Native Plant Species & Cultivars

By Elaine Mills, Extension Master Gardener & Coordinator at the Glencarlyn Library Community Garden
Photos by Elaine Mills

Part of the learning curve of growing native plants is understanding that some are available as “straight species” and others as cultivars. But what does that mean, and does it matter? An advantage of choosing the straight species – the form found naturally in the wild – is that these plants have evolved with the local wildlife, and they will be recognized as excellent sources of food. Cultivars, however, have been produced through breeding for ornamental traits, principally with human preferences in mind.

Identification of Straight Species and Cultivars

Species are designated by an italicized two-part Latin name, while cultivars are indicated by an additional name in single quotes. For example, Heuchera villosa is the scientific name for hairy alumroot, and Heuchera villosa ‘Autumn Bride’ is the name of a cultivar you’ll find in the shade garden area of the Glencarlyn Library Community Garden. The ‘Autumn Bride’ cultivar  has been bred for its showy flowers. Using Latin names is a way to make certain you get the plant you want, because multiple plants may be known by the same common name or the same plant may be known by multiple common names. For example, Heucheras are commonly called both alumroot and coral bells.

Understanding the Impact of Choosing Straight Species or Cultivars

The underlying purpose of your plant selection will likely guide your choice as to whether to select a straight species or cultivar. Key to finding the best option is understanding how certain ornamental alterations to a straight species might impact the cultivars’ value to wildlife.

One reason gardeners may choose a cultivar of a native species (sometimes referred to as a “nativar”) is to find a compact plant for a small space. For instance, while we have the straight species shrub Virginia sweetspire (Itea virginica) in the native plant section of our garden, we have planted the shorter ‘Henry’s Garnet’ cultivar in our patio area and the diminutive ‘Scentlandia’ in the narrow parking lot bed. These cultivars have been modified for height, but their other characteristics remain the same, meaning that they will still be supportive of wildlife.

[USE ‘Henry’s Garnet’ from Glencarlyn version, plus photos for species and ‘Scentlandia’]

Other types of changes introduced into cultivars can be problematic. First, when the color of a shrub’s foliage is changed from the natural green to orange or red, the chemistry has been altered, and the plant will not be palatable for the critical caterpillar stage in the lifecycle of our butterflies and moths. To illustrate, the ‘Amber Jubilee’ cultivar of common ninebark (Physocarpus opulifolius) we have planted in the adjacent cemetery is beautiful but cannot serve as a larval host plant.

Modifications to flowers, especially changes in structure, will have a negative effect on pollinators. We grow the straight species purple coneflower (Echinacea purpurea) in our herb beds, but there are numerous commercial cultivars in which additional petals have been substituted for the reproductive parts in the prominent central cone. These fluffy, double-flowered types are sterile and offer no pollen or nectar to bees or butterflies.

For gardeners seeking a wider choice of straight species with carefully selected cultivars, we recommend referring to lists of native-only sellers and periodic plant sales compiled by the Plant NoVA Natives campaign.

To learn more on this topic, register for the upcoming public education presentation on “Native Plant Species & Cultivars” scheduled for Friday, May 10, 2024 from 10:00 to 11:30 a.m. via Zoom. Extension Master Gardener Elaine Mills has conducted research on past and on-going studies comparing native plants and their cultivars from the standpoint of garden performance, visits by pollinators, and use as larval host plants, and she will summarize her findings in this presentation. Included will be information on a study of woody plants by Dr. Douglas Tallamy and Emily Baisden; the Bees, the Bugs & Blooms pollinator trial by Penn State Extension; field trials of herbaceous plants by Dr. Annie White; multi-year trials of native plants and cultivars conducted at Mt. Cuba; and the Garden Ecology Lab study at Oregon State University.