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.
Plant--Add transplants of perennials such as garden mums, aromatic asters (Aster oblongifolius), Mexican mint marigolds (Tagetes lucida), and Mexican bush sages (Salvia leucantha) now for a show of color in your flowerbeds this fall.