Yes, deadheading can impact flavor. Once the flowering cycle begins, the plant isn't putting it's best into the leaves, and they can get big ole bitter. Like how some lettuce can get from good to bitter between young leaves and older bolting time leaves. Pinching back flower buds can help promote fresh growth that is tastier than the older growth. With basil in particular, pinch back to the node under the flowering node- it will promote fresh growth and branching. But by this time of year the drive to produce flowers and seed drives the basil so hard, they kind of start to go ptttht regardless of pinching. Then I start a pot for indoors. I do my parsley in bins and grow curly in one and flat in another. Since they are biannuals I let them roll. In the spring I'm harvesting last years plants still, but once last years seed grows big enough I'm harvesting off that and letting last years plants go to flower and seed. In the fall I crumble off the seed heads right into their bins. Since I cap my bins, I have some fresh parsley through the winter, though not much. Thyme, oregano, sage, and mint I don't bother deadheading because I have so much of it growing and the bugs love them. And they are all perennials here, so I want them to stay put. I got savory and marjoram in there somewhere too, some lemongrass, catnip that I let keep sowing itself... I keep a small stand of bronze fennel for the bugs- it can seed and weedy forever, but I think it's worth it. Last years bulb fennel I left to go to seed to start creating a perpetutal bed with that since it too self sows so easily.

nicole___ Here are some shots of the rhododendrons. The gardebs are on the messy side — I need to do some trimming of some areas where I have deadwood and errant pest vines. All in all the abundant rainfall we had in April and May gave us some lovely blooms. Doublefile viburnum in foreground needs to be tidied up. House wrens use the old nest box. I like them and they seem to eat a lot of insects. ”Lawn” is filled with Prunella vulgaris (self heal) and moss. Rhododendron ’America’ Beauty Bush (where the catbirds nest every year. I wanted to thin this area out, but we had many rainy days. Then the shrubs leafed out, the the catbirds arrived. Bees, swallowtail butterflies and hummingbirds enjoy the beauty bush which readily self sows. This white rhodi always gets WHITEFLY 👿 and severely. I am not sure what to do, but these rhododendrons are very close together on a north-facing slope. Perhaps I should try to improve the airflow and circulation by pruning and thinning. If I can stand to lean over for a few minutes, I could easily root, air layer propagate the Nova Zembla (red rhodi). I put the three paper birches there when they were saplings.

Shouldn't they just shrivel up rather than produce seeds? I haven't seen them produce seeds before. I should have mentioned it is potted, so not as capable of taking care of itself as something established in the ground. It does live on the open balcony all year round.

That's possible, but deadheading Crocosmia won't produce more flowers in the current year, which is what I believe the OP is asking about. Anyway Crocosmia doesn't need any encouragement so I wouldn't bother deadheading. Quite apart from it's being fiddly and time consuming. For the catmint shearing the whole plant is fast and effective. It doesn't need deadheading as such.