Ecological balance in the garden: The power of wildflowers

At a glance

• Wildflowers form the basis for trophic cascades – the food chains that extend all the way up to predators.
• Targeted food sources in July prevent the collapse of beneficial insect populations after the first flowering period.
• Species like the cream pincushion (Scabiosa ochroleuca) act as essential hubs within the network.

Trophic cascades and the ecological balance in the garden

In July, when the midsummer heat defines the garden, the stability of the ecological balance is put to the test. Many gardeners view plants merely as decorative elements. From a biological perspective, however, wildflowers are the primary producers in a trophic cascade—a sequence of dependencies where energy flows from the plant to the herbivore and then to the predator.

By encouraging native species in your garden, you are doing more than just creating a sea of flowers; you are establishing a complex food web. The cream pincushion (Scabiosa ochroleuca) is an excellent example of this. As a specialist for nutrient-poor, dry sites, it not only provides nectar for long-tongued insects but also serves as a host plant for highly specialised larval stages. If these specific food plants are missing, pollinators will move on, which in turn leads to the loss of the beneficial insects that rely on them for food.

The stages of the cascade at a glance

4 steps to promoting stable populations

1. Create climatic buffers: Leave a portion of your garden unmown in July. Tall vegetation reduces evaporation from the soil and protects ground-dwelling insects, such as the wood ground beetle ([Carabus nemoralis]), from overheating.
2. Increase connectivity: Plant Scabiosa ochroleuca in small groups. Close proximity minimises the energy expenditure for pollinators while foraging.
3. Avoid chemical intervention: Pesticides immediately disrupt trophic cascades. If you remove pests like the green peach aphid ([Myzus persicae]) using insecticides, you deprive the larvae of lacewings ([Chrysopidae]) of their livelihood.
4. Promote structural diversity: Integrate deadwood or stone piles. These provide retreats for predators that regulate pest dynamics throughout July.

The goal is not the total absence of so-called pests, but rather a balance in which the presence of predators like the seven-spot ladybird ([Coccinella septempunctata]) keeps herbivore numbers below the threshold of economic damage.

Frequently asked questions

Why is the choice of native plants so important?

Native plants are adapted through co-evolution with local insects. This is the only way for larvae and specialised pollinators to find the food they require.

What is a trophic cascade?

It is the transfer of energy along a food chain from the plant to the herbivore and up to the predator (e.g., birds or predatory insects).

Should I fertilise the lawn in July?

No. Fertilisation promotes aggressive, fast-growing grasses and crowds out the species-rich wild flora that is essential for ecological balance.

Main article: Wildflowers in July: 5 species for a biodiverse insect paradise