By Val Whitmyre, U. C. Master Gardener
William Shakespeare aside, a rose by any other name is not a
rose, even if, like a rose-scented geranium, it smells like one. Gardeners
need to know the correct names of plants to distinguish them from each other.
They need to know a plant's growth habits and environmental requirements
to know what to expect of them. Is it a poisonous plant or an edible one?
Is it evergreen or deciduous? Botanical plant names often provide the answer.
Plants are like people. Most of us have three names to distinguish
us from others. Most of us have relatives that share a few similarities, such
as blue eyes or curly hair.
Gardeners identify plants using an orderly classification system.
The broadest category is the plant's family, followed by its genus, species,
and variety. Each of these categories narrows the similarities until a plant
is specifically identified. Latin, or botanical, names are used universally.
In that way, we may be precise in naming and recognizing plants wherever we
are. In contrast, common names for the same plant may differ. What a Californian
calls lupine (Lupinus genus) is a bluebonnet in Texas, and our jasmine (Jasminum
genus) is pikake in Hawaii. Common names are, for the most part, used locally
rather than internationally.
Some plants, such as rhododendron, eucalyptus and protea, have
no common names. Over time and through usage, the botanical names for these
plants have become their common names.
I happen to love the sounds of words, while some people fight
with a word until they give up. But if you take the word apart, it's
easy to see what it's trying to tell you.
Rosaceae is a family name. Rosa sounds like rose, and family
names end in -aceae. Pine trees are members of the Pinaceae family. Lilies
are members of the Liliaceae family.
Potatoes, tomatoes, peppers, eggplants, petunia hybrids, cup-of-gold
vine, schizanthus ("poor man's orchid"), nicotiana (a poisonous
tobacco plant) and night jessamine are a few of the hundreds of plants in
the Solanaceae family. They may seem to be unrelated, but the leaves tend
to be hairy and the flowers are star- to bell-shaped with five lobes. They
run the gamut from vines to shrubs to annuals to vegetables, yet all are part
of this family.
Within each plant family are one or more genera (the plural
of genus), a category that contains related species. The species is the basic
unit of plant identification. If you look in the Sunset Western Garden Book,
you will see Rosa, which is spelled out at first and then shortened to R.,
followed by the species name—for example, R. damascena, the damask rose.
The species name may be followed by a variety or cultivar name, such as R.
damascena 'Rose of Castile.'
A variety differs from other members of its species in some
significant way, such as leaf color. A cultivar is similar to a variety but
is typically a hybrid, not a natural cross. Variety and cultivar names are
often descriptive, such as R. 'Altissimo' (a very tall climbing
rose) or fanciful, such as R. 'Double Delight.' Because a species
may include hundreds of varieties (in the case of apples) or even thousands
(in the case of rhododendrons), it is important to know the variety name.
You want the right plant for each spot in your yard.
References:
Illustrated Introduction to Shakespeare's Flowers
New Pronouncing Dictionary of Plant Names
Sunset Western Garden Book
Ornamental Plants, Their care, use and identification, D. Dwight Wait
Shorter Dictionary of Gardening
Sustainable Gardening, Master Gardening Handbook.