Using Cultivars when Gardening with Native Plants
Cultivars, or “cultivated varieties” of plants, are common in the nursery trade and popular with gardeners. Cultivars are selected for their desired traits, and are most often asexually propagated to retain those characteristics. Desired traits can include a flower color, a compact growth habit, improved disease resistance, and more. However, there has been a pushback in recent years from the native plant enthusiasts to the overuse of cultivars in our gardens.
As mentioned before, cultivars are most often asexually propagated, meaning they lack genetic diversity. Genetic diversity in a population of plants is beneficial for the population and the greater ecosystem. For example, a diversity of bloom times can help plant populations overcome extreme weather events and provide a long forage season for pollinating insects.
Often, cultivars are less useful to their broader ecosystem than the “wild-type” species. Double flowers offer less nectar and pollen for pollinators, and red foliage selections are less palatable to herbivores.
However, I think there are instances where cultivars of native plants can be used appropriately. If a cultivar offers improved performance in cultivation, improved disease resistance, cold-hardiness, or a habit that makes it suitable for urban gardens, then this makes using a native plant more accessible to gardeners, and increases the diversity of native plants that gardeners are able to use effectively.
Wild-types can also be frustrating to gardeners. Sexual reproduction can introduce deleterious traits that would quickly be weeded out in nature. This can be difficult to accept when a native plant has been sold to someone with the promise of it being lower maintenance, more disease resistant, and better suited for our climate than non-native ornamental plants. On the other hand, genetic recombination can introduce new, desirable traits to the gardener who is willing to cede some control to mother nature.
Ultimately, it comes down to why you are using native plants. For restoration projects, seedling plants with a greater genetic diversity should be used, and losses should be expected. In gardens, wild-type species and cultivars can be appropriately selected to improve success and more effectively create habitat and support ecosystems.
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