Half hardy
A plant which cannot survive cold weather conditions without protection.

Half-standard
A tree with 90cm (3ft) or more of clear stem.

Hardening off
The process of gradually acclimatizing plants, raised in warm conditions, to cold conditions.

Hardy
A plant which can survive cold weather conditions without protection.

Heeling in
The temporary planting of new stock whilst waiting for correct weather conditions.

Herbaceous
A plant which does not produce a permanent woody stem.

Herbicide
Weed killer.

Hermaphrodite
See bisexual.

Hirsute
Covered with stiff or coarse hairs.

Honeydew
Sticky secretion deposited on leaves by whitefly and aphids.

Hose-in-hose
Flowers which look like they have one bloom inside another.

Humus
Jelly like organic matter in an advanced state of decay.

Hybrid
A plant derived from a cross between two (sometimes more) species.

I

Imbricate
Closely overlapping.

Inflorescence
The flowerhead, the part of the plant bearing the flowers.

Inorganic
A chemical or fertilizer which is not derived from natural sources.

Insecticide
A chemical used to control insects and small pests.

Internode
The part of the stem between nodes.

Involucre
A ring of bracts surrounding a flower.

J

John Innes composts
Loam based composts used for raising young plants.

Joint
See node

K

Keel
Boat-shaped structure made by the two lower petals of members of the Leguminosae.

L

Lanceolate
Spear shaped.

Lanky
Spindly growth giving a sparse, gaunt appearance.

Larvae
The immature stage of some insects, for example, caterpillars.

Lateral shoot
A shoot arising from a main stem.

Layering
A form of propagation where new plants are formed from the parent plant whilst still attached to it.

Leaching
The downward movement of water resulting in the loss of soluble chemicals.

Leader shoot
The main shoot which extends the growth of the branch.

Leaflet
One of the parts of a compound leaf.

Leaf mould
Peat-like substance made of partly decomposed leaves.

Leguminosae
The Pea Family.

Light
The movable glass part of a cold frame.

Linear
Very narrow with parallel lines.

Line-out
To plant out young plants in a temporary site.

Lime
A compound containing calcium and/or magnesium and is used to reduce the acidity of the soil.

Loam
A good friable soil which is neither full of clay nor sand.

Lobe
A rounded segment protruding from the rest of the leaf or petal.

Long Tom
A deep pot, about half the depth again of a normal pot.