For years I keep tossing cilantro because it goes bad.
It's really cheap here but I don't want to run off to the store to buy cilantro to cook with all the time.
Should I parboil it and chop it up first before freezing?
What's the best method?

I'm lazy. I just cut the whole plant(s) put it (them) in a white plastic trash bag in the freezer until they are frozen solid. Then squeeze and mush the bag to break up the leaves, remove the larger pieces of stem and repackage remaining leaves into smaller baggies to freeze. Work fast, so they don't have a chance to warm up and get soggy.

Some people chop fresh and freeze into ice cube trays with a bit of water. Pop out and save cubes in a big ziplock. No parboiling needed.

Think the ice cube method sounds good. Will have to try that. Dried is tasteless and haven’t tried freezing in a bag. Kind of give up on cilantro after the spring and switch to Vietnamese Coriander. Cuttings root fast in water so I now have a steady supply to plant in the garden and pots. Pot it up for the winter indoors and then plant out when danger of frost is over.

@Gardadore
The stuff is like 38¢ a bunch here where I live.
So you say if I took some cut from the store I could root it?

Cilantro, parsley, and culantro won't grow from rooted stems, though I've tried it. They actually root, but just sit there, and and don't spread. Years ago, when cilantro wasn't widely available here, I wanted to find some way of saving them, but frozen isn't as good as fresh - it's good in hot dishes, added at the end, but in fresh, and not chopped real fine, the fresh is much better.

Regular cilantro doesn’t root but Vietnamese Coriander has thicker more woody like stems and does root. The leaf is different but I love the cilantro flavor of it. It thrives in the summer heat compared to regular cilantro. It’s my go to replacement. Hard to find the plants which is why I have resorted to cuttings. I leave the pot of planted cuttings on my kitchen windowsill all winter so I am ready to go in the spring.

I haven't tried freezing but otherwise no luck trying to preserve the leaf and its flavor.

However I have to say again that green cilantro seeds are an underappreciated spice. If you have cilantro in your garden and it bolts, try cooking with the green seeds, or you can even cut and dry the green seeds to use as a spice with fresh leaf flavor.
I do a lot of bulk cooking and freezing and I can confirm that green coriander seed will stay flavorful in your dish, in a way that leaf no chance. Tastes like the fresh leaf but maybe a little more pungent and strong. I'm just sitting down to a curry made with fresh green seed from the garden and frozen... the cilantro taste is excellent.

Bower, we will have to try that as we love the taste of cilantro, but the heat makes it bolt so fast or just burns up.

Will also have to find some seeds for the Vietnamese cilantro to try.

I just chop and freeze it in a bag. It doesn't lose its colour, not sure about the taste because I only use it at the end of cooking curries.