Using plant roots to help secure rock retaining wall

I feel like I've seen this before but can't find it.  Please redirect me if I should post this elsewhere.

I've redone some retaining walls with available boulders and would like to plant something with long roots to hold it all together.  I've got plenty of comfrey already and for this location want something a bit shorter.  Bonus if it fruits.  Can anyone thing of something with long roots that would hold things together?  It would need to survive zone 3.  thanks

This article has some suggested plants
:

Selecting drought-tolerant plants for retaining walls reduces upkeep while adding texture and color to your landscape. Hardy species such as sedum, thyme, and juniperus horizontalis thrive in rocky, well-drained soils, making them ideal for retaining wall gardens. Their deep root systems help prevent erosion, ensuring long-term stability for your wall

https://jcbdesignscapes.com/choosing-the-right-plants-for-your-retaining-wall-garden/

Anne Miller wrote:This article has some suggested plants
...

Thanks!

In the past, I've considered using bellflower, but it has a fearsome reputation and I have limited land.