# Companion species

> Pick one native tree or shrub and see the species that share its ground in the wild, live under its canopy, or want the same sun, soil and climate in a yard.

Blue Whale Trees, a native tree nursery in the United States. Web version: https://bluewhaletrees.com/tools/companions/?species=missouri-river-willow

Try [black walnut](https://bluewhaletrees.com/tools/companions/index.html.md?species=black-walnut), [flowering dogwood](https://bluewhaletrees.com/tools/companions/index.html.md?species=flowering-dogwood) or [spicebush](https://bluewhaletrees.com/tools/companions/index.html.md?species=spicebush).

Pick one native tree or shrub and see what grows with it. The matches come in three groups. Some species share its ground in the wild, and others live under its canopy or are the trees it can be planted beneath. The rest suit the same yard because they want the same sun, soil and climate. Every match is explained on the page, so you can see why a species is listed.

## [Missouri River Willow](https://bluewhaletrees.com/plants/missouri-river-willow/index.html.md) grows in stream banks, floodplain forests, swamps and wet flats, old fields and edges

These natives share that ground, so they will look right together and want the same care.

- [American Elm](https://bluewhaletrees.com/plants/american-elm/index.html.md) (*Ulmus americana*): Large tree, 60–80 ft
- [Slippery Elm](https://bluewhaletrees.com/plants/slippery-elm/index.html.md) (*Ulmus rubra*): Medium tree, 40–70 ft · shares stream banks, floodplain forests, old fields and edges
- [Common Hackberry](https://bluewhaletrees.com/plants/common-hackberry/index.html.md) (*Celtis occidentalis*): Large tree, 40–60 ft · shares stream banks, floodplain forests, old fields and edges
- [Cockspur Hawthorn](https://bluewhaletrees.com/plants/cockspur-hawthorn/index.html.md) (*Crataegus crus-galli*): Small tree, 20–30 ft · shares stream banks, floodplain forests, old fields and edges
- [River Birch](https://bluewhaletrees.com/plants/river-birch/index.html.md) (*Betula nigra*): Medium tree, 40–70 ft · shares stream banks, floodplain forests, swamps and wet flats
- [Black Gum (Tupelo)](https://bluewhaletrees.com/plants/black-gum/index.html.md) (*Nyssa sylvatica*): Large tree, 40–70 ft · shares floodplain forests, swamps and wet flats, old fields and edges
- [Swamp White Oak](https://bluewhaletrees.com/plants/swamp-white-oak/index.html.md) (*Quercus bicolor*): Medium tree, 50–60 ft · shares stream banks, floodplain forests, swamps and wet flats
- [Pin Oak](https://bluewhaletrees.com/plants/pin-oak/index.html.md) (*Quercus palustris*): Large tree, 50–70 ft · shares stream banks, floodplain forests, swamps and wet flats

How far apart: the [planting-distance tool](https://bluewhaletrees.com/tools/distance/index.html.md?species=missouri-river-willow&near=tree) gives the gap between Missouri River Willow and any tree you name as the next one, by their pages' spacing or half of each crown, added.

## Beside it

Plants that want the same sun and soil, for a bed, a hedge or a grove.

- [Buttonbush](https://bluewhaletrees.com/plants/buttonbush/index.html.md) (*Cephalanthus occidentalis*): Shrub, Zones 4–10, 5–12 ft, Price on request. Shares stream banks, floodplain forests, swamps and wet flats in the wild. Hardy in zones 4 to 9 of the Missouri River willow's 3 to 9.
- [Wild Black Currant](https://bluewhaletrees.com/plants/wild-black-currant/index.html.md) (*Ribes americanum*): Shrub, Zones 3–7, 3–6 ft, Price on request. Shares stream banks, floodplain forests, swamps and wet flats in the wild. Hardy in zones 3 to 7 of the Missouri River willow's 3 to 9.
- [Red Osier Dogwood](https://bluewhaletrees.com/plants/red-osier-dogwood/index.html.md) (*Cornus sericea*): Shrub, Zones 2–7, 6–12 ft, Price on request. Shares stream banks, floodplain forests, swamps and wet flats in the wild. Hardy in zones 3 to 7 of the Missouri River willow's 3 to 9.
- [Bebb's Willow](https://bluewhaletrees.com/plants/bebb-willow/index.html.md) (*Salix bebbiana*): Shrub, Zones 3–7, 10–25 ft, Price on request. Shares stream banks, swamps and wet flats, old fields and edges in the wild. Hardy in zones 3 to 7 of the Missouri River willow's 3 to 9.
- [Possumhaw Viburnum](https://bluewhaletrees.com/plants/possumhaw-viburnum/index.html.md) (*Viburnum nudum*): Shrub, Zones 5–9, 5–12 ft, Price on request. Shares stream banks, floodplain forests, swamps and wet flats in the wild. Hardy in zones 5 to 9 of the Missouri River willow's 3 to 9.
- [Virginia Sweetspire](https://bluewhaletrees.com/plants/virginia-sweetspire/index.html.md) (*Itea virginica*): Shrub, Zones 5–9, 3–6 ft, Price on request. Shares stream banks, floodplain forests, swamps and wet flats in the wild. Hardy in zones 5 to 9 of the Missouri River willow's 3 to 9.
- [When these flower and fruit](https://bluewhaletrees.com/tools/calendar/index.html.md?plants=missouri-river-willow,buttonbush,wild-black-currant,red-osier-dogwood,bebb-willow,possumhaw-viburnum,virginia-sweetspire), in the bloom and fruit calendar.

