isn't green a colour used in therapy?
I have heard that it is very relaxing, gives a 'back to nature' feeling?

Yes green is used in colour therapy both for connecting to nature and to bring growth and prosperity into life.

what other colors are used in color therapy?

Colour Healing

Colours are a simple way to bring great changes in your daily life. Most of you might have noticed that walking into a soothing blue room will immediately relax your muscles and get rid of stress. Colours have such impact on us, no wonder they aid learning and of course traffic signs! Taking time to look at the colours in your life and using the right colours to attract the right things isn't that hard really! Here is a list of some common colours and what they can do for you. Remember to use them in balance! If you feel overenthusiactic, maybe you should check the amount of yellow in your life, but on the other hand, if you feel a lack of energy, include some yellow in your room or at work. In this article, we are going to focus more on the healing effects of colours on the emotional level than on the physical level.  The following are just general meanings of colours, you might find that you associate differently with different colours, for this, use meditation to find the colours you feel pulled towards for any particular healing.

Yellow
Stimulates brain and nervous activity. Energizes the muscles. Activates and cheers updepressed and melancholic people.

Orange
Shows new possibilities and other options in life. Stimulates creative thinking and enthusiasm.

Red

Brings warmth, energy and stimulation. Increases sexual desire and activity.

Green
Brings psychological and emotional harmony and balance; calms your heart and can be associated with relationsips. enourages rejunation and is good for money and prosperity. Cleans and purifies.  lends enthusiasm, hope, sharing, growth, expansion.

Indigo
Helps bring about qualities like serenity, calm, balance, humanitarian and world service, synthesis and aspiration.

Violet
Reveals mercy, devotion, loyalty, idealism, wisdom and grace. Represents the highest element in human nature.

Pink

Heals grief and sadness. Restores youthfulness. Brings you in contact with your feelings. Associated with self love, great to heal lonliness and feelings of unwantedness.

uses of colour healing


   * Use colored lights or candles for a few minutes each day.
   * You can hang up pieces of cloth or paper sheets in the desired color in the room.
   * You      can fill colored glasses or bottles with (spring)water, place it in the
     window for at least three hours and drink three glasses a day of this
     water.
   * You can wear clothes in certain colors.
   * You can visualize colored light in and around your body, breathe it in and direct it to the body-parts that need it.
   * Wear jewelry with gemstones in the colors you need.
   
You can also use Coloured candles as a part of color healing. The most common uses for some common coloured candles are listed below.

Black  -  destruction of negative energy and confusion.
Blue   - honesty, healing,. meditation, forgiveness
Brown - study, balance, concentration.
Green -  healing, prosperity, luck.
Lavendar - Intuition,  opening of the third eye.
Orange - Strength,  attraction, joy, success, friendship
Pink  - Emotional love, freinds
Red   -   Love, passion, courage
White  - Protection, purity, clarity
Yellow -  communication, enthusiasm, opening to spirituality

And last but not the least, colours can be used to balance or open up chakras.

From Spiritualblessing.org