Fennel, dill, aneth, fenouil... it's a little confusing. I've never tried growing vegetable/bulb fennel, I don't care for it all that much, even veggie lover as I am. The herb one we have is the bronze one, and I think, like the bulb, it's called fenouil in French. I've always tended to think it very similar to all intents and purposes to dill herb, which is called aneth here. But then I asked Polish Chick, I think it was, or maybe Joe, who was also devotee of dill if not a fan of fennel, whether I couldn't substitute fennel for dill in a recipe - it might have been gravlax or pickles - as I didn't have any of the latter, and I received an uncompromising no, dill was distinctly different in flavour from fennel! (None of this alliteration took place at the time, whomever the conversation was with.)
So I tried growing some dill, and the germination was rubbish but then some of the seeds did come up eventually, and I've carefully nurtured the plants, but now they've grown big I can't honestly smell, taste or even see, once the dill plants grew beyond the early feathery-leafed stage, much difference between the two, and I haven't got around to making either gravlax or pickles with them.
However, they are both attractive to a somewhat unusual range of insects. Greenbottle type flies, which aren't very pleasant really but I suppose they have their place in the scheme, and also these curious leggy wasps:
They are the most unassuming and gentle creatures, showing no inclination to sting or bother one at all; in fact looking at the photo perhaps they don't even have a sting or aren't even true wasps. I'll try to find out.
[Edit: they appear to be paper wasps, polistes dominula. Some dizzyingly detailed facts about them in this Wiki link; how do people know all this stuff?]
The other insects which are drawn to it, not to feed but to breed, are the swallowtails. Not always, some years we see them often, others not at all, when they simply flutter through they are so rapidly moving and elusive I can seldom photograph them, but on this occasion one set about laying its eggs, or attempting to, on the plants, and being thus preoccupied, I was able to capture it on camera, with a lot of zoom.
I've since looked for the eggs or caterpillars, but no sign. Other years we've had them on various other plants, mostly other umbelliferous ones like carrots or parsley, but also on some Mexican orange bushes where this butterfly was also prospecting, and I have even been known to take them off and overwinter them as chrysalids in a terrarium, with a small amount of success. Both as caterpillars and as butterflies, they are impressive creatures, I think, at least by the standards of this corner of northern Europe.