## Email me when Missouri River Willow or a companion is ready to order

For Missouri River Willow, Buttonbush, Wild Black Currant, Red Osier Dogwood, Bebb's Willow, Possumhaw Viburnum, Virginia Sweetspire, American Elm, Slippery Elm, Common Hackberry, Cockspur Hawthorn, River Birch: one email per plant when it is priced or back in stock, and nothing else. Each carries a code for 10% off the plants in that order, not shipping or tax.

## How the matches are made

- **Natural communities.** Every species we grow is tagged with the communities it lives in: floodplain forests, swamps and wet flats, stream banks, rich moist slopes, dry uplands, sandy barrens, rocky ground, old fields and edges, the forest understory, the Appalachians and the coast.
- **In the wild.** Up to eight natives that share one of those communities with it and grow wild in one of its states. The most communities in common come first, then the native range most like its own. A species in a yard list is not repeated here.
- **Under its canopy, or trees to plant it under.** Up to six species at least two sizes apart, the smaller one taking part shade or shade: shrubs under a medium tree, shrubs and small trees under a large one.
- **Beside it.** Up to six that share a sun with it, the same size first.
- **The order of a yard list.** Every yard pick shares a zone, a soil and a state of native range with it. A shared community counts two points, and a shared sun or soil one. Under a canopy, a species of the forest understory counts two more, and one that takes full shade one more. Of equal scores, the one hardy in more of its zones comes first.
- **How far apart.** Each yard card links the planting-distance tool with both trees named. The tool gives the gap between them: each one's own spacing from its page, or half of each crown added, unless a page gives a larger distance from other trees. The wild list links the same tool with the chosen tree set, for any next tree you name.
- **Your zone.** With a zone chosen, the yard lists keep only species rated hardy in it.
- **Black walnut.** The 45 species we grow that the Morton Arboretum lists as sensitive to its juglone are left out of its answer, and it is left out of theirs. Under a walnut, the species on Morton's tolerant lists come first and are marked.
- **Eastern red cedar.** The 28 crabapples, hawthorns, serviceberries, chokeberries and mountain ash we grow are left out of its answer, and it is left out of theirs: the cedar-apple, hawthorn, quince and juniper broom rusts live on both, and the University of Minnesota Extension says to keep them a few hundred yards apart.
- **A tree or shrub we do not grow.** The 45 common natives under their own group in the menu take the same tests, with their ground, zones, sun, soil and states of native range from their sources (Silvics of North America, the USDA PLANTS Database, the Woody Plant Seed Manual, the Fire Effects Information System and extension and botanical garden pages). The answer says so, links no page, and offers the sign-up for the companions only.

## Common questions

### What can I plant under a black walnut tree?

Under a black walnut, the tool puts first the species on the Morton Arboretum's tolerant lists, such as [pawpaw](https://bluewhaletrees.com/plants/pawpaw/index.html.md), [spicebush](https://bluewhaletrees.com/plants/spicebush/index.html.md) and [flowering dogwood](https://bluewhaletrees.com/plants/flowering-dogwood/index.html.md). It leaves out those Morton lists as sensitive to the walnut's juglone, and Morton warns that any such list is incomplete.

### What should you not plant near a black walnut?

Of the trees and shrubs we grow, the Morton Arboretum lists crabapples, hackberries, lindens, rhododendrons, blueberries, larch, yew and red chokeberry as sensitive to black walnut's juglone. Azaleas count among the rhododendrons, and the tool keeps all of them out of a walnut's answer.

### What can I plant under a big tree?

Under a large tree, the tool lists up to six shrubs and small trees that take part shade or shade, and species of the forest understory rank higher. Our article on [what to plant under a big tree](https://bluewhaletrees.com/articles/what-to-plant-under-a-big-tree/index.html.md) covers planting without hurting the tree.

### Which native trees and shrubs grow together in the wild?

The tool lists up to eight natives that share a natural community with your species and grow wild in one of its states, by the USDA PLANTS Database. The communities are our own tags, and sharing one does not mean two species always grow side by side.

### Can eastern red cedar be planted near crabapples?

The University of Minnesota Extension says not to plant [eastern red cedar](https://bluewhaletrees.com/plants/eastern-red-cedar/index.html.md) within a few hundred yards of crabapples, hawthorns, serviceberries, chokeberries or mountain ash, since cedar-apple and related rusts live on both. The tool keeps them out of each other's answers.

The communities are our own tags. The states of native range are the USDA PLANTS Database's records, read on 2026-09-23 (2026-10-13 for the common natives we do not grow), as the [native trees by state](https://bluewhaletrees.com/tools/native/index.html.md) tool reads them. Zones, sun and soil are each species' own page, or its record for a common native we do not grow. The juglone lists are the Morton Arboretum's, read on 2026-10-05, which warns that "any list regarding this topic is incomplete and some of the information may be anecdotal." The rusts' hosts are the University of Minnesota Extension's, read on 2026-10-06. [What to plant under a big tree](https://bluewhaletrees.com/articles/what-to-plant-under-a-big-tree/index.html.md) and [the article on juglone](https://bluewhaletrees.com/articles/juglone-what-to-plant-under-a-black-walnut/index.html.md) cover the subject.

Sharing a habitat tag does not mean two species always grow side by side, and a tag says nothing about how far apart to plant them. Use the [planting-site check](https://bluewhaletrees.com/tools/site-check/index.html.md) for the spot itself, and the [growth estimator](https://bluewhaletrees.com/tools/growth/index.html.md) for how much room each one will want in twenty years.

The address carries the companion species tool's inputs, so a link opens it filled in, and Copy link on a result writes one: species (a plant's slug, the last part of its page's address, such as white-oak), zone (a whole number from 2 to 10, to keep the companions to it), sort (featured, name, price-asc, price-desc, height, hardy or fast). For example, [/tools/companions/?species=white-oak&zone=6](https://bluewhaletrees.com/tools/companions/index.html.md?species=white-oak&zone=6).