These are not something you want to encourage to grow in your garden. Once you have them, you will have them forever. The little black seeds have a very high germination rate and as an invasive species, it is an offence to deliberately plant it in the wild in the UK.
Having said that, I was grateful for them recently when green vegetable supplies were running low. Unlike the ones seen when out foraging, the ones in my garden are in free-draining soil in a raised bed and receive plenty of water so they were especially plump, including the bulb which is also edible. See other pic attached for comparison. Usually, they have to compete with other plants, often other three-cornered leeks, since where they occur, they usually occur in abundance. The ones left in my garden are destined for the pot before they flower and shed seed, but I know there will be more next year.
The only safe way to grow them might be in a pot surrounded by concrete where there was no chance of the seeds germinating. Otherwise, take the leaves, wash, and use as required. They can be identified by the smell. See advice online to help.