Native species vs nativars: the real debate
"Nativars" -- cultivated varieties (cultivars) of native plant species -- have become a central controversy in ecologically minded gardening circles. The debate is straightforward in principle: when you buy 'Black Lace' elderberry (*Sambucus nigra* 'Black Lace') instead of the straight-species.
—- title: "Native species vs nativars: the real debate" slug: native-plants-vs-cultivars-debate hub: plants category: "Advanced technique" description: "An evidence-based examination of the nativar debate: whether cultivars of native plants support wildlife as well as straight species, with the current research findings." date: 2026-06-10 updated: 2026-06-10 author: "Thomas A." reading_time: 9 —-
"Nativars" — cultivated varieties (cultivars) of native plant species — have become a central controversy in ecologically minded gardening circles. The debate is straightforward in principle: when you buy 'Black Lace' elderberry (Sambucus nigra 'Black Lace') instead of the straight-species native Sambucus canadensis, does it provide the same ecological value to native wildlife? The answer, increasingly, is: it depends on which trait was changed.
Per Xerces Society research, changes in flower color, flower structure, and foliage color — all common in cultivar selection — can significantly affect the ability of native insects to use those plants.
What the research actually says
Riedel et al., 2016 (Native Plants Journal)
Per research cited by Xerces Society, Riedel et al. (2016) compared insect visitation to straight-species coneflower (Echinacea purpurea) and several nativars with altered flower color and structure. Native bees visited straight-species plants at higher rates than double-flowered nativars. Single-flowered cultivars with similar flower architecture showed comparable or only slightly reduced visitation.
Key finding: Double-flowered forms (where petals replace reproductive structures) and forms with dramatically altered flower color reduce pollinator access significantly.
PennState Extension nativar research
Per Penn State Extension, entomologists at Penn State compared straight Echinacea purpurea, several nativar selections, and non-native controls for bee diversity and visitation rates. Results showed:
- Straight-species plants attracted significantly more native bee species than most nativars
- Some nativars with minimally altered flower color attracted similar bee diversities to the straight species
- Double-flowered and non-typical-color nativars attracted substantially fewer native bees
Tallamy's caterpillar data
Dr. Douglas Tallamy (University of Delaware) has studied the host plant use of Lepidoptera (caterpillar-producing moths and butterflies) on native plants and nativars. Per Xerces Society summarizing his work, dark-foliaged nativars of native plants (like dark-leaf elderberry, dark-leaf coneflower) may reduce caterpillar feeding. Caterpillars rely on plant chemistry (secondary metabolites), and cultivar selection often changes those metabolites alongside the visible traits.
This is a hypothesis with supporting data, not a closed conclusion. The degree of change varies by species and cultivar.
Which cultivar traits reduce ecological value
Per Xerces Society analysis:
| Trait change | Ecological impact |
|---|---|
| Double flowers (petals replace stamens/pistils) | Pollen and nectar inaccessible or absent; significant reduction in pollinator value |
| Dramatically altered flower color | May reduce recognition by native specialist pollinators; evidence is species-dependent |
| Dark/black foliage | Possibly reduces caterpillar palatability; reduced evidence quality |
| Sterile cultivars (no fruit/seed) | Eliminates fruit-based wildlife value; significant for fruiting native shrubs |
| Compact habit | Little apparent ecological impact if flower and foliage chemistry unchanged |
| Slightly altered flower color (within natural variation) | Minimal or no measured impact |
| Larger/smaller flowers (same structure) | Minimal impact if structure is preserved |
The straight-species advantage
Per Missouri Botanical Garden and Lady Bird Johnson Wildflower Center:
Straight species native plants are adapted, over evolutionary time, to the specific pollinators, caterpillars, birds, and other organisms of their native range. The chemical and morphological signals in the flowers, foliage, and seeds match what native wildlife is looking for.
Cultivars were selected by humans for characteristics that appeal to gardeners — not to wildlife. That selection pressure can inadvertently alter traits wildlife depends on.
The nativar defense
Proponents of nativars (including some Extension horticulturists) argue:
- Gardeners won't plant boring plants. If a double-flowered coneflower or dark-leaf ninebark is the difference between a gardener planting natives or not planting natives at all, the net ecological outcome may favor the nativar.
- Proximity effects matter. Native plants benefit from being in the landscape even if individual cultivars have reduced wildlife value — they contribute to local plant diversity, reduce the need for chemical inputs, and provide some resources even if not optimized.
- The research is incomplete. Most nativar studies cover a small number of species; extrapolating to all nativars is premature.
Per NC State Extension, all three points have merit and are used by Extension educators in nuanced recommendations.
Practical guidelines
Per Xerces Society and Penn State Extension:
- For pollinators: Avoid double-flowered forms of any native species; single-flowered cultivars with natural flower architecture are generally acceptable
- For caterpillars: Prefer straight species when planting woody natives specifically for caterpillar habitat; dark-foliaged cultivars may reduce value
- For fruit-eating birds: Avoid sterile nativars (some Sambucus, some Ilex selections are selected for ornament without fruit); choose fruiting cultivars or straight species
- For overall landscape plantings: A mix of straight species and minimally altered nativars is more defensible than all nativars
The "50% rule" (Tallamy suggestion)
Dr. Douglas Tallamy has suggested, per Xerces Society reporting, that dedicating at least 50% of landscape space to straight-species native plants while allowing nativars in the remainder is a practical guideline. This is not a peer-reviewed conclusion but a practical heuristic.
Frequently asked questions
Is 'Walker's Low' catmint (a cultivar) good for pollinators? Nepeta × faassenii 'Walker's Low' is a nativar not of a North American native species but of a Central Asian species. Per Xerces Society pollinator plant lists, it is documented as a valuable pollinator plant in North American gardens — a case where a non-native cultivar has measurable pollinator value. The nativar debate applies most specifically to cultivars of species native to your region.
Does 'Knock Out' rose have wildlife value? Per Penn State Extension, 'Knock Out' roses attract some bees (pollen collection) but are not native and do not support native caterpillars. They do not substitute for native rose species (Rosa carolina, R. palustris) for Lepidoptera specialist insects.
Are all double-flowered plants equally problematic? The double-flower concern is primarily about pollinator access to nectar and pollen. Per Xerces Society, plants where the doubled petals completely replace reproductive structures (hose-in-hose forms, fully "blown" roses) have no pollen or nectar available. Plants where the doubling is partial may still provide some pollen.
What is the bottom line for a Long Island garden? Per the research synthesis: if you have limited space, prioritize straight-species natives for woody plants (viburnum, serviceberry, bayberry, native roses) and tolerate minor nativars for perennials where the flower architecture is preserved. Avoid double-flowered and sterile forms for anything with primary wildlife intent.
Recommended gear: Best [coneflower cultivars beyond purple](https://outdoorplantcare.com/plants/best-coneflower-cultivars/) — our buyer's guide covering picks for every budget, ranked by Extension publication consensus and personal use.
Sources
- Xerces Society — Nativars and conservation horticulture
- Xerces Society — Pollinator plant lists
- Penn State Extension — Nativars and pollinators
- NC State Extension — Native plant selection
- Missouri Botanical Garden — Native plants overview
- Lady Bird Johnson Wildflower Center — Native plant database