Keystone Plants Guide: The Native Plants That Feed 90% of Specialist Insects and How to Choose by Region
Not all native plants are equal for wildlife. Keystone plants — oaks, wild cherries, willows, goldenrods, and asters — support hundreds of times more caterpillar and bird species than ornamental alternatives. Here’s how to choose them for your US garden.
Most gardeners understand that native plants support more wildlife than non-native ornamentals. What fewer realize is how extreme the disparity actually is — and how concentrated that ecological support is in a relatively small number of plant families. University of Delaware entomologist Dr. Doug Tallamy spent years mapping which plants support which caterpillar species across North America, and his findings reshaped how scientists think about home landscapes. The result: a concept now central to wildlife gardening — the keystone plant.
A keystone plant is not simply any native species. It is a plant genus that supports a disproportionately large number of wildlife species relative to its abundance in the landscape. Tallamy’s research found that the top 14% of native plant genera support 90% of caterpillar species in any given region. At the extreme end, a single mature white oak (Quercus alba) in the eastern US hosts more than 534 caterpillar species. These caterpillars, in turn, are the primary food source for virtually every songbird during nesting season — a pair of black-capped chickadees alone needs between 6,000 and 9,000 caterpillars to raise one clutch of chicks. Remove the oaks, and the birds go with them.
This guide identifies the most productive keystone plants available to US gardeners, explains why they outperform non-native alternatives by such wide margins, and shows you how to incorporate them into a beautiful, functional wildlife garden across any USDA hardiness zone.
Quick Reference: Top Keystone Plants by Wildlife Support
| Plant Genus | Caterpillar Species* | USDA Zones | Best For |
|---|---|---|---|
| Oaks (Quercus spp.) | 534 | 3–9 | Birds, moths, butterflies, acorn wildlife |
| Wild Cherries (Prunus spp.) | 456 | 3–9 | Birds, native bees, tiger swallowtail |
| Willows (Salix spp.) | 455 | 2–9 | Birds, moths, early spring pollinators |
| Birches (Betula spp.) | 413 | 2–7 | Birds, moths, seed-eating finches |
| Poplars/Cottonwoods (Populus spp.) | 368 | 2–8 | Birds, moths, tiger swallowtail |
| Maples (Acer spp.) | 285 | 3–9 | Birds, moths, early-season bees |
| Native Blueberries (Vaccinium spp.) | 288 | 3–9 | Birds, native bees, edible fruit |
| Native Roses (Rosa spp.) | 139 | 3–9 | Birds, native bees, bumblebees |
| Goldenrods (Solidago spp.) | 115 | 3–9 | Butterflies, bees, seed-eating birds |
| Native Asters (Symphyotrichum spp.) | 112 | 3–8 | Monarchs, bees, migrating butterflies |
*Eastern US caterpillar species data from Tallamy & Shropshire (2009). Western US counts vary by region but the same genera dominate.
What Are Keystone Plants?
The term “keystone species” originates in ecology, describing a species with an outsized effect on its ecosystem relative to its biomass or abundance. Remove the keystone species, and the ecosystem collapses or transforms dramatically. Dr. Tallamy adapted this concept for plants, coining “keystone plants” to describe the plant genera most critical to sustaining wildlife food webs in North American gardens and landscapes.
The mechanism works through caterpillar biomass — the sheer weight and density of insects a plant can produce. When ecologists calculate which plants contribute most to local food webs, they measure how many Lepidoptera (moths and butterfly) species use a plant as a larval host. Caterpillars matter more than nectar or berries because they represent the densest, most energy-rich food source for nesting birds. A single caterpillar contains roughly the caloric equivalent of six blueberries — and unlike berries, caterpillars are available in exactly the period, late spring and early summer, when nestlings are growing fastest and parents have the highest nutritional demands.
Tallamy’s landmark study with Karen Shropshire analyzed 793 lepidopteran species in the mid-Atlantic US and found that the top 14% of plant genera supported 90% of caterpillar species. Five plant genera — oaks, wild cherries, willows, birches, and poplars — supported more caterpillar species than all shrubs, perennials, and grasses in the study combined. Keystone plants are not rare or exotic; they are the foundational trees and shrubs of North American forests that once dominated the continent and have been steadily replaced by non-native ornamentals in suburban landscapes over the past century.
