Q.Yellowing leaves on allium
The flowers on my allium are always beautiful, but the leaves are yellowish and unattractive even prior to blossoming. They are planted in full sun.
Allium really don't have many growing issues generally. Proper watering and light fertilizer are generally the biggest requirements.
Did the plants suffer a cold spell after leaves had erupted? Did they have some wet weather or a dry spring?
I suspect something weather related caused some leaf or bulb stress but not enough to hurt the blossoms.
Refresh your Allium care with the links below.
https://www.gardeningknowhow.com/ornamental/bulbs/allium/
https://www.gardeningknowhow.com/ornamental/bulbs/allium/growing-alliums.htm