Hello Fleur,
The name "Garlic Chives" is too entrenched in social media over the years to be able to correct the mis-association to incorrect plants. So due to the propensity of misnaming, I can accept the common name of "Garlic Chives" towards it meaning Allium tuberosum (yet having no connection to "garlic" nor "chives)… going back to my belief common names are essentially useless. Allium tuberosum can flower and have maturing seed capsules at the same time, it's so quick to dispense seed. It's a pretty plant in flower, but oh so aggressively seeding. If one wants an awesome autumn-blooming Allium (of which there are many), select the Japanese Allium thunbergii (often sold in the selected short form Allium thunbergii 'Ozawa') which has deep rose-purple blooms in autumn
