Transition Farm Field Notes - The Story Behind Our Zinnia Breeding – Part II: Learning to Breed Zinnias

Mead - Transition Farm developed Zinnia 2025

Learning How To Breed Zinnias 

Compared to vegetable breeding and seed production, we struggled to find information about flower breeding. We found an online copy of Flower Breeding and Genetics, edited by Neil O. Anderson, and searched it for anything that might help our project. Just as valuable, however, were the small-scale breeders who were generously sharing their own work online. Erin Benzakein from Floret, Kori Hargreave from Dawn Creek Farm, and Tiffany Jones from Blooma Flowers Farm, whose Zinnia Breeder Handbook was published in 2022, all inspired us.

From hand pollination with known varieties, we began to focus our breeding not only on colour but also on the form and size of the flowers.  I was really attracted to fully double or dahlia like zinnias.  Because environmental conditions can influence the expression of doubleness, we decided to select strongly for fully double flowers generation after generation.

For several years we saw steady improvements in colour and form, but we were producing very little seed.

Enter THE FLIES!

Our first idea had been bees. Fluffy bumble bees are not available on mainland Australia, and European honey bees absolutely hated being enclosed, no matter how many diverse nectar and pollen sources we provided. The experiment was a complete failure—for both the bees and us!

A Landline episode interviewed a Tasmanian brassica seed grower. He described hanging roadkill to breed maggots, which then developed into flies that pollinated his isolated brassica seed crops. Flies were also being used successfully in onion and carrot seed production. Maybe flies would work for flowers too.

It all sounds easy but in reality, it took us a whole season to work out how to not let the maggots be eaten by ants or cooked in our intense heat days or escape.  Instead of producing a handful of seed, we were suddenly producing enough to grow much larger breeding populations. Larger populations meant better selection—not only for colour and form, but also for stem length and vigour.

Selection was ruthless. Peter often finished the season by mowing down more than 800 feet of zinnias that didn't make the cut.

After six years of selection, we're now preparing to release the first three zinnia varieties bred here at Transition Farm.

BLUSHING NYMPH

MEAD

VIOLET BLUSH

Why haven't we released them yet?

We are more confident about vegetable breeding than we are about flower breeding. Although this will not be our first Transition Farm-developed flower variety, these zinnias have generated so much anticipation that we want to ensure they are truly ready before releasing them.

We have found side-by-side variety trials to be an essential part of being both vegetable and flower growers.

Over the past few years we've grown many of the newest releases alongside our own breeding lines. Those trials have shown us just how much variation can still exist within recently released open-pollinated zinnias. That's not necessarily a flaw—genetic diversity is one of the things we love—but it does reinforce the importance of understanding exactly what growers can expect.

Sharing these flowers is exactly what we have been working towards for the past six years. We really want everyone who grows them to be as delighted with them as we are.

And we have so many more varieties in development. This is only the beginning.