Since the plants are next to your door, did anything get spilled on the plant? Maybe a sweetened drink or something?

FataMorgana

Oh man does it ever. I have peppermint, spearmint and even some catnip in a very big pot. Have had it for years. I had to move the pot away from my porch because, when in bloom, the blooms are simply covered in flies.
Only good part is if they are all crowded together on the blooming spikes they stay away from my door? Mint may repel many things, but flues are not one of them.

House flies are absolutely attracted to mint in my garden. No question about it.

I had mint that reseeded itself to a front bed and I let it get out of control and it finally blossomed and I had a gazillion biting flies all over the mint. I was shocked as I thought mint would deter things such as flies. I pulled up all the mint the other day and will continue to until it's all gone. The flies were horrible and again, they were biting me! So not enjoyable!! :-(

i think only peppermint repels flies. I've seen some flies on my other mint species but never on peppermint.

I have peppermint and flies are definitely attracted to the flowers

I have catnip in my back yard and past week I noticed alot of flies around it ..it is in flower mode and they seem to be only hanging out on the flower itself, so I cut the flower buds off to see if they disperse or not...to be continued

I have a big planter box on my porch filled with peppermint and spearmint. They both draw flies when in bloom. I have to allow me to pull cuttings to root and sell for ground-cover. But when in bloom, yes they draw flies like crazy but also various bees - the bumblebees and honey bees love both types. The deal is if you want mint for teas etc, just keeping it cut will produce more tender leaves, and no bugs period. All herbs are like this. But if you want to trap the flies, use anyone of the dozens of traps commercial or DIY right next to it and they will go in and you can reduce a population pretty quick because they are in one place. Now...I use them as ground-cover right along my large shrub beds or around the base of trees— there is nothing nicer smelling and that will make you feel cool than cutting along your beds and cutting the mint too. It stays smelling nice for a good while and the you can just rake it over into the bed to act as mulch or just leave it. It will also help keep weed eaters away from the base of the bush ir tree and prevent girdling. By doing when ever it’s blooming, you eliminate the blooms and no bees or flies. But as I said, most herbs in flower draw all kinds of bugs. It’s the leaves that you want, if you let them bloom that signals the plant to produce seed as all those critters spread the pollen around and the plant thinks it’s year is over and begins to die back. By cutting the blooms off, you get fresh new vigorous growth — plants are always trying to produce seed no matter whether its daisies, orchids, Iris, fruit trees, vines, annuals, perennials - hollies, azaleas, maples, oaks, hydrangea, you name it — the goal of all plants, trees, shrubs, grasses, is to produce seed. Some plants produce seed (or fruit) once a year, others keep trying until winter when they die as annuals or go dormant as perennials to start again next spring. If growing mints ir other herbs, usually, not always, you are looking for the leaves.