True to type

Understanding how plant breeding is reflected in plant names

Remember Mendel’s peas? The wrinkled and the smooth? In the1850s Mendel planted peas in a monastery garden. He cross-fertilized them and painstakingly recorded the results, unlocking the secrets of heredity and opening the door to modern genetics.

Mendel’s work is still relevant to hobby gardeners today. And even if you don’t fancy creating your own variety of plant, understanding what’s in name can be helpful to the home gardener.

We’re going to get technical here, so if you’re looking for a quick takeaway: the closer to the original species, the truer a plant will be to type.

Let’s imagine a sample tag from a garden centre that reads: Dianthus barbatus ‘Sooty.’ The first name is the genus, the second the species, and the third epithet, the cultivar.

By contrast, the common name for Dianthus uses no Latin binomial (the two-part genus/species name) and would simply be: Sweet William. But you’d still need to know what kind of Sweet William you have before you because the plant comes in a wide range of varieties (and species) and subsequently colours. Hence the need for the species and cultivar name, the latter presented in single quotes; ‘Sooty.’ What you can read into this is that from D. barbatus a form was selected for certain attributes – in this case deep plummy blooms and dark foliage.

Got it? So far we’ve covered three types of names: common, binomial and cultivar.

Cultivar names also appear without a species name, for example Geum ‘Scarlet Tempest.’ In this case, it’s wise just to think about the meaning of the word cultivar which comes from the two words ‘cultivated’ and ‘variety.’ A cultivar does not appear in the wild. For example, this Geum was bred by Elizabeth MacGregor in 2012 from parentage of G. ‘Beech House Apricot’ x G. chiloense ‘Red Dragon’), telling us that wild ancestors are distant indeed.

Confused yet? We can go further! What does it mean when you see a number listed next to a plant name?

Frankly, this question led me to write this column. I have a small specialty cut flower business so I tend to look for new varieties. This morning I was flipping through a trade publication and came across this: Eustoma grandiflora F1, Rosanne 1.

Eustoma is also known as Lisianthus and is a great plant, but tough to grow in our cool summers, hailing as it does from the central U.S. The wild form is pretty, but the cultivated varieties are taller, more floriferous and hold long in the vase, so a tremendous amount of breeding has gone into the creation of new colours and flower types.

An F1 hybrid is the result of crossing two pure lines to achieve a desired result (in this case, a pinky brown). It may have taken a breeder seven or more years to breed a pure line before crossing but once done, those plants will produce seeds embodying the desired traits. These seeds are the F1 generation and if they themselves were planted and matured to seed their offspring wouldn’t necessarily have the same traits. As Mendel found: Only the first generation crossed from pure lines will. Hence, these seeds are often more expensive. As for the 1 listed with the ‘Rosanne’ – as far as I can tell (given no one called me back from the seed company in California) it refers to the group of Lisianthus which have standard double flowers.

Kind of makes you appreciate the wildflowers, huh?

Christin Geall is an avid Oak Bay gardener and creative non-fiction writing instructor at the University of Victoria. Email