What To Plant To Improve Biodiversity In Iowa Garden Design

Iowa sits in a transition zone between tallgrass prairie, savanna, and eastern deciduous forest. That diversity of natural communities means that gardeners have many options to increase biodiversity on even small urban or suburban lots. Thoughtful plant choice and simple habitat features can turn a conventional lawn or ornamental bed into a living landscape that supports pollinators, birds, beneficial insects, soil life, and native plant communities.
This article outlines specific species, planting strategies, seasonal considerations, and practical maintenance tips tailored to Iowa climates and soils. The goal is concrete guidance you can use to select, place, and manage plants that improve ecological function while remaining attractive and manageable.

Principles for Biodiverse Iowa Garden Design

Start with a few guiding principles that shape species selection and layout.

Favor native species adapted to Iowa climate and soils; they require less water and support more native insects and birds.
Provide structural diversity: canopy trees, understory shrubs, perennial flowers, grasses, and groundcovers.
Ensure season-long resources: early nectar and pollen, midseason abundance, and late-season blooms and seeds.
Include host plants for butterfly and moth larvae, not just nectar sources for adults.
Reduce disturbance: leave some standing dead stems, leaf litter, and bare ground for cavity-nesting bees and overwintering insects.
Minimize pesticides and use integrated pest management when necessary.

Native Trees and Large Woody Plants (Canopy and Subcanopy)

Trees form the backbone of habitat in any landscape. Select species that produce Flowers, fruit, or nuts that feed wildlife, and that host diverse caterpillar communities.

Recommended canopy and subcanopy trees

Bur oak (Quercus macrocarpa) – a prairie-savanna oak adapted to Iowa soils; hosts many moth and butterfly caterpillars and produces acorns for birds and mammals.
White oak (Quercus alba) – supports high insect biodiversity and is a keystone genus for wildlife.
Hackberry (Celtis occidentalis) – supports dozens of butterfly and moth species; fruit eaten by birds.
Black cherry (Prunus serotina) – early spring flowers for pollinators; cherries feed birds.
Eastern redbud (Cercis canadensis) – early spring flowers valuable to bees.
Black walnut (Juglans nigra) – produces nuts for wildlife; large canopy tree.

Plant trees in groups or lines to create habitat corridors instead of isolated specimens. When space is limited, choose smaller native trees such as serviceberry (Amelanchier spp.) that provide early flowers and fruit for birds.

Shrubs and Small Trees (Food, Shelter, and Layering)

Shrubs are vital for nesting, cover, and fruit. They bridge canopy and herbaceous layers.

Recommended shrubs

Serviceberry (Amelanchier arborea) – spring flowers and summer berries.
American hazelnut (Corylus americana) – catkins for early pollen; nuts for wildlife.
Buttonbush (Cephalanthus occidentalis) – great for rain gardens and wet areas; pollinator magnet.
Ninebark (Physocarpus opulifolius) – attractive flowers and nesting cover.
Elderberry (Sambucus canadensis) – late-summer berries for birds and mammals.
New Jersey tea (Ceanothus americanus) – nitrogen-fixing shrub that supports native bees.

Group shrubs in thickets to provide nesting sites and protective cover for small birds and mammals.

Native Grasses and Sedges (Structure and Habitat)

Native grasses form the framework of prairie and savanna planting. They provide seed for birds, nesting structure, and winter habitat for insects.

Big bluestem (Andropogon gerardii) – tall, architectural grass for prairies.
Little bluestem (Schizachyrium scoparium) – good for borders and supports beneficial insects.
Switchgrass (Panicum virgatum) – adaptable and provides winter structure.
Indian grass (Sorghastrum nutans) – upright form and seed heads attractive to birds.
Native sedges (Carex spp.) – use in moist or shady spots; support specialist insects.

Plant grasses in drifts, not single clumps, to mimic natural prairie patterns and increase visual impact.

Forbs and Wildflowers (Nectar, Pollen, and Host Plants)

Focus on a mix of early, mid, and late-season bloomers and include species that are host plants for butterfly and moth caterpillars.

Early-season bloomers (March-May)

Pussy willow or Salix species – among the earliest pollen sources for bees.
Serviceberry (Amelanchier) – spring flowers for bees and flies.
Wild columbine (Aquilegia canadensis) – spring nectar for hummingbirds and bumblebees.
Spring ephemerals (Trillium, Claytonia) in shady beds.

Mid-season bloomers (June-August)

Purple coneflower (Echinacea purpurea) – nectar and seedheads for birds.
Black-eyed Susan (Rudbeckia hirta) – prolific nectar source.
Wild bergamot (Monarda fistulosa) – mint family; attracts bees and butterflies.
Blazing star (Liatris spp.) – late-mid season nectar for butterflies.

