F1 HYBRIDS: The first generation from a cross between two plants. This expression has come to refer to plants raised in this way by plant breeders from specially selected parents. seed so obtained is usually expensive because of the amount of effort which has gone into its production, but the resultant plants are very strong and healthy (this is known as hybrid vigour), with special characteristics purposely bred into them. Seed from F1 hybrids will not breed true to the parent plants; the resulting seedlings are known as F2 hybrids and usually turn out to be a pretty motley crew, though not, in many cases, without their own merits.
FAMILY: A group of several genera (see genus) of plants. For example the rose family (Rosaceae) contains many smaller groups (genera) such as malus (apples), pyracantha (firethorn) and cotoneaster, all with basically similar characteristics.
FAMILY TREE: One where more than one variety has been grafted on to one rootstock. This is often done with apples and pears, to enable several sorts to be grown on one tree when space is limited.
FAN: A method of shaping certain plants, often plums, peaches and figs, in which branches are trained into a flat fan-shape and supported by a fence, wall or similar means.
FARMYARD MANURE: Animal excreta and straw or other bedding materials, partially rotted down, which is a rich source of humus and plant foods when incorporated into soil.
FASTIGIATE: A tree with an erect growth habit, such as the Lombardy poplar.
FEATHERED: You will sometimes encounter this expression in nursery catalogues. It means a young tree with branches growing right down the stem, instead of having a clear trunk.
FERN: A rather primitive group of green plants which do not flower, and reproduce themselves by spores instead of seeds.
FERTILE: A plant is fertile if it is capable of producing seed, soil is fertile if it is of good texture, rich in humus, beneficial organisms and plant nutrients, and thus able to support strong, healthy plants.
FERTILIZATION: The fusion of a male and female cell. In the case of plants, this happy event ultimately produces a seed.
FERTILIZER: A compound providing plant foods, usually in a concentrated form.
FILAMENT: The part of the male organ of a flower supporting the anther.
FLESHY-ROOTED: Plants with thick, fleshy roots.
FLOWER: The sex organs of a plant, usually surrounded by a protective ring of often eye-catching petals and sepals which attract creatures for pollination, so that a seed or seeds can be formed.
FOLIAGE: The leaves of a plant.
FRAME (COLD FRAME): A protective structure, made of glass or other transparent material, similar to, but generally lower and smaller than, a greenhouse. It can be used in a similar way to a cloche, and also for hardening off young plants raised in heat to prepare them for planting out. Frames are usually placed horizontally, although narrow, vertical frames are also available for attaching to a wall.
FROST: This arises when the temperature falls below 32°F (0°C) and can be damaging to tender plants not suited to low temperatures, unless protection is given in some way.
FRUIT: Any seed-bearing organ: a pod, a berry and a nut are all technically ‘fruit’.
FUNGICIDE: A chemical formulated specifically for controlling fungus diseases on plants.
FUNGUS: A type of plant which contains no chlorophyll and therefore, unlike green plants, cannot make its own food. A fungus derives sustenance from other living things, when it is known as a parasite, or dead ones, when it is a saprophyte. Saprophytic fungi can be very beneficial in that they help to break down dead matter into food for other plants as well as themselves, but some parasitic ones cause disease on plants, and have to be controlled with fungicides.