Hi Melissa,

I'm glad you asked these questions. I've been wondering about my flowering parsley and if I should cut it back or not. Didn't know what was best for the cats - leave it or cut it.

Not a dumb question. I'll be watching for the answers, too.

Betty

I cut off the flowers when I see them to encourage more foliage. That way they are not wasting energy on producing seed. My opinion...cut them.

Here is a link that might be useful: My Garden

If you want to pinch the Dill, I would do it when it is fairly small. Dill goes to seed fairly early in the summer, and then peters out in hot weather, so it is not a long-lived host plant.

As for parsley, yes it is biennial and will go to seed the 2nd year, if it survives over the winter. The crown can rot fairly easily during winter if it doesn't have good drainage.

As for the seed heads, I wouldn't cut off them all off. One drawback is that the flowers tend to attract wasps. However, the BSTs seemed to love to lay eggs in the seedheads. I had numerous cats on my one huge curly parsley plant that went to seed last year, of assorted sizes hiding in the seedheads. This was also the first time the BSTs had used parsley as a host plant in my garden.

Also, if you let it go to seed, it will reseed for you or you can collect seed.

In my garden, I grow three plants of the Apiaceae family for the Black Swallowtails. The order of bloom is Dill, Fennel and then Parsley. That is also the order in which the Black Swallowtail lays her eggs...Dill, Fennel, and then Parsley. The caterpillars are always eating from the flowers downward.
This seems to me, to be an indication that it might be a mistake to prune off the bloom heads on these plants. Of these three plants, parsley is the only one that has any substantial leaves and the caterpillars on my plants are found lower on the plant than on the others.

When I observe the plants that have hosted caterpillars for several days, it is always the blooms that have been depleted most. Note the placement of these caterpillars on this Dill plant.

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And this one of a Monarch caterpillar on the Common Milkweed.
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Bob

Beautiful pictures, Bob!
Many cats do indeed prefer the flowers over the leaves - sulphurs are also flower lovers.
Sherry

Thanks for the info everyone and the beautiful pics, Bob. I'm glad to know the flowers can stay without depleting the plant till the point of it's death. I also had no idea the bst cats would even be remotely intersted in the flowers. I love learning new things!!!