What’s Happening Here?
This week’s challenge is on hydrangea, which is typically marketed as a woody ornamental, but by definition is still considered a perennial. I haven’t found hydrangea to be difficult to grow, however, there are a few problems I’ve seen on them during production in the past. Is this one of them?
I came across this crop of Hydrangea paniculata last week while visiting growers in Ontario, Canada. Fall can be a challenging time of year to remain objective and can be difficult for some growers to look beyond the transitional fall appearance many plants go through as the season progresses. I had to ask myself, “Is this appearance normal for hydrangea this time of year?”
My answer was, “No, there's something else going on.” The pattern wasn't uniform across the crop (not shown in the picture above). The color differences would appear more uniform across the crop with fall transitions; this crop appeared patchy. You can see the foliage appearance is a little off.
Is this enough for you to diagnose the cause of the off-colored foliage? Is this normal fall transition or is something else ailing these plants? It’s time for me to ask, “What’s happening here?” I’ll reveal the answer below. Good luck!
Monrovia's Top 10
I shared numerous great-looking perennials from the Breeder Showcase during Monrovia’s 100th Anniversary Centennial Celebration held at their facility near Portland, Oregon, in a newsletter last month. The trials featured over 400 perennial and shrub varieties, and attendees like me were asked to place flags in the top three varieties that caught their eye. The results have been tallied and here are the Top 10 plants from the 2026 Breeder Showcase at Monrovia.
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Actaea Pink Spike
Monrovia exclusive
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Andropogon Black Stallion
Intrinsic Perennials
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Echinacea SunMagic Vintage Hot Red
Bull Genetics
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Echinacea SunMagic Chocolate Cherry
Bull Genetics
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Echinacea SunMagic Double Hot Pink
Bull Genetics
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Hydrangea paniculata Little Spooky
Concept Plants
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Heuchera Fyre Wing Amber
Terra Nova Nurseries
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Hydrangea macrophylla Centennial Ruby
Monrovia exclusive
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Lavandula angustifolia La Diva Vintage Amethyst
Dümmen Orange
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Sedum Hot Rocks Dark Leaf Red
Syngenta Flowers
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I personally visited the Breeder Showcase and saw firsthand how many great new varieties were being trialed. Trust me when I say there were dozens and dozens of plants worthy of making the Top 10. I showcased a whopping 36 of them in the September 19, 2026 edition of Perennial Pulse. Please go back and see if you agree with me.
50k to Grow 50k
Seed Your Future has a new fundraising campaign aimed to raise $50,000 by December 31, 2026 to bring free career exploration resources to educators and students nationwide. This initiative is aimed to help at least 50,000 young people discover the opportunities available in horticulture.
Seed Your Future is a national movement dedicated to inspiring the next generation of plant professionals. Since 2014, this movement has worked to change perceptions of the horticulture industry and make career pathways more visible to students and educators.
How Your Gift Grows
Every donation helps Seed Your Future expand access to career exploration resources, and connect more educators and students with horticulture. Contributions can help support:
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$85 equips 10 teachers with career exploration tools
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$250 provides plantable career exploration papers for career fairs
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$500 impacts 2,000 students exploring horticulture careers
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$1,000 empowers more than 115 educators with career pathway resources
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$5,000 covers the cost of two high school educators attending Seed to STEM immersive program
Each educator reached is a chance to introduce students to careers they may not encounter through traditional classroom learning. From hands-on growing and plant science to business, design and emerging technologies, horticulture offers a wide range of possibilities for the next generation.
How to Support
Individuals, companies and industry partners can support the campaign through personal donations, corporate contributions or introductions to others who want to invest in the future of horticulture. All gifts made by December 31 count toward the $50,000 goal and are tax-deductible as allowed by law.
Thank you in advance for your consideration.
The Answer is ...
I shared this image of a crop of Hydrangea paniculata at the top of the newsletter and challenged you to correctly determine what was causing the leaves to appear off-color. As good as phone cameras are these days, it still may be difficult to determine what’s ailing these plants from this distance. Let’s take a closer look:
A closer look at the upper leave surfaces reveals there's a large amount of tiny speckles or stippling on the leave surface. The lightbulb probably lit up right then and many of you probably confirmed and locked in your answer.
To verify, most growers will go further and look at the undersides of the leaves (image on the right) and, voilà, there they are. Spider mites. They still may be hard to see in this image, but trust me, they're there. If your final answer was two-spotted spider mites, you correctly solved this week’s challenge.
Pacific Northwest Pest Management Handbooks
While looking for articles or data on managing spider mites I could pass along to go with this week’s diagnostic challenge, I came across a pretty good resource from Pacific Northwest Pest Management Handbooks outlining spider mites and how to manage them.
The website provides a list of natural enemies, as well as a comprehensive listing of both chemicals and non-chemical control options. I invite you to check out this resource.
Greenhouse Ornamental Pests
In you liked what you saw in the Pacific Northwest Pest Management Handbooks spider mite webpage above, consider checking out all their other pest resource pages:
I hope you find these links useful.
My email is paul@pace49.com if you have any comments, article suggestions or if you'd just like to say hello.
Best regards,
Paul Pilon
Editor-at-Large—Perennial Pulse
National Sales Manager—Pace 49, Inc.
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