A 2020 follow-up study expanded the analysis to 17 states and confirmed a consistent pattern: just 5% of plant genera in any region support 75% or more of local caterpillar species. The specific top genera shift somewhat by region — blue oaks are keystone trees in California, bald cypress in the Gulf South — but the principle holds everywhere. Prioritize the top-ranked genera in your specific region, and you provide food for the vast majority of local wildlife.
Why Keystone Plants Outperform Non-Native Ornamentals
The reason native keystone plants support so many more species than non-native ornamentals comes down to millions of years of co-evolution. Insects and plants evolved alongside each other — each insect species adapting to the chemical defenses of specific plant families, developing the enzymes needed to break down particular toxins, and timing their life cycles to the leaf-out schedules of specific trees. These relationships are deeply specialized and cannot be replicated overnight.
Many of the most common ornamental landscape trees — Bradford pear, crape myrtle, Norway maple, Japanese flowering cherry — were introduced to North America within the last 200 to 300 years. Local insects simply have not had enough evolutionary time to adapt to their chemical profiles. A Bradford pear (Pyrus calleryana) supports around 9 caterpillar species in North America. A wild black cherry (Prunus serotina) growing in the same garden supports 456. The pear blooms beautifully in spring, but ecologically it is a desert.
Non-native plants also tend to lack the structural complexity that wildlife needs. Native oaks produce acorns consumed by more than 100 vertebrate species — deer, turkeys, squirrels, blue jays, wood ducks, black bears. Their bark hosts thousands of overwintering insect eggs and pupae. Their hollowing trunks provide nesting cavities for screech owls, woodpeckers, and flying squirrels. Their leaf litter, broken down by specialist fungi and invertebrates, creates the rich organic layer where ground-foraging birds — towhees, hermit thrushes, fox sparrows — find the majority of their autumn and winter food. No single non-native ornamental approaches this level of ecological generosity.
The practical implication for gardeners is direct: replacing even one non-native tree or large shrub with a keystone native meaningfully changes the wildlife value of a property. You don’t need acres of wild land. A single oak in a suburban backyard, surrounded by a supporting layer of native shrubs and wildflowers, creates a functional wildlife habitat island. For broader strategies on designing a garden that welcomes wildlife at every level, our complete wildlife garden guide covers habitat structures, water features, and seasonal management alongside plant selection.
Top Keystone Trees: The Wildlife Powerhouses
If you can add only one group of plants for wildlife, add trees — specifically, the keystone tree genera below. These are long-term investments that support exponentially more wildlife than any annual or perennial planting, and many will outlive the gardener who plants them.
Oaks (Quercus spp.) — The Ultimate Keystone Plant
No plant genus in North America supports more wildlife than oaks. Eastern oaks top the list with 534 caterpillar species; even in the lower-diversity western US, oaks routinely support 150 to 200 specialist species. For birds specifically, oaks are irreplaceable: the acorn crop feeds more than 100 vertebrate species, and the caterpillar load on oaks directly determines breeding success for at least 45 local songbird species wherever oaks grow. Strong keystone choices for US gardens include white oak (Quercus alba, zones 3–9), bur oak (Q. macrocarpa, zones 3–8, exceptional in the Midwest and Great Plains), and live oak (Q. virginiana, zones 7–10) for the South. For smaller gardens, chinkapin oak (Q. muehlenbergii, zones 4–7) or Shumard oak (Q. shumardii, zones 5–9) reach manageable proportions while still delivering exceptional ecological returns.
Wild Cherries and Chokecherries (Prunus spp.) — 456 Species
The native cherries — black cherry (Prunus serotina), chokecherry (P. virginiana), wild plum (P. americana), and sand cherry (P. pumila) — are the second most productive keystone tree genus in North America. Beyond caterpillars, the fruit of black cherry is consumed by more than 33 bird species, including cedar waxwings, eastern bluebirds, scarlet tanagers, and great crested flycatchers. Black cherry (Prunus serotina, zones 3–9) is the most widely adaptable and ecologically productive; it can be managed as a large multi-stemmed shrub or allowed to develop into a 60-foot canopy tree. Chokecherry (P. virginiana, zones 2–7) is the better choice for cold climates and provides near-identical wildlife value at a smaller mature size.
