Welcome to our Pollinator Field Note Series! Offshoots released a Pollinator Action Plan with the City of Somerville, in collaboration with bee scientist and expert Nick Dorian. Continue reading to take a sneak peek into our conversation about native plants, cultivars, and nativars!
___________________________________________________________________________________
Natural Landscapes Support Urban Pollinators
Pollinators are essential to ecosystems and food production, yet their populations are declining due to habitat loss, pesticide use, invasive species, light pollution, and climate change. Urban development and agricultural expansion have fragmented once-diverse landscapes, replacing them with lawns and non-native plants that offer little value to pollinators.
These animals rely on connected habitats for nectar, pollen, nesting materials, and host plants, often traveling hundreds of yards or more to find resources. Ensuring connectivity between habitat patches is critical for their survival.
Pollinator gardens in urban areas can help restore these connections while also engaging communities. When people appreciate and interact with pollinator-friendly spaces, they are more likely to support conservation efforts, creating a cycle that benefits both pollinators and people.
___________________________________________________________________________________
To understand pollinators, you must know about native plants, cultivars, and nativars
A native plant is one that was found naturally in our area pre-European settlement (Rodomsky- Bish, 2018). Although some non-native species may provide food for pollinators, native plants generally attract more pollinators than non-native species (Seitz, van Engelsdorp, & Leonhardt, 2020; Salisbury et al., 2015), and provide essential nesting and overwintering habitat. Native plants are vital to supporting native insects, in particular the specialist pollinators, at the bottom of the food web. These native plant and insect interactions are key to a functioning ecosystem.
A cultivar, as defined by Becca Rodomsky-Bish (2018) of the Cornell Lab of Ornithology, is: A cultivated version of a plant bred by horticulturalists through cloning or hybridization, seeking to enhance an aesthetic quality or encourage disease resistance that can be maintained through propagation. This means these populations of plants may have different characteristics than what you would commonly find in the wild, even if they are still the same species.
You can identify that a plant is a cultivar when the scientific plant name is followed by a descriptive name in quotes (i.e. Genus species “Cultivar”).
Nativars, a term used to describe the cultivars of native plants, may be a cross of two or more plants intentionally selected for desirable traits, or they may be a straight species of a plant collected from the wild and given a cultivar name (Rodomsky-Bish, 2018). For example, Aster ‘Purple Dome’ and Solidago ‘Fireworks’ are two native plants collected in the wild with desirable characteristics but sold under cultivar names (Caton, 2023).
Below, in Images 1 and 2, is an example of the New England Aster and one of its cultivars:
_______________________________________________________________________________
Image 1: Example of plants native to the Northeast: Symphyotrichum novae-angliae or New England Aster
Image 2: New England Aster’s nativar: Symphyotrichum novae-angliae ‘Purple Dome’ Image sourced from Missouri Botanical Garden
Cultivars are produced by nurseries through various reproduction methods including growing by seed or clonal cuttings. Clonal cuttings are exact replicas of the parent plant and have lower genetic diversity. Seeded plants have the benefit of higher genetic diversity, which may be helpful for plants adapting to local conditions if they reproduce spontaneously in the future (Caton, 2023). Some cultivars support pollinators as well as their straight species counterparts, and some do not. In the nursery trade, nativars are often more available than the wild species since there is demand for plants with specific traits such as a shorter height, flower color, longer bloom time, or double bloom.
According to research conducted on pollinator visitation to native cultivars, Baker et al. concluded that native milkweed cultivars are just as effective as their wild counterparts in attracting and supporting monarch butterflies and native bees in small gardens. While wild, native plants are essential for maintaining genetic diversity in natural habitats, using cultivars in urban gardens is an excellent way for the public to contribute to pollinator conservation.
Given this information, it is important to choose nativars that look the most like their straight species counterpart, prioritizing bloom color and flower shape.
___________________________________________________________________________________
This research was a part of Offshoots’ research project in partnership with the City of Somerville and field scientist Nick Dorian, to create the Somerville Pollinator Action Plan (SPAP). Citations and links to academic articles can be found in the SPAP document. To learn more about the action plan, visit our SPAP projects page here.
Caton, I. (2023, November 31). Species diversity [Conference presentation]. Ecological Landscape Alliance, Ecological Plant Conference, Brooklyn, NY.
Rodomsky-Bish, Becca (2018) Nativars (Native Cultivars): What We Know & Recommend. Habitat Network by Cornell Lab of Ornithology http://content.yardmap.org/learn/nativars-nativecultivars/
Seitz, N., vanEngelsdorp, D., & Leonhardt, S. D. (2020). Are native and non-native pollinator-friendly plants equally valuable for native wild bee communities? Ecology and Evolution, 10(22), 12756 12765. https://doi.org/10.1002/ece3.6826