I can think of 2 big reasons bulbs come up 'blind'. Maybe 3.

1) Insufficient sunlight: they need at least 5 hours of full on sun per day to bloom.

2) Cutting the green leaves last year: if you cut the green leaves on last year's blooms, they may have not had sufficient energy stored up for this year's blooms. When the blooms fade, leave the green leaves to photosynthesize until they turn brown and flop over. Then you can cut the leaves. Cutting them too soon may sacrifice the following year's flowers.

3) Pathogens or pests (squirrels).

Sorry but the big Alliums leaves disappear, or have begun to die before the flowers appear. However, if the plants are still growing and not flowering rather than not coming up at all, then lack of food is as likely as anything. As soon as the leaves appear then start foliar feeding every 10 days or so. Producing a flower is a big effort for a plant so you need to feed them.

which alliums? if they are the large types like cristophii or purple sensation then as Owd says their leaves fade before they flower. [its often a 'problem' when selling them as the leaves look awful just as the buds start to appear]. A good foliar feed or enrich the soil around them will also help for next year. They may in fact flower for you this year as we had a good hot dry summer. Ideally they like to be in sun for a good part of the day.

She doesn't specify type, but the alliums I see all have large flat ribbon-like leaves while in bloom, even when I googled it. I found the leaves very attractive. A photo would be very helpful.

In really cold climates, such as yours, Bathgate--hope you took the latest blizzards with little harm!--the big Alliums often keep their foliage until bloom, while in more moderate climates, such as most of the UK, the leaves die back for the summer shortly before the flower spikes rise. Foliage growth is determined by temperature, while bloom is triggered more by day length, as well as temperature. The causes of blind bulbs have all pretty much been listed, though planting too shallowly or deeply can easily have that effect, too. Eventuall, the bulbs work their way to the proper depth, but that can take years.

Thanks for clarifying Tugbrethil. The blizzard never made it here because of the maritime effect. Everything was blown north towards Massachusetts. We haven't had much snow at all this year and the little kid in me feels cheated. lol!

I'm really glad you asked that question Kate because I have failed miserably when trying to grow alliums. Mine were all in a very sunny position but maybe I didn't plant them deeply enough. Lets try again.

Hi everyone, thank you for all the feedback and advice. Sorry I do not have any current photographs to share!
The allium variety was christophii, the larger bloom heads. The leaves were long and thin, leaves become crispy and brown when blooms fading.
Also, they were positioned in an afternoon sunny spot. Maybe not enough sun as someone advised?
Also, I do admit to perhaps. Turing the leaves off when brown and crispy.
I actually think I may have a photo! One of the very few that actually bloomed! I shall have a look. Think 30 bulbs planted and only a few actually flowered.

Thank you Ginellie, I don’t feel so alone now! I agree, let’s try again! :)

Kate, I think that we have all been assuming that these bulbs did flower the first year you had them, and then haven't bloomed in subsequent years. Are you actually saying that they didn't bloom the first spring? If so, that brings up a whole other list of causes.

Morning Tugbrethil, thank you for your message. Apologies, I should explain. Around 30 or more planted, but for the past three years only a few have bloomed ( from initial onset) same ones by the looks of positioning. Othes sporadically come up blind with just some leaves and the majority since planting has never ever even produced shoots or leaves.
The ones which never appear to bloom are in the back and from garden. The back garden close to the house where bulbs are planted has early morning sun through to a mid afternoon. The front smaller garden, which have bulbs planted in a gravel/cobble area, has mid afternoon sun to sunset. Hope this helps?
Many thanks, Kate.