Willows (Salix spp.) — 455 Species and Critical Spring Pollen
Native willows are among the most underappreciated keystone plants in American gardens. Their catkin pollen is among the earliest available to queen bumblebees and specialist native bees emerging in late February and March — making willows doubly critical for early pollinator survival as well as caterpillar production. Pussy willow (Salix discolor, zones 4–8) is manageable in most home gardens and provides some of the earliest spring pollen of any native woody plant. Black willow (Salix nigra, zones 2–8) is the most widely distributed native species and outstanding for wet or rain garden sites. Sandbar willow (Salix interior, zones 3–7) can be coppiced regularly to maintain a compact, shrub-like form while still supporting hundreds of specialist insects.
River Birch and Birches (Betula spp.) — 413 Species
Native birches are among the most ecologically productive trees for northern US gardens. River birch (Betula nigra, zones 4–9) is the most broadly adaptable — tolerating both wet and average garden soils, managing heat and humidity into zone 9, and providing winter interest with its exfoliating, salmon-to-cream bark. Yellow birch (Betula alleghaniensis, zones 3–6) and paper birch (B. papyrifera, zones 2–6) are outstanding for colder climates and form the productive backbone of northern forest ecosystems. Birch seeds — tiny, produced in abundance, and persistent through winter — are eaten by redpolls, pine siskins, American goldfinches, and black-capped chickadees, making birches a dual-function keystone that feeds both caterpillar-eating and seed-eating birds.
Top Keystone Shrubs for the Wildlife Garden
After keystone trees, the most productive investment is in native keystone shrubs — the middle layer that provides structure, nesting cover, and additional food below the tree canopy. These species bridge the vertical space between the ground and the canopy, and many begin contributing wildlife food within one to three years of planting.
Native Blueberries (Vaccinium spp.) — The Multi-Purpose Keystone
Native blueberries are arguably the most ecologically efficient shrub you can grow. Vaccinium species support 288 caterpillar species, produce fruit eaten by more than 50 bird species, and supply essential early-season nectar to specialist mining bees (Andrena spp.) that are nutritionally dependent on ericaceous flowers in the genus. For most US gardens, highbush blueberry (Vaccinium corymbosum, zones 4–7), lowbush blueberry (V. angustifolium, zones 3–6), or rabbiteye blueberry (V. virgatum, zones 7–9) are the most productive choices. An added benefit: the same plants that build your wildlife garden produce edible fruit for the gardener. Plant at least two to three varieties for cross-pollination and a longer fruiting season.
Native Viburnums (Viburnum spp.) — Fruit That Persists Through Winter
Native viburnums combine solid caterpillar support (approximately 100 specialist species) with fruit that persists well into winter — a critical food source for migrating and overwintering birds when other foods are exhausted. Arrowwood viburnum (Viburnum dentatum, zones 3–8) is the most adaptable and consistent fruiter, with berries that eastern bluebirds, American robins, and cedar waxwings rely on in late autumn. Blackhaw (V. prunifolium, zones 3–9) produces the heaviest fruit crop and tolerates drier soils than most viburnums. Highbush cranberry (V. trilobum, zones 2–7) is essential in northern gardens and one of the few shrubs whose fruit persists through hard winters when other food sources have failed completely.
Elderberry (Sambucus canadensis) — The Fastest-Establishing Keystone
American elderberry (Sambucus canadensis, zones 3–9) may be the most productive shrub you can establish quickly. It grows rapidly — often 5 to 10 feet in the first two years from a small plant — and begins bearing fruit within one to two seasons of planting. The berries are consumed by 43 bird species including gray catbirds, brown thrashers, eastern bluebirds, rose-breasted grosbeaks, and indigo buntings. The flat-topped flower clusters provide a critical late-June nectar source for native bees, and the hollow piths provide nesting cavities for small carpenter bees. Plant two or more individuals for cross-pollination; elderberry spreads by suckers and can be managed as a productive hedgerow.
Buttonbush (Cephalanthus occidentalis) — The Wetland Keystone
If your garden includes a wet area, rain garden, or pond margin, buttonbush (Cephalanthus occidentalis, zones 5–9) is a keystone choice with few peers. Its fragrant white spherical flowers bloom in midsummer — a gap in many garden flowering calendars — and attract an exceptional diversity of native bees, swallowtail butterflies, and hummingbird moths. Waterfowl consume the seeds, and wood ducks, prothonotary warblers, and other cavity-nesting birds use mature specimens. Buttonbush tolerates prolonged seasonal flooding, making it valuable in low-lying areas where few other shrubs will establish.
