Fatalistic Fennel?

My daughter wanted fennel seeds, so last year I planted fennel in a couple of my raised beds. I looked up how to grow it, companion plants and planted it. The tomato, squash, zinnia and cosmos germinated and grew very well. This year I have a tomato growing in that raised bed, and it seems to be growing as well as the other tomatoes in different beds.
I keep seeing fennel keeps other plants from growing, and even continues after the fennel has been removed. So far this is not my experience, but I keep seeing it and I'm a little worried.
Have you grown fennel? Did it have a negative affect on the surrounding plants, or soil?

I have Fennel planted in some of my orchard areas, but not in my vegetable garden.
I haven't noticed it preventing the growth of other plants in the orchard, except for taking up a lot of room and crowding out other plants when it gets big.  I have only just now read about its supposed allelopathic affect on certain types of vegetables.  The reason I don't have it in my garden is because it makes lots of seeds and volunteer plants come up readily making it weedy in my climate.
 

It grows wild here.

I've never noticed that it causes problems other than attempting to shade stuff out, but so far it hasn't invaded the veggie beds.

It's attempting to out-compete the prickly pears and the peruvian apple cactus though!