Dr. A’s Top Picks From California Spring Trials 2025, Day 2

By Allan Armitage|March 27, 2025

The second day of California Spring Trials 2025 is complete. Here are five plant varieties and series that caught my eye when we visited Ball Horticultural on the second day of CAST 2025. Featured breeders include Darwin Perennials, PanAmerican Seed, and Selecta One.

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Dianthus ‘Dart Raspberry Red’ (PanAmerican Seed) | All photos courtesy of Robin Siktberg

The Dart series of dianthus has only been out for a couple of years, but its strong habit, its many flowers, and its compact habit have caught the notice of many growers.

This new raspberry red color caught my eye from across the garden, and all the positive characteristics I just mentioned are present in spades. While it is recommended for containers, it is equally at home in the ground. This color will jump off the bench.
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Heuchera ‘Carnival Lime Zest’ (Darwin Perennials)

Heucheras come and go, actually, they mostly come and stay. And today, we have sufficient coral bells from which to choose. However, one of the most desirable foliage colors is chartreuse/lime. There have been many attempts for a better heuchera in that flavor; all looked good in a container but showed poor vigor in the landscape.

This newest attempt from Darwin caught my eye not because of the foliage, which is quite beautiful, but because of the obvious vigor. This is worth a closer look, and then let’s see if we have a lime green heuchera we can count on.
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Osteospermum ‘4D Pink Lemonade’ (Selecta One)

For me to highlight an osteo is very unusual. I continue to hope they will be tougher and more resilient as the breeders work their magic.

Well, this one certainly caught my eye, and it's an osteo that even I will try in the garden. If osteos are on your greenhouse bench, give this one a try.
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Penstemons Mountain Treats Series (Darwin Perennials)

Penstemons have been a bit of a puzzle in recent years. They are a North American native, they attract a ton of butterflies and other pollinators, but they have not found as strong a presence in American landscapes as they deserve. I applaud the team at Darwin for continuing their breeding work with penstemons. Their three series, the shorter Rock Candy series, the mid-size Mountain Treats, and the taller Summit Sweets series provide a height range and a flowering season for everyone. Numerous colors are available. I hope growers and retailers embrace this old-fashioned plant with its new look.
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Phlox Candy Cloud Series (Darwin Perennials)

Phlox is on everyone’s must-have perennial list. They are favorites of landscapers and gardeners throughout the country. Many species of phlox are grown, from upright summer phlox to compact moss phlox. All are favorites.

The Candy Cloud series is a hybrid of numerous species, one of the strongest being woodland phlox, P. divaricata. That it flowers longer than woodland phlox, tolerates more sun, and still performs well in shady conditions potentially makes this series a winner.

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Dianthus ‘Dart Raspberry Red’ (PanAmerican Seed)

The Dart series of dianthus has only been out for a couple of years, but its strong habit, its many flowers, and its compact habit have caught the notice of many growers.

This new raspberry red color caught my eye from across the garden, and all the positive characteristics I just mentioned are present in spades. While it is recommended for containers, it is equally at home in the ground. This color will jump off the bench.

Heuchera ‘Carnival Lime Zest’ (Darwin Perennials)

Heucheras come and go, actually, they mostly come and stay. And today, we have sufficient coral bells from which to choose. However, one of the most desirable foliage colors is chartreuse/lime. There have been many attempts for a better heuchera in that flavor; all looked good in a container but showed poor vigor in the landscape.

This newest attempt from Darwin caught my eye not because of the foliage, which is quite beautiful, but because of the obvious vigor. This is worth a closer look, and then let’s see if we have a lime green heuchera we can count on.

Osteospermum ‘4D Pink Lemonade’ (Selecta One)

For me to highlight an osteo is very unusual. I continue to hope they will be tougher and more resilient as the breeders work their magic.

Well, this one certainly caught my eye, and it’s an osteo that even I will try in the garden. If osteos are on your greenhouse bench, give this one a try.

Penstemons (Darwin Perennials)

Penstemons have been a bit of a puzzle in recent years. They are a North American native, they attract a ton of butterflies and other pollinators, but they have not found as strong a presence in American landscapes as they deserve. I applaud the team at Darwin for continuing their breeding work with penstemons. Their three series, the shorter Rock Candy series, the mid-size Mountain Treats, and the taller Summit Sweets series provide a height range and a flowering season for everyone. Numerous colors are available. I hope growers and retailers embrace this old-fashioned plant with its new look.

Phlox Candy Cloud Series (Darwin Perennials)

Phlox is on everyone’s must-have perennial list. They are favorites of landscapers and gardeners throughout the country. Many species of phlox are grown, from upright summer phlox to compact moss phlox. All are favorites.

The Candy Cloud series is a hybrid of numerous species, one of the strongest being woodland phlox, P. divaricata. That it flowers longer than woodland phlox, tolerates more sun, and still performs well in shady conditions potentially makes this series a winner.

Allan Armitage was a professor in the Department of Horticulture at the University of Georgia for 30 years. He recently retired and remains an active consultant, author and lecturer. See all author stories here.