It has happily grown between two fair sized clumps of Tetrapanax until this spring. Conditions this spring clearly favored both clumps because they erupted with new growth and are engulfing the elderberry.
Here are a few combinations that don't behave as aggressively... not that the violets aren't going to need serious thinning by early fall.
This clump of 'Ghost' Fern grows right in front of a much larger clump of Autumn fern.

Japanese Painted Fern grows less than two feet from a cluster of 'Muscadet' Oriental Lilies
[yes, the photo is a composite]

Small 'Mini-Skirt' Hostas grow next to an equally small Tokyo Wood Fern

A Corsican Hellebore [Helleborus argutifolius] grows next to a fair sized 'Brother Stefan' Hosta