Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Rosales
Family: Rosaceae
Genus: Spiraea
Species: S. douglasii
Binomial name: Spiraea douglasii
Common name: Steeple bush, Douglas Spirea, Pink Spirea, Rose Spirea, Western Spiraea, Steeplebush, Hardhack.

Spiraea douglasii is a species of a vigorous suckering flowering plant native to western North America from Alaska where it occurs most often in riparian habitat types, such as swamps, stream banks. This invasive woolly shrub grows to 1.5 m tall from rhizomes and can form dense thickets.
In summer tiny pink to deep rose numerous flowers (5 mm across) form in narrow, pyramid-shaped clusters up to 20 cm long. These clusters darken later in the season. The tiny seeds are to be thought to be dispersed by wind.
The dark green leaves are oblong to oval, 2.5 cm to 10 cm long with smooth edges near the base and toothed above the middle. The leaves undersides are a lighter colour with prominent veins.
Spiraea douglasii was introduced to New Zealand as a garden plant and is found in abandoned areas such as the Denniston Plateau.

Spiraea douglasii Steeple bush.JPG

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The top surface of a leaf.
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The underside of a leaf.
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Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/