My cilantro that over-wintered is going to seed. I’ll collect some seed for use as coriander and some for planting, but much will just drop and self seed later. Now as its flowering it is attracting beneficial insects. Hover flies and lacewings are among the beneficials attracted by the blooms. The only problem with the casual self seeding is that it doesn’t usually germinate until the soil cools in the fall. I most want cilantro for salsa when my tomatoes and peppers are in season. That is the most difficult time to grow it.
Heat causes cilantro to go to seed. Soon I’ll be planting some indoors where it will germinate. When planted just when tomatoes begin to form, I can get some that still has leaves when tomatoes come ripe. I need to keep planting some every two or three weeks to keep leaves available through the summer. Cutting back the seed heads that form can lengthen the time it produces leaves, but only a little. Cutting seed heads on basil is much more effective in keeping it in leaf production. Cilantro is just very determined to go to seed in hot weather.
My parsley is easier. Its a bienniel and after one winter produces the umbel shaped blooms that attract the good insects. This parsley is growing where I planted some about five years ago. It self seeds and I can collect some any time of year. The laissez-faire approach is great for parsley.