Highlights from 2025 Field Trials: Boerner Botanical Gardens

The Proven Winners Surefire Begonia Series. | Boerner Botanical Gardens

(Information provided by Kate Grundle, Trial Garden Horticulturalist)

This season was very hot and very wet. Every month from June onward had above-average precipitation, and the middle of summer brought intense heat. I lost about 20% of the trials overall. The heat really hit the lobelia and calendula hard — the lobelia eventually bounced back, but the calendula didn’t make it through. Interestingly, though, the calendula reseeded itself and came back strong from seed later in the season. On the upside, the frequent rain made things a lot easier — I barely had to haul a hose out to water the trials.

The Boerner Botanical Gardens in Milwaukee, WI, hosted three concurrent rose trials this year, each with about 150 roses, running on a two-year cycle. Alongside the roses, there were roughly 50 Proven Winners trials and another 50 All-America Selections annual flower trials. Results were mixed, but overall, quite successful. The top performers were the zinnias, kale, verbena, amaranth, and several standout roses.

One noteworthy trend Kate observed was how well compact, small-scale plants performed, especially those that would transition well to containers if the trials were offered to the public. That focus on container-friendly material has become an interesting and consistent theme.

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The biggest challenge — same as last year — was getting everything planted and mulched on time. Fortunately, my incredible volunteers made it happen. Their help really kept us on track and allowed the trials to succeed despite the hectic schedule.

Standout Performers at Milwaukee Boerner Botanical Gardens

The zinnia trial stole the show this year — they just refused to quit blooming and put on a beautiful display all season. My kale trial was also impressive; the purple variety had great color, a whole curly leaf, and showed strong resilience to insect pressure. The kale right next to it wasn’t nearly as lucky — the insects devoured it — so the contrast was striking.

A few of the roses in the second year of the American Garden Rose Selections (AGRS) trial also really stood out for their large flower count, disease resistance, beautiful color, and outstanding fragrance.

The Proven Winners Surefire Begonia Series continues to amaze me. They perform beautifully in both sun and shade, never stop blooming, and look flawless all season. I had to double-check more than once that they weren’t artificial — they’re that good.

For more 2025 field trials information and variety highlights, click here.

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Marisa Reyes is a Content Specialist at Greenhouse Grower. See all author stories here.