Glossary of Terms – ‘P’ WORDS
Word or Term
Definition
Pad and Fan
Cooling
Palmate
The use of a moistened surface and fans to cool
a greenhouse.
Hand shaped, often with fingers or lobes (five or
more), arising from one point. A pattern of
compound leaflets or leaf venation, with
elements radiating from a central point.
Botanical Latin term meaning from the Western
US or near the Pacific ocean.
A loose branched flower cluster of racemes or
corymbs that begins blooming at the bottom,
with uppermost flowers blooming later. The
cluster does not end in a terminal flower.
Almost exclusively in monocot leaves, a pattern
in which all veins run approximately parallel to
each other, either from the base of the leaf or
from the midrib to the margin.
Any plant that grows upon another. It steals its
moisture and nourishment from its host. This
often results in declined vigour or death of the
host plant.
Botanical Latin prefix meaning small or reduced.
Botanical Latin term meaning having smaller
flowers.
Botanical Latin term meaning having smaller or
shorter leaves.
Plants that are shared between friends and not
easily found in catalogues.
An organism (mostly virus or fungus) causing a
plant disease.
The preserved and compressed remains of dead
bog plants or moss, rich in nutrients and with a
high water retention. Commonly used as a soil
amendment, peat tends to add to the acidity of
the soil pH. It is free from weeds and disease.
Often known as peat moss because it is from
sphagnum or sedge.
Grouping potted plants within a shallow, water
and pebble filled tray in order to maintain
humidity in an environment with central
heating. Water is poured into the pebbles as
needed and evaporates up and around the
plants.
Said of a leaf with the lateral lobes cleft into two
or more segments.
Stalk of an individual flower in an inflorescence.
The main flowering stalk of a plant.
Describes a plant or plant part that hangs freely
(vertically) from a point below its attachment.
Pacifica/Pacificum
/Pacificus
Panicle
Parallel venation
Parasite/Parasitic
Plant
ParviParviflora
Parvifolia
Passalong Plants
Pathogen
Peat/Peat Moss
Pebble Tray
Pedate
Pedicel
Peduncle
Pendant
Also see.....
Pendula/Pendulum Botanical Latin term for a weeping (or
/Pendulus
sometimes just spreading) cultivar.
Perennials
Plants that live for more than one growing
season, three years or more under normal
conditions. The length and severity of the
winter, particularly how deep the ground
freezes, is the prime factor in determining what
plants are perennials. There are two types of
perennials:
Herbaceous perennials usually flower and set
seed in spring and summer then die to the
ground at the end of the growing season but
send up new shoots the following spring.
Woody perennials, such as trees and shrubs, do
not die back to the ground but get larger each
year. Perennials usually produce one flower crop
each year, lasting anywhere from a week to a
month or longer. It is generally grown as a
nearly permanent fixture in a garden and
typically grows as a clump that expands outward
through time, (either by runners or re-seeding
to self propagate).
New perennials are typically made by dividing
the clumps though some grow easily from
seeds. Dividing clumps creates new plants and
helps keep the old clump growing and flowering
vigorously. Perennials can be obtained from
garden centres and by mail order. Choose the
species, variety and colour carefully since they
are more expensive than annuals and are
replaced less often. It is a common practice to
grow annuals and perennials together to provide
color throughout the growing season. Another
strategy is to grow a variety of perennials with
different blooming seasons.
Perfect Flowers
Perfoliate
Perianth
Periderm
Perlite
Flowers with both stamens (male) and a pistil
(female), but lacking either sepals and/or
petals.
Leaves in opposite pairs, the base of each one
broad and completely united to the base of the
opposite leaf such that the two leaves appear as
if they were a single leaf with the stem coming
up through the middle.
The floral envelope or structure, consisting of
the calyx and corolla (when present), especially
when the two whorls are fused.
Technical term for bark; it consists of cork, cork
cambium, and any enclosed tissues such as
secondary phloem.
