Cucumber plants are vines and in the wild they are meant to climb up objects in order to take the best advantage of sun exposure. The higher up a cucumber plant can climb, the less likely it is that they will compete with other plants for sunshine. In order to do this, cucumber plants have evolved with a system where specially developed leaves are sensitive to touch. These leaves curl around whatever it is that they touch. This allows the plant to literally pull itself up over obstacles for light.

In the modern garden, cucumber plants are frequently grown on the ground without any surrounding supports. Because of this, many people don’t realize that a cucumber plant’s natural instinct is to climb. Modern gardeners may not realize that the tendrils on a cucumber are natural.

Read more at Gardening Know How: Lasciare attaccati i viticci delle piante di cetriolo https://www.gardeningknowhow.com/edible/vegetables/cucumber/leave-cucumber-plant-tendrils-attached.htm