Dahlias, celebrated for their vibrant blooms and diverse forms, are a popular choice in many gardens, often providing color from midsummer until the first frost. Gardeners frequently wonder about their role in supporting local ecosystems, particularly regarding pollinators. While dahlias are generally seen as beautiful additions, their effectiveness in attracting beneficial insects is not a simple matter.
Dahlias and Pollinators: The Connection
The ability of a dahlia to attract pollinators largely depends on its flower form. Many modern dahlia hybrids feature densely packed petals, which can obscure or completely block access to the flower’s central disk where pollen and nectar are located. This makes it difficult for bees, butterflies, and other pollinators to reach their food source. Varieties with open centers, however, offer easy access to these resources.
Dahlias with numerous layers of florets often lack an accessible central disk, providing no food for foraging insects. In contrast, dahlias with visible central disks are a valuable food source, especially late in the season.
Dahlia Varieties That Attract Pollinators
Certain dahlia varieties are particularly effective at attracting pollinators due to their open flower structures. Single-flowered dahlias, for instance, have a single row of petals surrounding a prominent, accessible center, making them ideal for bees and butterflies seeking pollen and nectar. Examples include varieties like ‘Bishop of Llandaff’ and those from the ‘Happy Single’ series.
Anemone-flowered dahlias also feature an open structure, with a central cushion of smaller, tubular florets surrounded by one or more rows of flat petals, offering easy access to pollinators. Similarly, collarette dahlias have a distinctive “collar” of shorter petals around an open center, providing an inviting landing pad for insects. Some dinnerplate dahlias, despite their large size and many petals, can also become pollinator-friendly as their centers open up a few days after blooming, revealing pollen.
Maximizing Pollinator Visits to Your Dahlias
To encourage more pollinators to visit your dahlia display, select the appropriate varieties with open centers. Planting dahlias in sunny locations with well-draining soil supports their healthy growth and bloom production, which in turn attracts more insects. Grouping plants together in masses creates a larger, more visible target for pollinators and provides a more abundant food source.
Avoiding pesticides is also crucial, as these chemicals can harm or kill beneficial insects, disrupting their populations and reducing their ability to pollinate. Providing a shallow water source, such as a bird bath with pebbles for landing, can also attract and support thirsty pollinators.
Why Pollinators Matter
Pollinators are important for the reproduction of nearly 90% of wild flowering plants globally. They contribute significantly to maintaining biodiversity and ecosystem health. Beyond natural environments, pollinators are also important for human food production.
About one-third of the food and drink consumed worldwide relies directly or indirectly on pollinators. More than 75% of the world’s leading crop types benefit from animal pollination, impacting production, yield, and quality. Crops like apples, almonds, and various fruits and vegetables depend heavily on their activity. Without pollinators, global food security and the diversity of essential nutrients in human diets would be significantly impacted.