Colours are special, especially spiritual colours. When you see colours that spirit is showing you, they all seem so much more intense and so much more colourful.
All mediums prefer to use their own meanings for each colour. Sometimes they use the meanings for the colours in the aura, red, orange, yellow, green, blue, indigo and violet.
What I did when I first began working with colour, was to look at each one and see what I felt. I seemed to get a special feeling with each colour and it seemed to mean something to me. I began with just the 7 colours of the aura as I felt that was enough whilst I was learning.
With this in mind I went through every colour and decided what I felt it meant. I then looked at different shades of every colour to see what I thought then.
I soon had my 7 meanings and the darker shades of those 7 seemed to me to mean the colour was of more importance when stronger and less important when paler. So, I had my set of meanings.
Having tried them out on family and friends, I soon progressed to giving private readings using my ribbons. I do add to them occasionally, but I never add patterned or sparkly ones, as this interferes with the colour choice, in my experience. It then becomes too involved and it should be simple.
All this being said, I feel that white is a very childlike colour. It means to me that someone is being childlike, or perhaps naive. I always go with my feelings, clairsentience, to ensure I have it right.
So, if I were reading for you, and you chose a white flower, or if I saw a spirit give you a white flower, I would say that you were being naive in a situation. I would then ask spirit for more information to elaborate so that you knew what I meant.
White may mean something totally different to you. Only experience and experimentation will satisfy you. Above all, enjoy the experience!