Late-season bloomers (August-October)

Goldenrod (Solidago spp.) – vital late-season nectar source for bees and butterflies.
Asters (Symphyotrichum spp.) – feed late migrating monarchs and bees.
Joe-Pye weed (Eutrochium purpureum) – large bloom for butterflies and bees.

Important host plants

Common milkweed (Asclepias syriaca), swamp milkweed (Asclepias incarnata), and butterfly milkweed (Asclepias tuberosa) – critical for monarch butterfly larvae.
Willow (Salix spp.), poplar, and cottonwood – hosts for viceroy and other moths.
Cherry and willow species – hosts for swallowtails and many moth larvae.
Goldenrod and asters – host plants for numerous caterpillars.

Designing for Season-Long Resources

A biodiverse garden must feed wildlife from early spring through late fall.

Include early pollen sources: willows, redbud, and spring bulbs or ephemerals.
Plant abundant mid-summer nectar producers: monarda, echinacea, rudbeckia.
Reserve substantial late-season bloom: goldenrods and asters; these power migrating pollinators and pre-winter feeding.

Group plants by bloom time and family to create dense nectar patches that are easier for pollinators to find.

Practical Planting and Establishment Tips

Successful establishment matters. Follow these practical steps for long-term biodiversity benefits.

Soil and site: Match plants to site moisture and light conditions. Prairie plants do best in well-drained sun; switch to sedges and wetland species for low-lying soggy areas.
Planting time: Fall sowing of native prairie seed mixes often gives the best germination after natural cold stratification. Spring planting of plugs is practical for gardens.
Seed vs. plugs: Seed mixes are cost-effective for larger areas. Plugs or container-grown perennials give faster visual structure and are easier to weed during establishment.
Mulch and lawn removal: Remove turf in the planting area. For native plugs, use a thin layer of organic mulch sparingly; avoid thick wood mulch over areas where ground-nesting bees may operate.
Avoid excessive fertilizer: Native prairie and meadow plants evolved with low soil fertility. High fertility favors aggressive nonnative species and reduces diversity.

Maintenance for Biodiversity

Biodiverse plantings require different maintenance than ornamental beds.

Mowing and cutting regimes: For meadows, mow in late winter or very early spring after birds and insects have used seed and stems for shelter. Avoid fall mowing to preserve overwintering habitat.
Selective invasive control: Remove invasive shrubs like buckthorn and nonnative honeysuckles promptly. Cut and treat stumps if necessary.
Reduce pesticides: Broad-spectrum insecticides kill pollinators and beneficial predators. Use targeted controls only when necessary and prefer mechanical or biological options.
Leave some dead wood and stems: Brush piles, standing dead stems, and leaf litter are critical for insect life cycles and cavity-nesting birds.

Habitat Features Beyond Plants

Water: A shallow birdbath with a sloped edge or a small pond supports drinking and bathing. Provide mud puddles for butterfly puddling.
Nesting sites: Leave bare soil patches for ground-nesting bees and retain snags or install native bee houses for cavity dwellers.
Brush piles: Use pruned branches to create temporary brush piles for shelter and small mammal habitat.
Hedgerows and corridors: Connect garden patches with hedgerows of native shrubs to allow wildlife movement across urban landscapes.

Plants to Avoid and Invasives to Remove

Some commonly sold or gardened species reduce biodiversity and crowd out natives.

Common buckthorn (Rhamnus cathartica) – invasive, forms dense thickets.
Amur honeysuckle (Lonicera maackii) – shades out native understory.
Garlic mustard (Alliaria petiolata) – displaces spring ephemerals.
Purple loosestrife (Lythrum salicaria) – invasive in wetlands.

Prioritize removal and replacement of these species with native alternatives listed above.

Sample Planting Palette by Function

Canopy: Bur oak, Hackberry.
Understory: Serviceberry, American hazelnut.
Structural grasses: Big bluestem, little bluestem.
Pollinator perennials: Wild bergamot, purple coneflower, monarda.
Host plants: Common milkweed (monarchs), willows (viceroy), black cherry (swallowtails).
Moist site: Buttonbush, swamp milkweed, sedges.

Actionable Next Steps

Walk your property and map sun, shade, and moisture zones.
Remove concentrated patches of invasive plants and replace them with suitable natives for that zone.
Plan for at least three layers: tree/shrub canopy, shrub/understory, and herbaceous/groundcover.
Plant in groups of single species (drifts) of at least 5 to 7 plants to attract pollinators more effectively.
Keep a written or photographed record of bloom times and wildlife visitors; adapt plant choices in subsequent seasons based on what performs and what wildlife is observed.

Increasing biodiversity in an Iowa garden is both a design challenge and an opportunity. With purposeful plant choices, structural layering, and wildlife-friendly maintenance, a suburban yard can become a functioning habitat corridor that supports pollinators, birds, and a diverse community of native organisms. Start small, observe, and expand–the rewards include richer wildlife sightings, improved ecosystem services, and a resilient, beautiful landscape.