Top Keystone Perennials and Wildflowers
Trees and shrubs form the ecological backbone of a keystone garden, but native perennials and wildflowers fill the ground layer with color, seasonal movement, and essential late-season food. These plants provide nectar and seeds from midsummer through winter, and their stems and seed heads provide overwintering habitat for the insects that form next year’s food supply.
Goldenrods (Solidago spp.) — The Most Productive Wildflower
Goldenrods are frequently blamed for hay fever — incorrectly. The real culprit is ragweed (Ambrosia spp.), which blooms at the same time but produces lightweight wind-dispersed pollen. Goldenrod pollen is heavy and sticky, requiring insects for dispersal. Goldenrods support 115 caterpillar species and over 100 specialist bee species, and their seeds feed American goldfinches, dark-eyed juncos, and chipping sparrows from October through March. Stiff goldenrod (Solidago rigida, zones 3–8) and wrinkle-leaf goldenrod (S. rugosa, zones 4–9) are among the most productive garden species. Showy goldenrod (S. speciosa, zones 3–8) offers a more upright, refined form that pairs beautifully with native grasses and asters in a prairie-style border.
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→ View My Garden CalendarNative Asters (Symphyotrichum spp.) — The Monarch’s Autumn Refueling Station
Native asters bloom in late summer and autumn — precisely when monarch butterflies, painted ladies, and dozens of migrating native bee species need fuel for their journeys south. Symphyotrichum species support 112 caterpillar species and are among the most important plant genera for native bees across the autumn season. New England aster (Symphyotrichum novae-angliae, zones 4–8) is the showiest and most productive — its deep purple flowers with golden centers attract monarchs reliably, and it can reach 4 to 6 feet tall in good conditions. For smaller gardens or front borders, aromatic aster (S. oblongifolium, zones 3–8) stays compact at 1 to 2 feet and blooms for six to eight weeks through autumn.
Milkweeds (Asclepias spp.) — The Monarch’s Only Host Plant
Milkweeds hold a unique position in the keystone plant world: they are the only plants on which monarch butterflies can lay their eggs, because they are the only plants that monarch caterpillars are able to eat. The catastrophic decline in North American monarch populations — down more than 80% since the 1990s — tracks closely with the loss of milkweed from agricultural landscapes through herbicide use. Every milkweed plant in a home garden represents a measurable contribution to monarch conservation. Common milkweed (Asclepias syriaca, zones 3–9) is the most productive monarch host. Butterfly weed (A. tuberosa, zones 3–9) offers showier orange flowers and compact form. Swamp milkweed (A. incarnata, zones 3–6) thrives in wet or rain garden sites. Plant three or more species together to extend the season and improve habitat quality.
Native Sunflowers (Helianthus spp.) — The Goldfinch’s Pantry
Native perennial sunflowers do double duty in the wildlife garden: they support 73 caterpillar species as larval hosts, and their seeds are the preferred food of American goldfinches, black-capped chickadees, pine siskins, and house finches through the cold season. Unlike cultivated annual sunflowers, native perennial species — swamp sunflower (Helianthus angustifolius, zones 6–9), Maximilian sunflower (H. maximiliani, zones 4–9), and woodland sunflower (H. divaricatus, zones 3–8) — return reliably each year and slowly spread to form increasingly productive colonies. Leave the seed heads standing through winter and you will have feeding goldfinches in your garden from October through February without a supplemental feeder.
Native Violets (Viola spp.) — The Fritillary Foundation
Native violets are the host plants for 29 species of fritillary butterflies — among the most spectacular butterfly species in North America, including the great spangled fritillary, regal fritillary, and Diana fritillary. Common blue violet (Viola sororia, zones 3–9) and arrow-leaved violet (V. sagittata, zones 3–8) are the most widely available and ecologically productive. Allow them to naturalize in lawn edges, under shrubs, and in shaded areas; their low growing habit means they integrate seamlessly as a living ground cover without competing with taller plants.
