Spirea vs Ninebark: Shrub Size Plus Color Plus Pruning
Spirea vs ninebark mostly comes down to size, leaf color and bark. NC State Extension says spireas grow 2 to 10 feet tall depending on the species. Ninebark is a native rose family shrub known for bark that peels in layers.
The short answer
Choose spirea for a compact shrub with heavy bloom. Choose ninebark for leaf color and peeling bark. Clemson Cooperative Extension says most spireas grow 1.5 to 8 feet tall. NC State Extension lists ninebark at about 5 feet tall and 4 feet wide. Prune spring bloomers of both right after flowering.
How do size and form differ?
Spirea sizes differ widely. Clemson Cooperative Extension says they range from 1.5 to 8 feet tall. Vanhoutte spirea arches 5 to 8 feet high and up to 10 feet wide.
NC State Extension lists common ninebark at about 5 feet tall and 4 feet wide. It is a deciduous, flowering shrub native to central and eastern North America.
Smaller ninebark forms exist. NC State lists Lemon Candy at 2 to 2.5 feet tall and 2 to 3 feet wide.
Which offers more leaf color?
Ninebark. NC State Extension lists many purple leafed cultivars such as Diablo, whose leaves open a deep purple. Others such as Aurea have gold or chartreuse leaves.
The same source says purple leafed types can lose intensity when exposed to sun for long periods each day.
Clemson says most spireas are deciduous and some have colorful fall foliage. Ninebark also offers bark that peels in strips to show reddish to light brown layers in winter.
| Trait | Spirea | Ninebark |
|---|---|---|
| Height | 1.5 to 8 feet, by species | About 5 feet |
| Leaves | Mostly green, some fall color | Green, purple or gold forms |
| Bark | Brown plus smooth | Peels in layers |
| Origin | Many species, some invasive | Central plus eastern North America |
Source: Clemson Cooperative Extension plus NC State Extension.
How is each pruned?
NC State Extension says spireas that bloom on old wood should be pruned after flowering. Those that bloom on new wood can be pruned in fall or at any time.
Clemson says to prune summer blooming bumalda spireas in winter or early spring. Removing faded flowers on any spirea spurs a second flush of growth plus more flowers.
Ninebark blooms on old growth. NC State says to prune right after blooming, but no later than mid August.
How to: step by step
- Measure the space for mature width.
- Pick spirea for bloom or ninebark for leaves.
- Plant in full sun for the most flowers.
- Prune spring bloomers right after flowering.
- Prune summer spireas in winter or early spring.
- Stop pruning ninebark by mid August.
Troubleshooting
Few flowers: too much shade. Move to full sun.
Faded purple leaves: long sun exposure. Expect some color loss.
Lost blooms: pruning at the wrong time. Prune after flowering.
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Sources
- Spiraea (spirea), NC State Extension Gardener Plant Toolbox
- Spirea, Clemson Cooperative Extension HGIC
- Physocarpus opulifolius (ninebark), NC State Extension Gardener Plant Toolbox
- When should I prune spring flowering deciduous shrubs?, Iowa State University Extension, Yard plus Garden
FAQ
Is ninebark native to North America?
Yes. NC State Extension says ninebark is a flowering, deciduous shrub in the rose family native to central and eastern North America. It does well in slightly acidic, dry to medium, well drained soil in full sun to part shade. It tolerates heat, drought and soil compaction.
Do spireas bloom more than once?
Some rebloom with help. Clemson Cooperative Extension says that once flowers on any spirea cultivar fade, removing them stimulates a second flush of growth with more flowers. Some spireas bloom in spring and others in summer. Clemson says they produce more blooms and grow denser in full sun.
Which shrub is deer resistant?
Clemson Cooperative Extension says spireas are generally deer resistant. The ninebark source does not rate deer resistance, so plan on spirea where browsing is common. Clemson also notes that Japanese spirea is considered invasive in the Southeast US and is not recommended there.
How large does ninebark grow?
NC State Extension lists common ninebark at about 5 feet tall and 4 feet wide. Cultivars vary. Lemon Candy reaches only 2 to 2.5 feet tall and 2 to 3 feet wide, while Snowfall is a dense green form near 7 feet. Pick a cultivar to fit the space.
When should overgrown shrubs be cut back?
Iowa State University Extension says the right time to rejuvenate large, overgrown spring flowering shrubs is late winter or early spring. Heavy pruning then will reduce or eliminate flowers for 2 or 3 years. Well maintained shrubs need only light pruning right after flowering.
