No. Since ostrich fern (Matteuccia struthiopteris) is native to a good portion of the US and Canada (among other locations), it cannot be considered legally/technically "invasive" anywhere in the US. But if well-sited and with good growing conditions, it does have an ability to form large colonies over time.

Thanks.

controlling the colonies over years could be lot of work

Does controlling mean the new growth needs to be dug out ?

Nandina is also invasive forms colonies but Nandina is easy to control by snipping off the new shoots.

Ostrich ferns would definitely not be invassive in the parts of the PNW with dry summers and a little more sun exposure. Ferns struggle with dry summers and native Western Sword fern is a little bit better adapted in that respect. To tolerate dry soil in the summer, they will need shade.

I've sometimes seen Ostrich ferns planted in gardens around here, and never observed evidence of them appearing to spread out of control.

In optimal garden settings, with good soil that stays damp even throughout most of the summer, the ferns can spread agressively. In garden settings they can spread by underground roots and crowd out other nearby plants.

This is good to know. I have added it to the garden at a very shady and very dry location.

Thanks!