Most people know that plants have been given botanical names. Why can't we use common names, as they are much easier to learn than those difficult Latin names? For several years I managed to purchase plants getting along with common names. Then it happened. I walked into a nursery and told the owner I was looking for a specific plant called Beacons, or Silver Beacons. The man frowned; looked confused and said he didn't know the plant. I described the perennial and he said (under his breath) "these stupid common names always cause problems, why don't people ask for the proper name of the plant?" I was somewhat embarrassed and vowed I would never attend another nursery without researching the proper name. Others may never shop at his store again, but his selection is phenomenal and truth of the matter is I was wrong to guess at the name of a plant and hope that by some miracle he would know what I was talking about.
The Beacon or Silver Beacon I was trying to purchase could not be located so I did research the plant and established the proper name. It is Lamium maculatum. That is indeed a far cry from Beacon however the common name can be 'Beacon Silver', 'Deadnettle', 'Chequers', 'Pink Pewter' and quite often certain common names are only known locally. In retrospect it is understandable that nurseries cannot recognize a plant simply by description accompanied with an unusual common name.
Botanical names are recognized worldwide, so there is no mistaking which plant is being talked about or ordered from nurserymen. Some plants do not have common names and several different plants share the same common name.
According to my research the Ancient Greek philosopher Theophrastus began it all with a list of about 450 plants. This occurred approximately 2000 years ago. In 1753 a Swedish botanist named Carl Linnaeus published 'Species Plantarum'. Plant naming was put on to a scientific and orderly footing.
Carl Linnaeus founded the binomial (two-name) system outlined below and each genus has a different name.
Hedera: is the name of genus. This is equivalent to a surname and is capitalized.
helix: is the name of the species. This is equivalent to a Christian name and is typed in lowercase. The combination of Hedera and helix denotes the specific plant.
In summation the genus equals the surname for example 'Smith' and the species identifies the Christian name example 'Oscar', and when combined we have the proper name being 'Smith oscar'.
Only one type of plant can have this name. Once the full Latin name has been used a nearby reference is abbreviated. For example H. helix may have several closely related varieties. The variety name is usually in Latin. An example of this could be H. helix cristata or H. helix scutifolia. In terms of proper names for people it would be something like this 'S. oscar feline'.
If the variety originated in cultivation and not in the wild then it is called a cultivar (which is an abbreviation for "cultivated variety"). The cultivar name is usually not in Latin. For example H. helix Chicago could be the proper name of a specific plant. Comparing my example above using the name Oscar and Smith the proper name would be 'S. oscar feline Toronto'.
Common Ivy: is the popular name for Hedera Helix. However a number of different plants can have the same common name. For example Zebrina pendula and Tradescantia fluminensis are popularly known as "Wandering Jew". Some single species have more than one common name for example Impatiens wallerana is known as "Busy Lizzie" in Britain and "Patient Lucy" in the U.S. For these reasons it is usually better to refer to plants by their Latin names.