A number that is calculated to summarise a group of numbers. The most commonly used average is the mean, the sum of the numbers divided by however many numbers there are in the group. The median is the middle value in a group of numbers ranked in order of size.
Perennials: cutting back. Perennials are not demanding plants, but trimming them after flowering finishes in autumn helps improve their appearance and flowering. However, you can leave some stems over winter to provide homes and food for wildlife, and then trim back in spring.utting back herbaceous perennials during autumn restores order and tidiness to the garden. However, this removes potential winter interest, in the form of height and structure, plus food and habitat sources for wildlife.
While setting up a garden of herbaceous perennials, you should ensure that the plant you are going to cultivate is ideal for the site you selected. Stem of herbaceous plant is green and fleshy and it does not have woody tissue. In comparison to woody plants, it has a covering of thin epidermis. Woody plants also have a bark. Herbaceous stem has more pith and it doesnât have cambium. Due to this, the height of these stems may increase but the diameter remains small.