Porous, hard white granules of a treated
volcanic rock mineral, usually mixed with potting
Persicifolia
Pest
Pesticide
Petal
Petaloid
Petiole
pH Level
Phenotype
Photoperiodism
soil to improve drainage and promote moisture
retention. The treatment begins when the
mineral, expanded to 7-15 times its original
volume by a heating process, forms the light
granules. When added to soil perlite reduces the
weight of the soil, a point of great benefit when
dealing with very large containers. There is,
however, no nutrient value.
Botanical Latin term meaning having leaves (folia) shaped like the peach (Prunus persica).
Any insect or animal which is detrimental to the
health and well being of plants or other animals.
Any substance used to control or kill pests such
as insects, weeds, birds, mammals, fish, or
microbes.
The second in a series of four rings or whorls
that make up a typical flower. In the outermost
whorl are the sepals (protective and leaf-like).
Then come the petals, stamens to produce
pollen, and, at the centre, an ovary made of
carpels (often referred to as the pistils).
Resembling a flower petal. Parts of plants that
may have petaloid characteristics include bracts,
sepals and stamens.
The stalk that attaches a leaf to a stem.
The "potential of Hydrogen". The pH of soil is a
measurement of the concentration of hydrogen
ions. pH is measured on a scale from 0 to 14
pH. This indicates whether the soil is neutral,
acidic, or alkaline. For example, soil with a pH of
7.0 is said to be neutral, soil with a pH below
7.0 is acidic, and soil with a pH above 7.0 is
alkaline. Different plants require a certain pH for
optimal growth, and plant colours are
sometimes subject to change at different pH.
For instance, adding acid to the soil will make
Nikko Blue Hydrangea "bluer".
To find out what the pH of you soil is, you need
to have it tested, inexpensive test kits are
available at garden centres and nurseries.
This is the outward, physical manifestation of a
plant. Anything that is part of the observable
structure, function or behaviour of a living
organism. Every living organism is the outward
physical manifestation of internally coded,
inheritable, information.
Photoperiodism is the ratio of light and dark
periods and the response of plants to this. This
phenomenon affects flowering and plant
dormancy. Plants can be classified as ‘long day’,
‘short day’ or ‘day neutral’. The length of the
dark period is actually more important than the
Photosynthesis
Phyllode
Physiology
Phyto
Phytogenetics
Phytopathology
Picotee
Picta/Pictum
/Pictus
Pinch Back / Pinch
Out
Pine straw
Pinnata/Pinnatum
/Pinnatus
Pinnate / Pinnate
Leaf
Pip
Pisifera/Pisiferus
length of the light period. The Pointsettia is a
well known example of a greenhouse plant that
blooms in response to exposure to a dark period
over a certain length of time.
The internal process by which a plant turns
sunlight into growing energy. The formation of
carbohydrates in plants from water and carbon
dioxide, by the action of sunlight on the
chlorophyll within the leaves. The process by
which the green leaves of plants, with the aid of
sunlight, manufacture sugars and starches from
air, water, and raw food materials taken by the
roots.
A flat leaf stalk (petiole) taking on the function
and form of a leaf blade.
The science that deals with the study of
processes and functions of living organisms,
their cells, tissues, and chemical functions
including all their parts.
Prefix from the Greek word meaning plant or
plant-derived.
The study of plant (phyto-) genetics and
breeding.
The study of plant (phyto-) diseases.
A flower that has petals edged with a
contrasting, usually darker colour.
Botanical Latin term meaning painted (like
picture) - often a variegated or multicoloured
plant.
The technique of removing or 'pruning' the soft
growth at the tip of a growing shoot with the
thumb and forefinger or snipping-off with
snipers. Pinching promotes branching, (lateral
growth) a bushier, fuller plant, as well as
encouraging flowering. Also known as stopping.
Dead pine needles which are used as a mulch.
Botanical Latin term meaning having pinnate or
feather-patterned veins or leaflets. Pinnation
occurs when many small, lateral branches come
off a rib or axis.
Compound leaves with opposite pairs of
separate leaflets, arranged in rows along either
side of a midrib, as in ash trees (Fraxinus). A
series of leaflets arranged on either side of a
central stalk.
Individual underground root stock from plants
like lily of the valley and the tightly curled
leaves seen when hostas first emerge in the
spring.
