From the scientific name it is obvious that giant meadowsweet grows naturally at least in Kamchatka. Also, the common name indicates that it is related to the Finnish native meadowsweet (F. ulmaria). The flowers are indeed similar, but giant meadowsweet is in a completely different class regarding size.
For anyone looking for a large garden perennial, this is a good alternative. The roots grow large, but slowly; a good way to start would be just a few plants with at least half a metre between them. Giant meadowsweet will grow in many situations, but for best results it needs sufficient moisture.
At Mustila, the species grows both in full sun at Juhlapaikka (Festival Area) and in part-shade along the ditch in Alppiruusulaakso (Rhododendron Valley). It is thriving in both places. The handsome foliage takes on yellow autumn colour.