Halophyte
Plants modified to cope with salt or alkaline conditions
Hardening Off
The process of gradually exposing seedlings started indoors to outdoor conditions before transplanting.
Hardiness
The ability of a plant to withstand winter cold, especially frosts; often expressed in terms of geographic zones which work for both hemispheres - just inverted.
Heeling in
The temporary burying of the roots of newly dug plants to prevent their drying until the new planting site is prepared.
Herb
the term generally refers to a plant grown for its medicinal or flavoring properties or for its scented foliage. A shortening of herbaceous.
Herbaceous
Dies back to the ground in winter. Generally applied only to non-woody biennial and perennial plants.
Herbicide
A chemical that is used for killing unwanted plants or to prevent seeds in the ground from sprouting. It works by penetrating the foliage and systemically killing the plant.
Heterophyllus
A greek word used in plant naming meaning - different leaf shape
Hip
The closed and ripened receptacle of a rose that contains the seeds. They are often brightly colored and are removed by keen gardeners to save the plant energy that can be used instead for repeat flowering. (deadheading)
Hooks
Are backward facing thorns they grow from the leaf axil and help the plant climb. These can be seen on Bougainvillea
Horticulture
The term includes the art, science, technology, and business of the cultivation of plants for ornament or food. It also includes landscape design, construction, maintenance, restoration along with the conservation of plants and arboriculture.
Humus
Partly or wholly decomposed vegetable matter that contains many living bugs and enzymes. it is an important constituent of healthy garden soil and assists drainage while retaining enough moisture for plants to access.
Hybrid
A plant resulting from a cross between two distinct parents.
Hybridisation
The transfer of pollen from the anther of one plant species to the stigma of another species. In most cases the the species are of the same genus. The hybrids tend to be sterile and grow faster and bigger than their parents.
Hydrophyte
A plant modified to grow in or on the surface of water
Hydroponics
A method of growing plants without soil but in water instead. Plant foods are fed into the circulating waters.