Allium 'lavender bubbles', flower stems withering

Hello, another query from me.

Edit: turns out it's slugs eating the outer layer of the stems!

I have lovely Alium 'lavender bubbles'. Planted last year, 6 pots. They're in a sunny location at the front of the house. Gravel much. Everything was watered through that first summer and the intention was to leave this as a drought tolerant garden. It's rained a lot though!
The Alium was the first thing to get going again in spring. Now the flowering stalks are coming up, some are just withering. They're turning yellow.
I wondered if it was in need of water but I'm concerned it might be something else. Is there anything that can cause this issue?

Any ideas or help welcome!

 

Hi

Its been so wet, that causes the yellowing of the leaves .. but as you can see from your photo the new growth is looking very green and fresh ... just trim the old yellow leaves off ... they may need a feed as well ... yet again all this rain past 10 months lol yes 10 months has washed out all the nutrients in the soil

Spruce

 

I've figured out the problem!! Little slugs are eating the outer layer of the stems!