Turfgrass Management Terms P

Palea - inner of the 2 bracts of a grass floret

Part shade – four to six hours of sun each day. This is similar to part sun, but emphasizes the plant's need for sufficient shade. Part-shade plants also do well in areas with filtered or dappled shade all day

Part sun – four to six hours of direct sun each day. Similar to part shade, this is used to emphasize the plant's need for sufficient sun. Part-sun plants often prefer morning and evening sun

Patch diseases - group of fungal diseases that attack lawns, particularly those that suffer from excessive thatch, poor soil or too much or too little nitrogen. Patch diseases typically show up as rings or semicircles of dead grass. Brown patch comes from the Rhizoctonia solani fungus. It can attack a wide variety of grasses, usually in wet and hot mid-summer conditions. Summer patch comes from the Magnaporthe poae fungus. Patch diseases are best prevented by correcting poor cultural practices. Treatment may include overseeding, fungicide, and amending the soil to correct imbalances

Patches - irregularly shaped areas of damage greater than 4” in diameter and caused by a turfgrass disorder

Pathogen - organism causing disease

Peat - unconsolidated soil material consisting largely of undecomposed or only slightly decomposed organic matter accumulated under conditions of excess moisture

Pedicel - stalk of a spikelet

Perennial – plant that naturally takes more than two years to complete its lifecycle. When grown within their hardiness zones, healthy perennials return on their own year after year, for several years. Grown outside their hardiness zones, they act like annuals and may die each year and not return 

Perennial grasses - lasting or continuing from year to year in areas where adapted

Permeability - measure of the ease with which air, roots and water penetrate the soil

Pesticide - substance used to control or eliminate undesirable weeds, insects, diseases, or animals that are considered pests. Pesticides that target plants are known as herbicides, while pesticides that target insects or mites are known as insecticides and miticides, respectively

pH - common scale that measures the acidity or alkalinity of a solution. The commonly used pH scale runs from 0 to 14, with acidity at the low end, alkalinity at the high end, with 7 considered neutral. Technically, it is a measure of hydrogen ion in a solution (the letters pH stand for “potential of hydrogen”). Soil pH influences the ability of your grass to access essential nutrients, including those added through fertilizers. Most grasses do best in slightly acidic, near-neutral soil pH

Phenology - branch of science that looks at the relationships between seasonal events. In common practice, that means keeping track of such things as the first bloom of certain plants or the first arrival of migratory birds and using those as the trigger for planting seeds, rather than relying on the calendar

Phytotoxic - harmful to plants

Pilose - soft hairy

Pistil - female reproductive structures of a flower

Plant Growth Regulator (PGR) - chemical that can slow the growth of turfgrass

Plant protectant – application of a pesticide before the outbreak of disease or infestation, usually on grass that has a history of such outbreaks or infestations

Plugging - vegetative propagation of turfgrass by means of plugs or small sod pieces. A method of establishing vegetatively propagated turfgrasses, as well as repairing damaged areas

Plugs - individual grass plants, grown in trays, or small 2- to 4-inch sections of turf containing roots, soil and grass. They are a less expensive way of establishing a lawn or patching a bare spot than full slabs of sod, but more expensive than seed. The recommended spacing between plugs varies based on the grass variety. Fast, spreading grasses warrant wider spacing; slow-growing types are spaced more closely. 

Poa - genus of all bluegrasses. Pratensis is the species name for Kentucky bluegrass. Poa annua is annual bluegrass. There's also Poa trivialis (rough bluegrass) and Poa compressa (Canada bluegrass)

Pole edger (stick edger) - typical edging tool with the cutting head at the end of a pole. Pole edgers provide more maneuverability than heavy walk-behind edgers

Pore space - space between solid soil particles or aggregates that is normally filled with water, air or grass roots

Post-emergent (Postemergence) - describes the time period after a plant germinates and emerges above ground 

Pre-emergent (Preemergence) - describes the time period before a plant germinates and is not visible

Pre-emergent herbicide - herbicide that prevents germinating weed seeds from emerging and taking root. Some pre-emergent products also contain active ingredients that kill weeds after they sprout. Timing is critical: Warm-season (summer) weeds begin to germinate when the soil temperature reaches 55 degrees F. Cool-season (winter) weeds germinate in the fall. The exact timing and the type of herbicide you should apply will depend on your climate and the weed type. Pre-emergent herbicides can harm new grass seedlings and prevent grass seed from germinating, so avoid their use in recently planted areas or areas where you plan to seed

Pregerminated grass seed - advanced grass seeding technique in which grass seeds are moistened to trigger germination before they are planted. Great care must be taken, as the temperature, level of moisture and timing of planting are all crucial to success. When done correctly, pregermination shortens the time needed to establish new seed

Profile, soil - cross-section of soil that shows the layers or horizons lying above the unweathered parent material

Propagation - process of multiplying plants through various means. New plants can be grown from seeds or other methods, such as stem and leaf cuttings or root divisions. 

Pruning - process of using shears or a similar tool to trim, reshape or rejuvenate plants, particularly perennials, shrubs and trees. Proper timing of pruning is important to flowering, plant health and cold tolerance 

Puberulent - dimunitive of pubescent

Pubescent - clothed with soft hairs or down

Pythium blight - highly destructive turfgrass disease that can totally destroy a turfgrass stand in less than 24 hours. Pythium blight most commonly occurs under conditions of high temperature and humidity


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