In late spring and summer, you may notice frothy white blobs on the stems of your lavender bushes and other plants. This is known as cuckoo spit, but you'll find it has very little to do with the bird.
What is cuckoo spit?
Cuckoo spit is made by the common meadow spittlebug (Philaenus spumarius), the nymph stage of the froghopper. While feeding on a plant stem, the nymph forces air into fluid from its anus to make bubbles. It then cocoons itself in the bubbles to protect itself from predators, to prevent drying out and to create its own micro-climate. While cocooned it transforms into its adult form – the froghopper.
Why is it called cuckoo spit?
Cuckoo spit has very little to do with the cuckoo, apart from the fact that you're likely to start seeing it at the same the cuckoo arrives in the UK in spring.
What plants does cuckoo spit appear on?
You'll find cuckoo spit on lavender, rosemary, fuchsias, dahlias, roses and many other plants in your garden.
Does cuckoo spit harm my plants?
According to the Royal Horticultural Society, cuckoo spit has little detrimental effect on your plants, so should be tolerated as part of the biodiversity that gardens support. They are not considered to be a pest.
If you think the blobs are unsightly, they can be wiped off by hand or removed with a jet of water from a garden hose. There's no need to use an insecticide.