The two that I see most often here are the tiger and colossal. I think the reason they like the fennel and coriander is that the birds feel the same as I do about the taste especially concentrated.

@glennlab One that is common here is the bronze Fennel.

I don't particularly like the the licorice flavor, so it is just for the butterflies, it is both a host and nectar source for the swallowtails.

@glennlab I wish mine would attract the swallow tails, we can I think just get them in the UK, but I am fairly well north.

@glennlab It seems that our swallow tail here, lives on the Milk Parsley, Peucedanum palustre , so perhaps I would not get it on fennel anyway.

You say that you do not like the licorice flavour, does that mean that you are growing the Florence Fennel type with the edible white bulbs at the base ? Have you tried the leaf herb, which has more of an anice flavour.

@Fernapple Since I'm not a fan of the flavor, I buy my seeds at the asian market, I get about 70 % to sprout and only pay $3 a pound instead of $3 for 1/8 of an ounce. I buy my cilantro the same way for a simalar price difference. I don't eat it either, but the swallowtails like it too. You really have to check on what the local butterflies like. I have adjusted my plantings so that I have a good mix for several varieties.

@glennlab . The local Amish Bulk Food Store sells most seeds as baking and cooking supplies in bulk for about 2% of the cost of seed packets. Alfalfa sprouts anyone?