What they do
Sourwood offers summer flowers that can help feed visiting pollinators and adds strong seasonal color.
Plant profile
Sourwood
Species Oxydendrum arboreum
Sourwood is a graceful flowering tree known for its summer clusters of white, bell-shaped blooms and rich fall color. It can be a beautiful way to add nectar-rich flowers to a yard or school garden while also providing light shade and seasonal interest.
Plant Type
Trees > Sourwood
Aliases
Sourwood
Native Range
Eastern North America
Bloom window
Summer
OVERVIEW
About This Plant
Sourwood (Oxydendrum arboreum) is a flowering tree valued for its summer bloom and fall color. The flowers appear in long, drooping clusters made up of many small, white, bell-shaped blooms. In a garden, sourwood can act as a seasonal “bridge,” adding fresh flowers later than many spring-blooming trees.
To set sourwood up for success, focus on siting and soil. It generally does best in well-drained soil that leans acidic, with steady moisture while it establishes. A mulch ring helps protect roots and reduces competition from grass, but keep mulch away from the trunk.
In a pollinator-friendly planting, sourwood pairs well with a mix of perennials that bloom before and after it. That way, your garden offers flowers across the growing season, not just for a few weeks.
Best role for pollinators
A feature tree for pollinator-friendly gardens where you can provide acidic, well-drained soil and a little patience while it gets established.FAST FACTS
Quick Details
Essential stats and requirements for quick reference.
| Category | Details |
|---|---|
| Also known as | Sourwood |
| Bloom window | Summer |
| Typical height | Small to medium tree |
| Pollinators supported | Bees, Butterflies, Flies |
| Light & moisture | Sun to part shade; prefers evenly moist, well-drained soil. |
| Best roles for pollinators | A feature tree for pollinator-friendly gardens where you can provide acidic, well-drained soil and a little patience while it gets established. |
SUMMARY
If You Remember Three Things
A quick scan of what they do, what they need, and the best first step.
What they need
A spot with good drainage, slightly acidic soil, and steady moisture while it establishes.
One best action
Choose a well-drained planting site and keep the soil evenly moist during the first growing season.
IMPACT
Why Plant This?
Adding a flowering tree like sourwood can increase the amount of nectar available in your space during summer, while also creating shade and structure that make gardens more inviting.
Sourwood’s flowers hang in long, drooping clusters, giving the tree a soft, lacy look in bloom.
Key Impacts
What it Supports
- Summer-blooming trees can help fill a gap when many spring-flowering trees are finished.
- A flowering tree adds habitat structure and shade, which can make a garden more comfortable for people and wildlife.
- Planting one long-lived tree is a “small step” that keeps giving year after year.
RECOGNITION
Identification Guide
Look for a slender tree with long, drooping flower clusters in summer and bright fall color.
Leaves
Simple, oval to lance-shaped leaves with a clean, glossy look; often turn bright red/orange in fall.
Flowers
Small white, bell-shaped flowers packed along long, drooping clusters in summer.
Fruits
Small, dry capsules that may persist after flowering.
LOCATION
Where It Grows
Native environments and the best spots to place it in your landscape.
Habitats
- Woodland edges
- Upland forests
- Naturalized garden borders
Where it is often used
- Feature tree near a patio or seating area
- Pollinator-friendly schoolyard planting
- Edge of a woodland-style garden
- Small yard tree where a large canopy tree won’t fit
SEASONALITY
When It Blooms
Notes on bloom windows and how this plant helps pollinators across the seasons.
Bloom window
Sourwood typically blooms in summer, offering fresh flowers when many spring bloomers are done.
Bloom Season Role: Mid-to-late season nectar source when fewer trees are in bloom.
Seasonal benefits
- Adds variety to the garden’s bloom calendar
- Provides a reliable floral display that’s easy to notice and enjoy
REQUIREMENTS
What It Needs
The right mix of sun, soil, and space for healthy growth.
Sun exposure
Full sun to part shade. More sun often means stronger flowering, while part shade can help in hot, dry spots.
Soil type
Best in well-drained, acidic soil. Avoid heavy clay that stays wet.
Moisture needs
Water regularly during the first year; after that, water during long dry spells, especially in summer.
Planting method
Plant in a spot with room for the canopy to expand. Keep the root flare at soil level and water in well.
Mulching tips
Mulch in a wide ring to hold moisture and protect roots, but keep mulch pulled back from the trunk.
GARDENING GUIDE
How to Grow It
Simple steps to plant, prune, and maintain healthy trees without pesticides.
Planting tips
- Pick a site with good drainage and room for the tree to grow.
- Dig a hole about as deep as the root ball and wider than the roots.
- Set the tree so the base of the trunk is not buried; backfill gently and water thoroughly.
- Add a mulch ring to reduce weeds and hold moisture, keeping mulch away from the trunk.
- Water consistently through the first growing season.
Seasonal care
- Water during dry spells, especially while the tree is establishing.
- Refresh mulch yearly, keeping it off the trunk.
- Prune lightly to remove dead or rubbing branches; avoid heavy pruning.
- Watch for stress signs (wilting, scorched leaf edges) and adjust watering and site conditions.
What not to do
- Planting in soil that stays wet after rain.
- Skipping watering during the first year.
- Piling mulch against the trunk.
- Using pesticides to handle minor leaf damage.
Pairings
Best Pairings for Season-Long Bloom
Pairing ideas to keep pollinators fed throughout the growing season.
Early Bloom
- Serviceberry (*Amelanchier* spp.)
- Wild columbine (*Aquilegia canadensis*)
Mid-Season Bloom
- Bee balm (*Monarda* spp.)
- Purple coneflower (*Echinacea* spp.)
Late-Season Bloom
- Goldenrods (*Solidago* spp.)
- Asters (*Symphyotrichum* spp.)
If you’re planting in Toronto, check local availability and choose a planting site that matches the tree’s preference for well-drained, acidic soil.
GLOSSARY
Key Terms
A few quick terms you might see when shopping for trees or reading plant tags:
Glossary terms are being added.
What You Can Do
Make a difference for native habitats.
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.