Double vs. Single Zinnia Flowers: Which Should You Grow?
If you’ve ever looked at zinnias and wondered why some blooms are packed with petals while others have a wide-open center, you’re looking at the difference between double, semidouble, and single flower forms.
There isn’t really a “best” one. We grow and enjoy all three. The one you reach for most just depends on what you want from your zinnias.
What makes a zinnia double?
A double zinnia has several rows of petals, giving the flower a fuller, more layered look. On a really full double, you may see very little of the center disk at all.
Giant Lime Zinnia Seeds are a good example of the full, layered look we mean when we talk about doubles.
A single zinnia usually has one row of petals surrounding an exposed center. Semidoubles land somewhere in the middle, with extra rows of petals while still leaving part of the center visible.
And this is where zinnias get fun. If you’re growing open-pollinated seed or working with breeding lines, flower form can vary. You may get doubles, semidoubles, and singles showing up among related plants.
Which type do pollinators prefer?
Singles and open-centered blooms have an obvious advantage here. Their pollen and nectar are easier for bees, butterflies, and other pollinators to reach.
Our White Pastel Exposed Breeder’s Pack is a nice example of that open-center form.
That doesn’t mean pollinators completely ignore double flowers, but if attracting pollinators is one of your main goals, adding singles and semidoubles to the garden gives them easier access.
Which type is best for cutting?
This is where doubles tend to steal the show. A full bloom has a lot of presence in a bouquet, and those extra layers of petals can make even a simple handful of zinnias look finished.
Our Pastel Double Mystery Pack is a fun choice if you’re after softer colors and fuller flower forms.
Singles and semidoubles still have a place in the cutting garden, though. We actually like the contrast. A few open-centered flowers mixed among big doubles can keep a bouquet from feeling too heavy or uniform.
Are doubles harder to grow?
Not really. Flower form doesn’t change the basic way we grow zinnias. Give them plenty of sun, good airflow, and room to grow, and both single and double forms can do beautifully.
We wouldn’t choose a variety based on flower form alone if disease resistance or garden performance is your biggest concern. Genetics, growing conditions, spacing, weather, and the individual variety all matter too.
What if you want a little of everything?
Then grow a mix. Honestly, that’s part of what makes a zinnia patch so much fun.
Pastel Lilacs Zinnia Seeds can produce double, semidouble, and single flower forms, so you can see the differences growing right beside one another.
If you save seed, those differences become even more interesting. One plant may be the color you love but have a more open flower. Another may have the petal count you want. Those little differences are exactly the sort of things we pay attention to in our own breeding projects.
So, double or single?
If you love big, full flowers for bouquets, start with doubles. If you want open centers for pollinators, make room for singles and semidoubles. If you’re like us and enjoy seeing what each plant does, grow some of both.
There’s no reason every zinnia in the garden has to look the same. In fact, we think it’s more interesting when they don’t.
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