Garden Glossary - P
Here you will find a glossary of garden terms that start with the letter P.
- Pad and fan cooling - the use of moistened pads and fans to cool a greenhouse.
- Palmate - hand-shaped, with lobes arising from one point.
- Panicle - a loose-branched flower cluster that blooms from the bottom to top.
- Parasitic - an organism that lives on or in another living organism (the host) and obtains nutrition from the host.
- Parterre - French word meaning 'on the ground'. It refers to an ornamental patterning of beds and paths.
- Passalong plants - hard to find plants that are shared among gardeners.
- Pathogen - a disease-causing organism.
- Patio tree - a plant trained to have a single trunk.
- Peat/peat moss - this is the compressed, preserved remains of dead bog plants. It is rich in nutrients and has a high water retention.
- Pebble tray - grouping potted plants in a shallow, water and pebble-filled tray, to maintain humidity.
- Pegging down - increasing flower production on roses by spreading the runners and fastening them to the soil with wire loops.
- Pelletized - the coating and forming into pellets of very small seed so they are easier to handle.
- Pendula - Latin term for weeping plant cultivars.
- Penetration - the point at which a pathogen enters a host.
- Perennial ryegrass - a cool-season turfgrass with seeds that germinate quickly. The cultural requirements are similar to those of Kentucky bluegrass; however, it is not quite as hardy or disease resistant as bluegrasses.
- Perennials - plants that do not die after flowering, but live from year to year.
- Pergola - a structure with parallel colonnades supporting an open roof, similar to an arbor or trellis.
- Perianth - the floral structure, consisting of the calyx and corolla.
- Perlite - porous, hard, white granules of a treated volcanic rock mineral, used in potting soil to improve drainage and aid in moisture retention.
- Persicifolia - Latin term which means having leaves shaped like a peach.
- Pest - any insect or animal which is detrimental to the health and well-being of plants or other animals.
- Pesticide - any substance used to control or kill pests.
- Petals - a whorl of structures that surround the inner reproductive organs of a flower. Together they are called the corolla. They often attract insects by color or nectar, facilitating pollination.
- Petiole - the stalk that attaches a leaf to a stem.
- pH - abbreviation for 'potential of Hydrogen'. The pH of soil is a measurement of the concentration of hydrogen ions.
- Pheromone - a chemical substance that convey information to and produce specific responses in certain animals.
- Phloem - the part of the vascular system taht moves food through the plant.
- Phosphorus - one of the three macronutrients needed by plants. Phosphorus is used to promote root growth, root branching, stem growth, flowering, fruiting, seed formation and maturation.
- Photoperiodism - responses of plants to the relative lengths of light and dark cycles.
- Photosynthesis - the internal process in which a plant turns sunlight into growing energy.
- Phototropism - the bending of a plant toward the direction of more intense light.
- Phytogenetics - the study of plant genetics and breeding.
- Phytopathology - the study of plant diseases.
- Picotee - a flower that has petals edged with a contrasting, usually darker, color.
- Pinch - breaking off the terminal growing point of a plant to encourage axillary buds to grow.
- Pinnate - a series of leaflets arranged on either side of a central stalk.
- Pistil - the female part of the flower, consisting of one or more carpels and enclosed ovules.
- Pollard - a tree cut back to the trunk to make a dense cluster of branches and foliage.
- Pollen - the microspores that carry the male gametophyte of seed plants.
- Pollination - the transfer of pollen from the anther to the stigma.
- Pollinator - an insect or other vehicle by which pollen is carried from one flower to another. A plant that provides for a self-infertile plant.
- Post-emergent herbicide - a pesticide that kills plants after they have grown to seedling stage or beyond.
- Potpourri - a mixture of dried flower petals with herbs and spices used for its fragrance.
- Potting medium - material used for growing plants in containers. Mixes may include vermiculite, perlite, sand, peat, charcoal, loam and fertilizer.
- Pre-emergent herbicide - a pesticide that kills plants as they germinate.
- Primocanes - on raspberries and blackberries, new, first-year canes.
- Procumbent - having stems that trail along the surface.
- Propogation - to increase the number of plants by sexual or asexual means.
- Protozoans - organisms made up of a single cell or a group of basically identical cells.
- Prune - to cut back parts of plants for better shape, disease control or improved fruiting.
- Pupa - a stage in complete metamorphosis when an insect transforms from the larval to adult stage of development.
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