If you mean well with the bees and buy insect-friendly plants, you can still harm the animals. Because many popular summer flowers have a high pesticide load. This is the result of a study by the Federal Government for the Environment and Nature Conservation Germany (BUND).
22 perennials from garden centers and hardware stores with the label “bee-friendly” were examined for toxic residues. The result: 38 pesticides were found, 5 active ingredients are “highly dangerous” for bees and 7 are not approved in Germany.
Also precarious: According to BUND, 20 pesticides found are also “highly dangerous” for people – those who work in the rearing plantations, gardeners and florists who are in daily contact with the plants are affected.
How do pesticides harm bees?
“Even a few nanograms of substances like the ones we found are harmful to bees and other pollinating insects,” says BUND pesticide expert Corinna Hölzel. The insects suffer functional disorders: bees, for example, can no longer find their way back into their hive, collecting activities or the ability to reproduce are restricted. Or their immune system is weakened.
Why do bee-friendly plants contain these substances?
Pesticides are designed to keep plants healthy by protecting against diseases and pests. The disadvantage is that what destroys pests often also harms beneficial insects.
“More than 80 percent of the bedding and balcony plants on the market come from the Global South,” says BUND expert Corinna Hölzel. Mainly from countries in Latin America and Africa. Production is cheaper there and the climatic conditions for rearing are better. “Thirdly, there is less legislation there, so there are fewer controls – you can use more pesticides, which is good for a quick profit.”
Hobby gardeners cannot recognize the origin. The labels on the plants only say “in which country the last cultivation step was,” says Corinna Hölzel. These are mainly Germany and the Netherlands. Here the small plants are grown, repotted and, if necessary, treated with pesticides again. “But usually it’s not these very violent means,” says Hölzel.
How can plants treated in this way be identified when purchasing?
Not at all, says the BUND expert for pesticides, Corinna Hölzel. There are neither labeling requirements nor limit values. “Even experts cannot see from the plants where they were raised and what kind of production chain they went through.”
But Hölzel names an alternative: “Our main recommendation to consumers are plants with organic seals. These guarantee the non-use of chemical-synthetic pesticides – and this is also checked by an independent body.” The BUND recommends ornamental plants from the well-known organic cultivation associations Demeter, Bioland and Naturland as well as greens with the EU organic seal.
And one should support local nurseries with their own rearing – “ideally also organic nurseries, but they are not available everywhere,” says Corinna Hölzel. Her tip: Ask questions about the origin. “That doesn’t mean that the local nurseries don’t buy anything at the wholesale market. But you can ask and if you get the answer that this is done in your own greenhouse, you can also be sure of it.”
Should I rip out all my recently bought plants?
“It’s always a question of conscience,” answers Corinna Hölzel. “But in terms of resource protection, I wouldn’t recommend anyone to rip out plants that have already been bought and planted and buy something else. What’s in there should stay in there – and then you pay attention to it the next time you buy it.”
The good news is that the toxins break down – even if it can take months or years, depending on the substance, especially once they have penetrated the soil. That’s why Hölzel’s last tip is: pull offshoots from the bee-friendly plants or share perennials that you’ve had in the garden or on the balcony for a long time. You can then use it to go to plant exchanges, for example.