Slugs, known for their preference to consume old decaying matter and play the role of significant decomposing organisms, will switch to eating almost any plant if their favoured diet isn’t available. These pests can turn into a real headache, especially under cool, wet conditions. Their insatiable appetites become evident when, in large numbers, they are able to wipe out an entire bed of seedlings overnight or tear up mature plants.

What’s more, slugs possess an alarming reproductive rate, potentially giving rise to three generations each year. They can reproduce without mating, and every slug has the potential to produce up to 400 round white eggs annually. One hydrangea enthusiast fed up with these pests feasting on her blooms sought help from fellow gardening fans on the Hydrangeas in the UK Facebook group.

Fal Fal posted: “Heard some said slugs don’t eat hydrangea leaves but when I place my plant outdoors overnight for these two or three days, I found the leaf has been eaten like this.

“I also found many slugs sucking around the pot. Any ways to deter the slugs effectively?

“My tulip leaves also suffered from being made holes even more seriously.”

Although it’s uncommon for slugs to target hydrangea leaves, they have a taste for young hydrangea plants.

The indication of a slug issue is the appearance of ragged edges and holes in the hydrangea foliage.

Despite their reluctance to dine on hydrangeas, preferring decayed organic matter instead, when left with no alternative, they will feast on the leaves, quickly leaving hydrangeas looking rather pitiful.

To combat this nuisance, several group members in the comments section suggested employing eggshells as an effective repellent.

Chantel Henson advised: “You need to make a barrier to deter them, and eggshells are a game-changer. It makes it impossible for them to crawl over it.”

Elizabeth Aiken suggested: “Eggshells on the soil. It’ll be too sharp for them and they won’t get to the plant.”

Kim Brannon pointed out: “The sharp edges of eggshells help as a deterrent, but only when they are clean and dry.”

This eggshell slug deterrent isn’t just for hydrangeas, it works for other plants too in the same way.

Not only do eggshells serve as a slug repellent for hydrangeas, but they also provide the plants with a “calcium boost”. Calcium is crucial for cell wall strength, which ensures that hydrangeas stay “robust and healthy”, as noted by Bryan Clayton, CEO at GreenPal.