In botany, the term "perennial" is generally used for the category of plants that live for more than one year, in contrast to annuals which complete their life cycle and die withing a year or biennials that mature, set seed and die in a two-year cycle.
In horticulture, "perennial" is usually applied to flowers other than annuals/biennials that are not woody or only only somewhat woody (versus true trees and shrubs which are technically perennial too). Examples are salvias, chrysanthemums and gerberas. It's a loose term whch might also include bulbous plants and ornamental grasses, considering the decorative ways in which they are used in the garden. Perennials are often associated with cottage gardens and traditional flowery English-style gardens.
Many perennials you'll see in gardening books are unsuitable for most of Queensland. Unless you live in more temperate areas like Toowoomba and Granite belt, success here starts with selection of types suitable for tropical conditions. Be sure to check suitability for your climate when ordering perennials from mailorder suppliers based in the southern states.
More Online Information
The following links are for general information, research and ideas - some species or cultivars referred to in overseas publications may be unavailable in Australia or unsuitable for Queensland conditions
Cornell University Cooperative Extension
Washington State University Clark County Extension
Advice for professional growers from Western Australia Department of Agriculture (PDF)
| ||Secrets of the black dahlia|
A study of the "black" dahlia has revealed that the large amounts of red anthocyanins are produced due to a lack of flavones (associated with white flowers) competing for biochemical building blocks. It is not caused by increased activity of the anthocyanin pathway. The findings are a step towards engineering flavone content of plants. Source: Le Rouge et le Noir: Where the black dahlia gets its color (November 2012)
Dianthus and Carnation
Hybridisation of D. barbatus with D. chinensis). University of Arkansas
Eranthemum, Brisbane, early September 2013
Eranthemum plant habit. Red foliaged shrub on the right is a croton. (Macgregor, Brisbane, September 2013)
) Washington State University
Kentucky Garden Flowers, University of Kentucky
Notes on history and naming. Parker County Master Gardener Association, Texas (PDF)
More to come in future updates