In a recent webinar hosted by Jackson & Perkins and the American Rose Society, Paul Zimmerman, a respected voice in rose care, shared his insights on the crucial role beneficial insects play in maintaining healthy gardens. His practical approach to attracting and sustaining these natural allies offers a sustainable alternative to pesticides, promoting a balanced ecosystem where roses can flourish with minimal intervention.
The Power of Beneficial Insects
https://youtu.be/eLdV22tGf14?si=QP4MWWeXry-9RMBqFor many gardeners, aphids, thrips, and other pests are familiar foes that seem to return season after season. Zimmerman suggests that the key to long-term pest management lies not in chemical sprays but in fostering an environment where natural predators thrive. Beneficial insects such as ladybugs, hoverflies, lacewings, and parasitic wasps can significantly reduce pest populations, but they need the right conditions to stay and reproduce. Watch the original (recorded) Webinar here:
Creating a Host Environment
Zimmerman emphasizes that simply purchasing and releasing beneficial insects is ineffective unless a suitable habitat is available. “If you’ve ever released ladybugs into your garden only to find them gone the next day, it’s because they had no reason to stay,” he explains. To create an inviting environment, gardeners must provide three essential elements: food, water, and shelter.
Water: Clean, chemical-free water sources are vital. Birdbaths, shallow trays, or even small puddles replenished regularly can serve as hydration spots. Zimmerman underscores the importance of ensuring water is accessible but not treated with chemicals, which can deter or harm beneficial insects.
Food: Nectar-rich plants are the foundation of a garden that attracts and sustains beneficial insects. Zimmerman advises gardeners to select a variety of perennials that bloom throughout the growing season. While specific plant recommendations will vary by region, he encourages local research to identify what attracts predatory insects in the area. “Go to Jackson & Perkins, find perennials that bloom from spring through fall, and plant them directly in your rose garden,” he advises. Integrating these plants among the roses, rather than separating them, ensures that beneficial insects remain close to their prey. Additionally, planting for beneficial insects naturally supports pollinators like bees and butterflies, creating a thriving and diverse garden ecosystem.
Shelter: Shelter can take many forms, from the foliage of perennial plants to piles of branches or ornamental grasses. Zimmerman strongly advocates against cutting back perennials in the fall. “Leaving rough foliage provides overwintering spots for beneficial insects,” he notes, pointing to butterfly bushes and other shrubs as prime examples. Hollow-stemmed plants, such as echinacea, agastache, and penstemon, are particularly valuable, as insects like native bees and solitary wasps may lay their eggs inside the stems. This dual-purpose approach benefits pollinators as well, ensuring your garden is teeming with life from early spring to late fall.
Birds as Natural Pest Control
Beyond insects, Zimmerman highlights the role of birds in pest management. Birds feed on various garden pests, including Japanese beetles and aphids. “Hang bird feeders, provide bird baths, and attract local species that will naturally contribute to pest control,” he recommends. Diane Sommers, President of the American Rose Society, shared her experience of sparrows in her garden eating Japanese beetles directly off her rose bushes.
Embracing Imperfection
A recurring theme throughout Zimmerman’s talk is the acceptance of minor pest damage as part of a healthy, functioning garden ecosystem. “Nature isn’t perfect, and a little insect damage is a sign that your garden is supporting life,” he explains. By tolerating small populations of pests early in the season, gardeners can ensure that predatory insects have enough food to sustain their populations, leading to more effective pest control as the season progresses. This approach often benefits pollinators as well, as flowering plants are left intact to provide continuous nectar sources.
Reverse Engineering Pest Management
Zimmerman introduces a simple but powerful method for addressing pest issues: reverse engineering. Start by identifying the common pests in your area. Next, research which beneficial insects naturally prey on these pests and determine what plants and conditions those predators prefer. This localized approach ensures that the insects drawn to your garden are already adapted to the region. Zimmerman advises consulting local agricultural extension offices, universities, and master gardeners for tailored advice. Lacewings, ground beetles, and tachinid flies are just a few more beneficials to consider, each contributing to pest control and pollination efforts.
The Challenge of Japanese Beetles
One of the most persistent challenges for rose growers is Japanese beetles. Unlike aphids or thrips, Japanese beetles lack many natural predators. Zimmerman suggests a multi-faceted approach:
- Use BTG (Bacillus thuringiensis galleriae) to target beetle larvae in lawns and garden beds. This biological control is specific to beetles and safe for other insects.
- Encourage birds, such as sparrows, to feed on adult beetles.
- Regularly prune and clean the garden to disrupt beetle-attracting signals emitted by damaged roses.
- Physically remove beetles by hand and place them in soapy water, a simple but effective method endorsed by researchers.
A Sustainable Future for Rose Gardens
By embracing the principles of integrated pest management and creating environments that attract beneficial insects, gardeners can reduce their reliance on chemical solutions and cultivate healthier, more resilient gardens. As Zimmerman concludes, “The entire process takes time, but nature will find its balance. With a little patience, the rewards will bloom beautifully.”
For those eager to dive deeper, Zimmerman’s full webinar, along with past and future sessions, can be found through the American Rose Society and Jackson & Perkins. These resources offer valuable guidance for rose enthusiasts at all levels, reinforcing the joy and satisfaction that comes with nurturing a vibrant garden ecosystem.
Paul Zimmerman is the founder of Paul Zimmerman Roses, dedicated to the philosophy that “Roses Are Plants, Too.” With decades of hands-on experience, Paul specializes in all kinds of roses but particularly antique, shrub, and David Austin roses. A sought-after designer, consultant and educator, he designs sustainable rose gardens for private clients and public institutions both in person and virtually
