Interior River Valleys and Hills is Ecoregion 8.3.2, located in the central part of the Mississippi basin where large rivers such as the Ohio and Missouri meet the Mississippi River, spanning several states and characterized by wide, flat-bottomed terraced valleys and a severe, mid-latitude, humid continental climate.
Zone
Prairie
Common Name
Interior River Valleys and Hills
CEC Level III Code
8.3.2
CEC Level II Code
8.3 Southeastern USA Plains
Overview
Region facts
| Category | Details |
|---|---|
| Aliases | Interior River Valleys and Hills, CEC 8.3.2, Interior River Valleys & Hills |
| Geographic Range | Ecoregion 8.3.2 is located in the central Mississippi basin where the Ohio and Missouri Rivers meet the Mississippi, spanning southeast Iowa, southwestern and southern Illinois, eastern Missouri, southeastern Indiana, and western Kentucky. |
| Climate Snapshot | Ecoregion 8.3.2 has a severe, mid-latitude, humid continental climate marked by hot summers and cold winters, with a mean annual temperature of 10°C to 14°C and a mean annual precipitation of 1,057 mm. |
| Terrain Profile | The region is characterized by wide, flat-bottomed terraced valleys, valley slopes, and river bluffs, featuring dissected glacial till plains in the north and broad, low gradient valleys in the south. |
| Vegetation Cover | The region is characterized by former extensive bottomland deciduous forests and swamp forests, now largely replaced by cropland and pastureland, alongside remaining mixed oak forests in upland and mesic sites. |
| Wildlife Habitat | The Interior River Valleys and Hills region supports abundant native wildlife including white-tailed deer, raccoon, bobwhite quail, Carolina chickadee, various snakes like the copperbelly water snake and timber rattlesnake, turtles such as the eastern box and snapping turtle, and aquatic life like paddlefish and various darters. |
Eco snapshot
The region is characterized by former extensive bottomland deciduous forests and swamp forests, now largely replaced by cropland and pastureland, alongside remaining mixed oak forests in upland and mesic sites.
The Interior River Valleys and Hills region supports abundant native wildlife including white-tailed deer, raccoon, bobwhite quail, Carolina chickadee, various snakes like the copperbelly water snake and timber rattlesnake, turtles such as the eastern box and snapping turtle, and aquatic life like paddlefish and various darters.
Seasonal timing
Yearly needs
What pollinators need throughout the year, and what to do about it.
| Season | What pollinators need most | What you can do |
|---|---|---|
| Late winter / early spring | Early nectar and pollen; safe places to warm up and forage | Plant/maintain early bloomers; leave some leaf litter and stems; avoid “spring cleanup” that removes shelter |
| Spring | Steady bloom; nesting materials and undisturbed nesting spots | Add a mix of spring flowers; keep some bare, well-drained soil; plant in sunny clumps |
| Summer | Reliable nectar during heat; water access; shade/cover nearby | Add mid-summer bloomers; provide a shallow water dish with stones; mulch thoughtfully (don’t smother all bare soil) |
| Late summer / fall | High-energy nectar for late-season bees and migrating insects; seed/structure | Plant late bloomers; let some plants go to seed; leave stems standing |
| Winter (or dormant season) | Shelter in stems, leaf litter, and ground; protection from disturbance | Leave stalks and “messy” corners; delay heavy pruning; plan next season’s bloom gaps to fill |
Seed mix concept
Spring starter: early bloomers that “wake up” the season and feed emerging bees.
Summer bridge: heat-tolerant, mid-season flowers that keep nectar coming when lawns and many landscapes go quiet.
Fall finisher: late bloomers (often asters/goldenrods in many areas) that provide crucial end-of-season fuel.
What You Can Do
Turn this knowledge into action. Whether you plant a single pot or a whole garden, you are building a vital bridge for local biodiversity.
Join the movement to restore our shared habitats.
Native plants
Asters are late-season wildflowers that bring a burst of daisy-like blooms when many gardens are winding down, making them a reliable choice for pollinator-friendly planting.
Blackberries and raspberries (genus Rubus) are flowering bramble shrubs that can feed pollinators in bloom and people later with tasty berries—great for yards, school gardens, and even large containers with support.
Blazing stars (Liatris) are upright, purple-pink wildflowers that bloom in showy spikes and are well-loved by many pollinators. They’re a strong choice for sunny gardens, borders, and meadow-style plantings.
Blueberries and huckleberries (genus Vaccinium) are berry-producing shrubs with spring flowers that can support pollinators and later feed people and wildlife—great for gardens, schoolyards, and even large containers.