Keystone Plants by USDA Zone
| Region & Zone | Top Keystone Trees | Top Keystone Shrubs | Top Keystone Perennials |
|---|---|---|---|
| Zones 2–4 Northern Plains, upper Midwest, northern New England | Bur oak, paper birch, chokecherry, trembling aspen | Pussy willow, highbush cranberry viburnum, lowbush blueberry | Prairie goldenrod, New England aster, common milkweed |
| Zones 5–6 Mid-Atlantic, Midwest, Pacific Northwest interior | White oak, black cherry, river birch, swamp white oak | Arrowwood viburnum, highbush blueberry, elderberry | Wrinkle-leaf goldenrod, New England aster, butterfly weed, swamp milkweed |
| Zones 7–8 Upper South, Pacific Northwest coast, Mid-Atlantic coast | Shumard oak, black cherry, sweetbay magnolia, tulip poplar | Rabbiteye blueberry, buttonbush, native azalea (Rhododendron spp.) | Swamp sunflower, aromatic aster, rose milkweed, Gulf Coast goldenrod |
| Zones 9–10 Deep South, California, Gulf Coast | Live oak, water oak, bald cypress, coast live oak (CA) | Wax myrtle, beautyberry, native spiderwort | Gulf Coast goldenrod, blue mistflower, tropical sage, native passionvine |
How to Build a Keystone Garden: A Step-by-Step Plan
You don’t need to transform your entire landscape at once. The most effective approach is to start with one keystone tree, then build out the supporting layers over several seasons. This is the framework Dr. Tallamy and other ecologists consistently recommend for home gardeners working within typical suburban constraints.
Step 1: Start with the anchor tree. Choose the most ecologically productive keystone tree appropriate to your zone — for most US gardeners, this means an oak. Plant it where it has room to reach its mature size over the coming decades. Even a 2-foot seedling will begin supporting caterpillars in its first season. The tree is your most important long-term investment; everything else can be adjusted around it as the garden develops.
Step 2: Build the shrub layer around the tree’s drip line. Native viburnums, blueberries, and elderberry positioned beneath or near the tree canopy create a productive middle layer that provides nesting cover and additional food. The leaf litter accumulating under these shrubs shelters overwintering moth eggs, beetle larvae, and insect pupae — the exact food that ground-foraging birds like towhees, thrushes, and fox sparrows search for in autumn and winter. Maintaining a deep wood-chip mulch layer in this zone, as detailed in our complete mulching guide, mimics the forest floor and retains the moisture that shrub roots need to establish.
Step 3: Add the wildflower layer in the sunny edges. Goldenrods, asters, and milkweeds planted in the sunnier margins of your keystone garden provide color from May through November and feed a continuous succession of pollinators and insects. Native violets, wild ginger, and woodland strawberry fill the shadier areas closer to the tree trunk as a living ground cover that protects the soil and shelters ground beetles and beneficial insects.
Step 4: Connect to the wider landscape. Isolated habitat islands have limited value for wildlife that must move between them to find food, mates, and shelter. Where possible, create corridors — hedgerows of native shrubs along fence lines, street tree plantings, or native plantings in parking strip areas — that link your garden to a neighbor’s garden or to a nearby park or wild area. Replacing turf with productive native plantings is one of the highest-impact landscape decisions a gardener can make; our lawn alternatives guide covers the full range of ground-level alternatives that replace grass with functional native habitat.
Step 5: Leave the “mess” in autumn. Between 90 and 95% of North American moth species overwinter as eggs, pupae, or adults in the leaf litter and soil beneath garden plants. Removing leaf litter in autumn or blowing it away removes this overwintering habitat and directly crashes the food web that supports birds the following spring. Leave leaves under trees and shrubs; rake only paths and lawn areas where accumulation is genuinely problematic. Leaving goldenrod and aster stems standing through winter also provides stem-nesting habitat for 30% of native bee species that overwinter in hollow or pithy plant stems.
If your landscape currently contains invasive ornamentals like burning bush, Japanese barberry, or Bradford pear, removing and replacing them is a high-priority first step before adding new keystone species. Our guide to replacing invasive ornamentals with native keystone plants covers identification, safe removal techniques, and zone-by-zone replacement recommendations for each species.
Common Mistakes When Choosing Keystone Plants
Choosing cultivars with visually altered traits. A cultivar like ‘Autumn Brilliance’ serviceberry or a dark-leaved elderberry may be genetically derived from a native plant, but selective breeding for traits like unusual leaf color, double flowers, or extended bloom time can significantly reduce ecological value. Double-flowered cultivars produce little or no pollen; dark-leaved or variegated cultivars may be harder for specialist insects to recognize. Where possible, use straight native species, or cultivars selected only for site adaptability rather than visual novelty.
