Perennial—Usually means a plant of which the top portion dies each winter and regrows the following spring; however, some keep their leaves year-round.
Perlite—Mineral used in container-soil mixes. It is very lightweight, white, porous, granular, and used for loosening and allowing more air into the soil.
pH—Abbreviation describing the acidity or alkalinity of soil or water, 7 being neutral, less than 7 being acid, greater than 7 being alkaline.
Pick pruning—Selectively removing limbs and branches rather than shearing.
Pleaching—The interweaving and plaiting together of plant branches. After this training method, subsequent pruning maintains a neat, somewhat formal pattern.
Pollinate- To hand-pollinate take the male flower, peel the petals back and dab the center parts on the female flowers that are still attached to the plant. Female flowers are the ones that have the swollen structures behind the flowers.
Pyrethrum—A natural insecticide derived from the pyrethrum flower or painted daisy, a variety of chrysanthemum.