Coneflowers (Echinacea) are tough, long-blooming wildflowers that bring steady color and reliable nectar and pollen to gardens, schoolyards, and even large containers.
Currants and gooseberries are Ribes shrubs that offer early-season flowers for pollinators and later berries for people and wildlife. They’re a great choice for edible landscapes, mixed borders, and small yards where you want a plant that does more than one job.
Goldenrods are tough, sunny wildflowers in the genus Solidago that light up late-season gardens with golden blooms and provide reliable nectar and pollen when many other flowers are fading.
Ironweeds are tall, purple-blooming wildflowers in the genus Vernonia that bring late-season color and steady nectar to pollinator gardens.
Joe-Pye weeds are tall, late-season native wildflowers in the genus Eutrochium that bring big, fluffy flower clusters to gardens and give pollinators a reliable place to feed when many other plants are winding down.
Maples are familiar shade trees that offer early-season flowers and later seeds, supporting a range of pollinators and adding strong structure to yards, school grounds, and streetscapes.
Milkweeds are tough, nectar-rich wildflowers in the genus Asclepias that can turn a garden bed, schoolyard edge, or even a sunny pot into a pollinator stop.
Mountain mints are tough, fragrant native wildflowers that bloom in summer and are famous for drawing in a busy mix of pollinators. They’re easy to grow, handle a range of garden conditions, and make a great “plant it and watch it” choice for pollinator patches.
Oaks are long-lived trees that can anchor a yard, school ground, or park with shade, structure, and lots of seasonal interest. Many pollinators use oak flowers in spring, and the tree’s leaves and bark support a wide web of life over time.
Prairie coneflowers (Ratibida) are tough, sunny wildflowers with drooping petals and a bold cone-shaped center that pollinators can easily find. They’re a great choice for low-fuss gardens, schoolyards, and naturalized patches where you want long-lasting summer color.
Rushes are tough, grass-like wetland plants (genus Juncus) that thrive in damp soil and help create calm, sheltered habitat at the edges of ponds, rain gardens, and low spots.
Sedges (genus Carex) are grass-like plants that form tidy clumps and thrive in many garden conditions, especially where soil stays a bit damp. They add texture, cover bare ground, and can support small wildlife by providing shelter and nesting material.
Serviceberries (genus Amelanchier) are small trees with early-season blossoms, edible berries, and strong wildlife value—an easy way to add beauty and pollinator support to a yard, school garden, or even a large container.
Native sunflowers are bright, tough wildflowers in the genus Helianthus that feed pollinators and add cheerful color from mid-season into fall.
Wild bergamot and other bee balms (the genus Monarda) are easygoing native wildflowers known for their shaggy, pom‑pom blooms that draw in lots of pollinators. They’re a great choice when you want long-lasting summer color and a plant that feels lively with buzzing visitors.
Willows are fast-growing trees and shrubs in the genus Salix that offer some of the earliest pollen and nectar of the year, making them a strong choice for pollinator-friendly yards, parks, and school grounds.
Pollinators
Adults visit flowers for nectar and can move pollen between blooms; their presence is a sign of diverse, functioning habitats.
Many brushfoots move pollen between flowers as they feed, and their caterpillars are part of healthy food webs.
Bumble bees are important pollinators of many wildflowers and garden plants, helping ecosystems and food crops reproduce.
Adults visit flowers for nectar and pollen, and many species’ larvae help keep plant-eating pests in check.
They can move pollen between flowers while feeding on nectar, especially for blooms that open or scent up in the evening.
They move pollen between flowers while foraging, helping many wild plants and garden plants set seed and fruit.
They move pollen between flowers while foraging, helping many wild plants and garden crops set seed and fruit.
They move pollen between flowers while foraging, helping many wild plants and garden plants set seed and fruit.
They can move pollen while drinking nectar, and they also help control many plant-eating insects.
They’re part of healthy food webs and plant communities, and their caterpillars depend on a wide range of native trees and shrubs.
Skippers visit many flowers for nectar and can help move pollen between blooms while they feed.
Many small moths move pollen while feeding on nectar, supporting wild plants and garden blooms—especially in the evening and at night.
Many adults visit flowers and can move pollen between blooms, while also helping control some garden pests.
Adult swallowtails visit many flowers for nectar and can help move pollen between blooms as they feed.
They help move pollen between flowers in gardens, parks, and natural areas, supporting seed and fruit production.
They visit a wide range of flowers for nectar and can help move pollen between blooms as they feed.
