How to Grow Sunflowers, Big or Small Blooms?

by Lisa Mason Ziegler | February 16, 2019

A load of ProCut Orange sunflowers heading to a commercial customer.

Did you know that you control the size of the flower heads on the sunflowers you grow? Interested in growing a gigantic sunflower for the birds to feast on or the perfect smaller head for a bouquet? You can and it is easy to boot.

Our Sunflower Seed Collection can be grown for cut flowers or for bees and birds. It includes 5 varieties, blooming in the photo are Sunbright and Moulin Rouge.

First, a quick lesson on the sunflower. There is no shortage of bloom color variations and petal shapes in sunflowers. Each year brings a new sunflower– some worthy, others not so much.

For our discussion there are two different types of sunflower growth habits. The first is the most common and widely recognized single stem sunflower. A one-stem plant that produces one sunflower bloom and that’s it, done. The second type is the branching sunflower, it will grow into a plant with many branches. Each branch sporting a bloom with less stem strength as a cut flower and takes more growing space in the garden. However, these are the favorites of birds.

Rouge Royale is a branching sunflower that the bees enjoy–but the birds love because it produces black oil sunflower seeds.

Both types are equally as easy to grow and beautiful, but it’s the single stem that the bloom size can be manipulated and produces the best cut flowers. Planting a few every couple of weeks in your garden will supply blooms all season.

Sunbrights covered in our neighbors honey bees.

Within the single-stemmed varieties, I will take it one step further and call out another division. There are a few single-stemmed sunflowers that are known as garden “giants”, grown not for cut flowers but for ornamental and seed production reasons. The steps listed below for making blooms bigger or smaller are also true for this group–however, they do not make suitable cut flowers. And they grow over 12 feet tall and with heads that are huge. Really fun to grow.

A Mammoth Sunflower head mature with seeds shown next to a five gallon bucket for the whopper effect!

So, after all this drilling down–we are still left with a boatload of sunflowers to choose from. All sunflowers enjoy the same growing conditions:

Full sun (at least 8 hours)
Organic rich soil (add compost generously at planting)
Plant 2 week old seedlings in the garden or plant seeds in the garden
Add dry organic fertilizer at planting
Use liquid organic fertilizer weekly while watering
Water generously in dry conditions

One of our weekly production beds planted 6″ apart in all directions to produce the perfect bouquet sunflower head.

The Determining Factor for Bloom Size: it’s how close or far apart you plant them. It’s all about the spacing once you give them the sun and food they need. Remembering that sunflowers are like teenage boys; thinking about their next meal always and they’d like a little water to wash it down. They can’t help but grow big, strong, and beautiful when you give them what they want.

If you are growing for the biggest sunflower you can possibly get, space plants 24” apart in all directions. Whopper blooms will be forthcoming.
If you want the perfect size bouquet sunflowers for the vase (3-5” blooms) than plant 6” apart in all directions.
Spacing plants in between these two extreme examples produces medium size blooms.

A sea of our bouquet size ProCut Orange blooms waiting in line to be made into a bouquet–every flowers dream!

It’s really that simple. For the best cut flowers another note is to select a variety that is pollenless. This will greatly increase vase life and prevent the dropping of yellow pollen onto tabletops. As a bonus, these flowers still produce nectar for pollinators.

Single-stem pollenless favorites from the ProCut Series: Orange, Orange Excel, Horizon, Brilliance, Bicolor, Gold Lite, Red-Lemon Bicolor, Plum, Red, White Nite, White Lite, Lemon, TGW ProCut Mix, TGW Procut Fall Medley Mix, and TGW ProCut Bouquet Mix.