There are two types found here - one is native, the other an introduced species.
MEADOWSWEET : Filipendula ulmaria
This is our native species.
As the Woodland Trust puts it Sweet by name, sweet by nature. Meadowsweet might not be to everyone’s taste, but you’re unlikely to mistake the sickly sweet and frothy flower in damp woodland and bubbling out of damp ditches.
Yet many of us do miss it. We get very familiar with plants such as cow parsley in profusion over the spring that when this one appears i mid-June it simply looks like an unruly version of that. But look closer and you will see very pretty cream profusions of flowers on tall stalks. It thrives where the water level varies as here alongside the upper Leven.
It attracts many insects and can be useful to us too. Meadowsweet has painkilling properties thanks to compounds similar to aspirin. It was steeped in water as a relieving tea before medicines for pain were widespread. It’s also edible and can be used as flavouring in a similar way to elderflower. It was once valued for its lasting fragrance; the dried flowers were strewn across floors to perfume the home. It was also used in Anglo-Saxon times to flavour mead.
It can be difficult sometimes to tell which leaves belong to which plant (confusing in the pictures above), but here are the stalks and leaves more clearly.
A closeup of the flower clusters.
WHITE MEADOWSWEET : Spiraea alba
In spite of the "alba" in its notanic name, this is the introduced species and is commonly known as meadowsweet, white meadowsweet, narrowleaf meadowsweet, pale bridewort, or pipestem, is native to the wet soils of the Allegheny Mountains and other portions of eastern North America. Yet another escapee from someone's garden growing on the upper Leven towpath.
And in spite of the "white" in its English name, one of our examples is a pink variety. But if watched over time you will see them fade to almost white.
The native species is rather frothy. This one at a glance looks very different. But look closely at the flowers of each one and you will recognise the similarity.
Narrowleaf meadowsweet shrubs often reach 8 feet in height with a spread of 3–4 feet. This species is often the most conspicuous part of the vegetation in its habitat, taking up large areas of ground. Its leaves are glossy yellow-green, oblong or lance-shaped, and toothed on the edges, and its twigs are tough and yellowish brown. Fall foliage is golden yellow. The white and sometimes pink fragrant flowers grow in spike-like clusters at the ends of the branches, blooming from early summer through September. The brown fruit, which persists after flowering, is a distinctive feature of all Spiraea species. [Wiki].