Question on bulbs in the garden????

I have plenty of bulbs in my garden....some of them seem to be getting shorter and smaller every year. They are not crowded and they have not multiplied (I wish they would)... (quả óc chó giá rẻ)
I have tried dividing my trumpet lily that someone had recommended because they get full heads on them but they are only a fourth of what they were in height. They came up as shorter again and when I dug them up to replant them, they were not crowded.
I was hoping that was the problem.....should I be replacing the bulbs with new ones? I am not sure if bulbs loose their energy even with bulb food, etc. I also thought the chipmunks/mice might be munching on parts of them but the ones I have checked are OK..

 

Hi @tonytrong, a little info would be appreciated, where are you, and soil type, do you live in a hot dry country, ref chipmunks, we may be able to offer a little more help then.

 

Hi Tony,
Welcome to Gardeners Corner

Do you know the name of your Lilies ?

Also, how many times have you dug them out/replanted ?
It could be that they are not settled and are using all their energy into building up their bulb size.

Also some Lilies root from the stems as well as the bulbs so they have to be planted quite deep.