I believe those may be butterfly caterpillars. Not sure which species, so do not kill them!

I think it is a swallowtail butterfly caterpillar. I think you're lucky to have them!

I think it's a monarch caterpillar. You definitely do not want to kill it.

Save them!

black swallowtail. http://www.pbase.com/rcm1840/lifecycleofblsw

I have been picking the parsley with the caterpillars on them and putting them elsewhere in the yard. I just didn't want them to eat through the whole garden. We do get monarchs here, so many be that's it.

Is 'Elsewhere in the yard' onto a living plant in the Apiaceae? They need to be on the correct food plants if they are to survive.

They are still on the parsley bc I picked little bouquets of what they were on, and let the caterpillars stay on it. I put that in a part of the garden where I don't have our vegetables. Should I make a little habitat like those mesh butterfly tents that are for kids to watch the butterflies emerge? I could make-shift that and put more plants, flowers, fruit, etc. in there for them. I'm no naturalist; just a gardener. We used to have monarchs here 10 yrs ago, then they diminished. If they are trying to come back, I'd like to help them, but not let them eat my whole garden.

I'm afraid that won't help the caterpillars. They need to be on growing plants. They will die on picked parsley. It would be easier to net some parsley for your use than to net the caterpillars. Most caterpillars are very foodplant specific. You can't just give them something else. They won't eat it and will die. The cats are not monarchs. They don't eat parsley. Swallowtails do.

I get so many Swallowtails laying eggs in my garden, I finally devoted a new herb garden to providing food for them. They will eat plants from the carrot family, so parsley, wild parsley, carrot, dill and fennel are usually good food options, and there are others. Dill is very easy to grow, reseeds itself, and at least in may garden it is a favorite food for the caterpillar stage. If you decide to plant some dill for them, realize that it reseeds VERY easily and will spread. It is easy to pull, but if you don't like to weed, be selective where you plant it.

The swallowtail caterpillars on your parsley are voracious feeders and although I think that they and the adults are extremely beautiful, I do not allow them to eat all of my parsley and dill. I simply don't grow that much of it! I crush the eggs and feed the caterpillars to the birds.

As far as monarchs go (change of subject), I decided to stop growing milkweed for them as the plants would be devoured in a very few weeks. The adults frequent my gardens for nectaring purposes but not egg laying.

Most of us don't have the space required to grow dozens or hundreds of sacrificial plants. I don't. My yard provides water, shelter, and pesticide free nectaring opportunities, but I encourage birds and other natural predators, too.

No one should be scolded for wanting to protect their garden edibles!

Hence the suggestion that the parsley could be netted.

ssdarb, you can easily make cages for your herbs with inexpensive tulle, found in a fabric store. Your goal is to keep the butterflies out so they can't lay eggs. Let them have free reign in the rest of the garden.

I've used simple tomato cages as the support for the tulle but have seen nice boxes made of lathe (furring) strips and tulle. Whatever you use, it must be in place as soon as the plant is in the garden.

I bought some milkweed and put it on the other side of the yard. The caterpillars seem very happy there.

Those are black swallowtail caterpillars. They don't eat milkweed. They eat parsley and related plants.

Alright, so do I put them back on the parsley? I could plant a little parsley in a pot I guess.

I put the milkweed and the parsley right next to each, so these caterpillars can choose! Since they were on the parsley originally, I guess they are the swallowtails.

It’s a black Swallowtail catterpiller. Parsley is their host plant, I always grow enough for me and the butterflies.

https://theherbladyblog.wordpress.com

It's a black swallowtail caterpillar. A tiger swallowtail caterpillar is green with eye spots.

It's an Eastern Black Swallowtail and it makes a lovely butterfly.

I was about to upload a picture of the exact same ones! I had them last year and already have them this year. Thanks for beating me to it, and thanks to everyone who answered!

Black swallowtail.If you plant dill and fennel the Swallowtails will probably lay their eggs on them and bipass the parsley.They seem to prefer dill and fennel over parsley and cilantro.There are some attractive milkweeds like Asclepius tuberosa and currasavica with colorful orange,red and yellow flowers that Monarchs will lay eggs on, and milkweed is not good eating for humans anyways.Rue is also a swallowtail host plant,but in the citrus family,not the carrot family.Cutting stems and putting them in water for caterpillars can work,but you have to cut new stems daily and if you forget to, or something important keeps you from doing it the caterpillars will die.

Here is the first of my little guys who is now a butterfly. Fed on cut parsley stems and no, I didn't have to cut fresh stems daily.