Botanical Latin term meaning literally peabearing. Pisum is the genus of the garden pea.
Chamae-paris pisifera has clusters of small,
Pistal
Pistillate
Pith
Plant Pigment
Platanoides
Plume
Plunging
Pocket Garden
Pollen
Pollination
Pollinator
Post-emergence
treatment
greenish pea-shaped cones before they mature.
The female sexual reproductive seed-bearing
organ of a flower, consisting of an ovary, style,
and stigma.
A pistillate flower has one or more functional
carpels but lacks functional stamens.
Cylindrical central region of young stems, often
soft.
A standard set of plant pigment colours used for
accurate descriptions. The four main pigment
components of plant leaves are chlorophyll a,
chlorophyll b, carotene, and xanthophyll. While
most plant leaves appear green to our eyes,
several different photosynthetic pigments of
various colours are usually present in the
chloroplast of green plants. The colours of these
pigments are due to the numerous double bonds
in their structure. Chlorophyll a and b provide
the green colour of leaves, which absorb most of
the light energy needed for photosynthesis to
occur. The greatest absorption of light by
chlorophyll is in the red, blue and violet
wavelengths. Associated with these green
pigments are several other pigments known as
carotenoids. These are commonly yellow to red
in colour, and are also involved in harvesting
light energy for photosynthesis.
Botanical Latin term meaning like Platanus
(Sycamore).
Feather-like erect inflorescence - usually of a
grass or Astilbe.
The placing of a pot up to its rim outdoors in
soil, sand, peat or ashes.
A small growing area planted with miniature and
dwarf varieties.
The yellow dust produced by the anthers. The
male element which fertilized the ovule. The
male sex cells of flowering plants.
The transfer of pollen from the stamen (male
part of the flower) to the pistil (female part of
the flower), which results in the formation of a
seed. Hybrids are created when the pollen from
one kind of plant is used to pollinate and
entirely different variety, resulting in a new
plant altogether. Also, the transfer of pollen
from one flower (cross-pollination), or part of a
flower (self-pollination), to another; a critical
step in plant fertilization.
Cultivar (often a male clone) proven to pollinate
other cultivars.
Chemical treatments applied after the plant is
above ground and actively growing.
Pot Bound
Potting On
Precocity
Pricking Out
Prickle
Procumbens
Progeny Testing
Propagate
/Propagation
Prostrate
Provenance
PseudPseudobulb
PteroPubescent
Purity
Pyramidal
A plant growing in a pot which is too small to
allow proper leaf and stem growth. Roots will
start to grow in a circle in the pot.
The repotting of a plant into a proper-sized
larger pot which will allow continued root
development.
The tendency of a given species/cultivar to
mature early.
The moving of (transplanting) seedlings from a
communal growing situation, such as flats, a
tray or pot in which they were sown, to other
receptacles (individual pots) where they can be
spaced out.
A small, sharp pointed outgrowth arising from
the epidermis or bark of a plant, usually more
slender than a thorn. This is the correct term for
rose thorns.
Botanical Latin term meaning trailing low along
the ground (procumbent) as in Juniperus
procumbens.
Evaluation of seedlings of a particular cross or
source.
To multiply or start new plants by one of a
variety of techniques ranging from starting
seeds to identical clones created by cuttings,
layering, or division.
Plant which grows flat on the ground. Examples
include creeping thyme, creeping phlox and blue
rug juniper.
Refers to the geographic and climatic origin
from which plants or propagation material are
obtained. For seeding material, the provenance
is the harvest location; for plants, it is both the
harvest location and the location of the nursery.
A proper way to denote a provenance in plants
collected in the wild would be "Boulder Mt. 2200
ft." or "Cypress Swamp north edge".
Prefix meaning false, usually as part of a
botanical name.
The swollen stems of orchids, which appear
bulb-like, storing food and water.
Botanical Latin prefix meaning winged.
Covered with short, soft hairs.
The relative genetic stability and uniformity of a
breeding line.
Pyramid-shaped with a wide base and narrow
top. May refer to plant or flower shape.