You can plant under a fruit tree, but be aware that in many cases it will compete with the tree for nutrients. I've thought about companion planting herbs to try and deter aphids and other pests, but haven't really gone through with it.

https://youtu.be/6STuSTlfnsE

How about some daffodils? I've actually heard of someone trying chicory also but I don't know the results of either experiment. Under trellis cover crops definitely need more research.

They've done some research, and found that it does compete with the plants. That can be useful if you are trying to control vigor, but may reduce total yield.

Thanks for your comments,

I like the daffodils, I reckon if you plant rhem deeply, propperly, weeding wont harm them, and they can get really old around here

Apart from that I will then stick to mulching and keep few Ladys mantle on the strip between the kiwi plants.

it was an odd year, late frost killed all new foliage, they resprouted, and now, after a long dry spell, 2 looked quite bad (hadn't watered their spot properly), the third had dipped into water for near by roses (I guess), and managed to send out a new, really long shoot, yei!