Here’s some insights into why your Russian Snowdrops may have lost their colour and how you can help them:

Environmental Factors:
Sunlight, soil conditions, and temperature can all affect the intensity of the blue stripe.

Plant Maturity:
The vibrancy of the flowers may decrease as the bulbs mature.

Overcrowding:
Overcrowded bulbs may lack the necessary resources to produce intense colour.

Ensure Proper Care:
Plant the bulbs in well-drained soil and ensure they receive adequate sunlight or partial shade.

Don’t Overcrowd:
Space the bulbs adequately to allow for proper growth.

Consider a New Location:
If the current location isn’t ideal, move the bulbs to a spot with better conditions.

Be Patient:
Allow the plants time to establish themselves and mature, as the blue stripes may return in future years.

Bulb Health:
Ensure the bulbs are healthy and free from diseases or pests.

After Bloom Care:
Allow the foliage to die back naturally after the flowers fade to provide nutrients for the bulbs for the next year’s bloom.

I hope this helps you understand and address the fading blue stripes in your flowers. If you have any further questions or need additional assistance, please don’t hesitate to ask.