflowers:
- Your first cut must be at a node that is low enough to allow two new stems to grow from the node with stems long enough to make good cut flowers.
- If you cut them too high up the stem the next stems will be shorter.
- If you see buds forming in the node, the stems will not get any longer, so go below these nodes.
To get more flowers from single stem sunflowers here’s how to prune them:
- This will yield up to four flowers that will be smaller than if you stay with a single stem
- When the plant is about 18 in. tall, cut the single stem at a node
- The cut node and the next node down will each generate two new stems; and they’ll be thinner.
Cut in the morning before the heat and sun hits them. Place in a bucket of lukewarm water and bring into a cool darkish place to condition them. This gives you the longest vase life.
Extra info on harvesting sunflowers
When flowers bloom, they (hopefully) get pollinated and start the process of forming seeds. This makes the plant slow down flower production. To prevent your sunflowers from slowing down, harvest all your flowers when they’re ready, don’t let any “go to seed”. So that means you need to keep on it and enjoy all your flowers!
My favorite varieties of sunflowers
One of my favorite sunflowers is ‘Soraya’. It’s a classic-looking sunflower with a dark disk and golden petals. It’s days to maturity are 85-95, so good to start this one early in cells. It is nearly pollenless, and it can produce many flowers.
The other top choice for me is ‘Rouge Royale’, a pollenless sunflower that is a deep, dark burgundy color that’s a delightful addition to bouquets. Days to maturity are 55-65, letting you start them early and sow a second time directly in the garden for a very long harvest.
Some varieties are good for multi-branching, giving many smaller but long-stemmed flowers. ‘Autumn Beauty’ is a nice variety for that and each flower has a variety of fall colors on it. Good if you have space.
Sources for sunflower seeds
One of my favorite sources has always been Johnny’s Seeds
But I now have a new favorite, Sunflower Selections, which carries nothing but a huge selection of sunflower seeds for all purposes, especially sunflowers for cut flowers!
Flowers to go with sunflowers
Classic flowers that last long in the vase, easy to grow, and bloom all season long.
Add these dramatic flowers to your summer bouquets.
Easy to grow, lasts long in a vase, an excellent cutting flower.
These are hard to find…but when you spot them, get them. Long-lasting in the vase, easy, tall.
Papery, colorful bracts of flowers, a great bouquet filler, on it’s own, and excellent for drying.
Tall annual with fine, very fragrant foliage makes this a perfect bouquet filler.