# 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=texas-red-oak

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.

## Texas Red Oak grows in rocky ground, dry uplands and stream banks

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

- [Little Walnut](https://bluewhaletrees.com/plants/little-walnut/index.html.md) (*Juglans microcarpa*): Small tree, 20–30 ft
- [Ouachita Indigobush](https://bluewhaletrees.com/plants/ouachita-indigobush/index.html.md) (*Amorpha ouachitensis*): Shrub, 3–6 ft
- [Cedar Elm](https://bluewhaletrees.com/plants/cedar-elm/index.html.md) (*Ulmus crassifolia*): Large tree, 50–70 ft
- [Gum Bumelia](https://bluewhaletrees.com/plants/gum-bumelia/index.html.md) (*Sideroxylon lanuginosum*): Small tree, 15–45 ft
- [Rusty Blackhaw](https://bluewhaletrees.com/plants/rusty-blackhaw/index.html.md) (*Viburnum rufidulum*): Small tree, 10–20 ft
- [Lanceleaf Buckthorn](https://bluewhaletrees.com/plants/lanceleaf-buckthorn/index.html.md) (*Rhamnus lanceolata*): Shrub, 3–15 ft
- [Dwarf Hackberry](https://bluewhaletrees.com/plants/dwarf-hackberry/index.html.md) (*Celtis tenuifolia*): Small tree, 15–30 ft
- [Upland Swamp Privet](https://bluewhaletrees.com/plants/upland-swamp-privet/index.html.md) (*Forestiera ligustrina*): Shrub, 6–10 ft

## Under its canopy

Shrubs that take the shade a Texas red oak casts and like the same soil.

- [Gray Dogwood](https://bluewhaletrees.com/plants/gray-dogwood/index.html.md) (*Cornus racemosa*): Shrub, Zones 4–8, 4–10 ft, Price on request. Shares rocky ground, dry uplands and stream banks in the wild. Hardy in zones 5 to 8 of the Texas red oak's 5 to 10.
- [Carolina Buckthorn](https://bluewhaletrees.com/plants/carolina-buckthorn/index.html.md) (*Frangula caroliniana*): Shrub, Zones 5–9, 10–20 ft, Price on request. Shares rocky ground and dry uplands in the wild. Hardy in zones 5 to 9 of the Texas red oak's 5 to 10.
- [Roughleaf Dogwood](https://bluewhaletrees.com/plants/roughleaf-dogwood/index.html.md) (*Cornus drummondii*): Shrub, Zones 5–8, 6–15 ft, Price on request. Shares rocky ground, dry uplands and stream banks in the wild. Hardy in zones 5 to 8 of the Texas red oak's 5 to 10.
- [Downy Arrowwood](https://bluewhaletrees.com/plants/downy-arrowwood/index.html.md) (*Viburnum rafinesqueanum*): Shrub, Zones 3–8, 3–10 ft, Price on request. Shares rocky ground and dry uplands in the wild. Hardy in zones 5 to 8 of the Texas red oak's 5 to 10.
- [Mapleleaf Viburnum](https://bluewhaletrees.com/plants/mapleleaf-viburnum/index.html.md) (*Viburnum acerifolium*): Shrub, Zones 3–8, 3–6 ft, Price on request. Shares rocky ground and dry uplands in the wild. Hardy in zones 5 to 8 of the Texas red oak's 5 to 10.
- [Deerberry](https://bluewhaletrees.com/plants/deerberry/index.html.md) (*Vaccinium stamineum*): Shrub, Zones 5–9, 5–15 ft, Price on request. Shares rocky ground and dry uplands in the wild. Hardy in zones 5 to 9 of the Texas red oak's 5 to 10.

## Beside it

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

- [Winged Elm](https://bluewhaletrees.com/plants/winged-elm/index.html.md) (*Ulmus alata*): Medium tree, Zones 6–9, 40–60 ft, Price on request. Shares rocky ground, dry uplands and stream banks in the wild. Hardy in zones 6 to 9 of the Texas red oak's 5 to 10.
- [Black Hickory](https://bluewhaletrees.com/plants/black-hickory/index.html.md) (*Carya texana*): Medium tree, Zones 5–9, 30–80 ft, Price on request. Shares rocky ground and dry uplands in the wild. Hardy in zones 5 to 9 of the Texas red oak's 5 to 10.
- [Laurel Oak](https://bluewhaletrees.com/plants/laurel-oak/index.html.md) (*Quercus hemisphaerica*): Medium tree, Zones 6–10, 40–60 ft, Price on request. Shares dry uplands and stream banks in the wild. Hardy in zones 6 to 10 of the Texas red oak's 5 to 10.
- [Hop Hornbeam](https://bluewhaletrees.com/plants/hop-hornbeam/index.html.md) (*Ostrya virginiana*): Medium tree, Zones 3–9, 25–40 ft, Price on request. Shares rocky ground and dry uplands in the wild. Hardy in zones 5 to 9 of the Texas red oak's 5 to 10.
- [Post Oak](https://bluewhaletrees.com/plants/post-oak/index.html.md) (*Quercus stellata*): Medium tree, Zones 5–9, 35–50 ft, Price on request. Shares rocky ground and dry uplands in the wild. Hardy in zones 5 to 9 of the Texas red oak's 5 to 10.
- [Eastern Red Cedar](https://bluewhaletrees.com/plants/eastern-red-cedar/index.html.md) (*Juniperus virginiana*): Medium tree, Zones 2–9, 30–50 ft, Price on request. Shares rocky ground and dry uplands in the wild. Hardy in zones 5 to 9 of the Texas red oak's 5 to 10.
- [When these flower and fruit](https://bluewhaletrees.com/tools/calendar/#plants=texas-red-oak,gray-dogwood,carolina-buckthorn,roughleaf-dogwood,downy-arrowwood,mapleleaf-viburnum,deerberry,winged-elm,black-hickory,laurel-oak,hop-hornbeam,post-oak,eastern-red-cedar), in the bloom and fruit calendar.
- [What to plant under a big tree](https://bluewhaletrees.com/articles/what-to-plant-under-a-big-tree/index.html.md), and how to plant without harming its roots.
- [The habitat around a tree is part of the tree](https://bluewhaletrees.com/articles/habitat-around-a-tree/index.html.md): what keeps its roots alive.
- For the shade under an oak, the [Shade Understory Pack](https://bluewhaletrees.com/bundles/shade-understory/index.html.md) sells five as a set.

## Email me when Texas Red Oak or a companion is ready to order

For Texas Red Oak, Gray Dogwood, Carolina Buckthorn, Roughleaf Dogwood, Downy Arrowwood, Mapleleaf Viburnum, Deerberry, Winged Elm, Black Hickory, Laurel Oak, Hop Hornbeam, Post Oak: one email per plant when it is priced or back in stock, and nothing else.

## 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.
- **Your zone.** With a zone chosen, the yard lists keep only species rated hardy in it.
- **Black walnut.** The 37 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 25 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 we do not grow.** The note under the menu names a relative we grow, in the words of its page.

The communities are our own tags. The states of native range are the USDA PLANTS Database's records, read on 2026-09-23, 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. 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 plants 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.