Planting a single species rather than a diverse community. Even oaks are more ecologically valuable when grown alongside other keystone species. Aim for at least five to seven different native plant species in any planting to provide seasonal food from the first willow catkins in March through autumn goldenrod seeds, and structural diversity that offers multiple nesting opportunities and microhabitats.
Treating caterpillar damage as a problem to solve. Chewed leaves are the sign of a functioning keystone garden, not a failing one. If your black cherry has caterpillars, those caterpillars are producing exactly the food that nearby birds need for their nestlings. Resist the urge to spray or remove the “damage.” Holes in leaves are evidence that your keystone garden is working as designed.
Sourcing plants from outside your local genetic provenance. A white oak grown from acorns collected in Georgia may be less well-adapted — and potentially less useful to local specialist insects — than one grown from Pennsylvania seed stock. Look for local ecotype plants from reputable native plant nurseries, regional native plant society sales, or seed exchanges within 100 miles of your garden. The difference in adaptation and long-term wildlife support can be substantial.
Frequently Asked Questions
Do keystone plants only benefit caterpillars and birds?
No — caterpillar data is used as the primary metric because it is the most comprehensively researched, but keystone plants also support far more native bee species, specialist beetles, gall wasps, and other invertebrates than non-native ornamentals. An oak alone is associated with at least 80 specialist cynipid gall wasp species, dozens of specialist mining bees, and hundreds of fungal species in its root zone. The ecological relationships extend far beyond caterpillars and birds into every corner of the soil food web.
Can I have a tidy, designed garden and still use keystone plants?
Yes. The keystone plant concept is about plant selection, not garden style. A formal garden with structured edges can incorporate an oak as a focal canopy, goldenrods in a cut-flower patch, and native asters in a mixed border. The ecological value derives from the plant choices, not the design aesthetic. The one non-negotiable element: avoid aggressively removing leaf litter and standing stems in autumn, which eliminates the overwintering habitat that sustains the food web into the following spring.
What if I don’t have space for a large oak?
Choose a smaller keystone tree — chinkapin oak (Quercus muehlenbergii), dwarf chestnut oak (Q. prinoides), or a native serviceberry (Amelanchier spp., supporting 124 caterpillar species) as a large shrub or small tree. Or focus on the shrub and perennial layers: a garden of native blueberries, viburnums, goldenrods, asters, and milkweeds is ecologically far superior to a conventional ornamental garden even without a canopy tree.
How quickly do keystone plants establish and produce results?
Goldenrods, asters, and milkweeds support wildlife in their first season. Elderberry and native viburnums typically fruit within two to three years. Oaks and birches take longer — 10 to 20 years to reach significant canopy coverage — but a 5-year-old oak already supports dozens of caterpillar species. The right mindset: plant oaks now, enjoy the wildflowers immediately, and allow the garden to deepen in ecological value with each passing year.
Where can I find locally sourced native plants?
The Xerces Society and the Lady Bird Johnson Wildflower Center both maintain directories of native plant nurseries organized by state. Local native plant societies often hold spring plant sales that are excellent sources of locally sourced ecotypes. Avoid purchasing “native” plants from big-box retailers, where provenance is rarely documented and plants are frequently treated with systemic neonicotinoid pesticides that persist in plant tissue and harm the insects they are supposed to attract.
Keystone Plants by Region: In-Depth Guides
For detailed plant lists matched to your specific region, hardiness zones, and local conditions, see our regional keystone plant guides:
- Keystone Plants for the Northeast — Zones 4–7, New England and Mid-Atlantic (ME, NH, VT, MA, RI, CT, NY, NJ, PA, MD, DE, DC, WV, VA)
- Keystone Plants for the Midwest — Zones 4–6, Great Lakes and Prairie states
- Keystone Plants for the Southeast — Zones 6–9, Gulf Coast to Appalachian gardens
- Keystone Plants for the West — Zones 5–10, Pacific Coast, Mountain West, and Southwest
Sources
- Tallamy, D.W. Home Grown National Park — The Science Behind Keystone Plants for Wildlife. HomeGrownNationalPark.org
- Xerces Society for Invertebrate Conservation. Native Plants and Pollinator Habitat Resources. Xerces.org
- National Wildlife Federation. Native Plants: How Planting Native Helps Wildlife. NWF.org
- Lady Bird Johnson Wildflower Center. Native Plant Database and Regional Growing Guides. Wildflower.org
