Re: What does ammonia do to roses?

Whilst I can't talk directly about roses I can comment on the effect of ammonia and other strong basic chemicals (such as sodium hydroxide) on flowers in general.

The colour of flowers and any part of the plant (in your case roses) is determined by the plant pigments found in that particular part of the plant. Plant pigments are complex chemicals made by the plant in order to do a whole range of biological processes for the plant, including attracting (or distracting) insects and birds and for creating energy by photosynthesis. The primary plant pigments are chemicals in the classes : chlorophylls, carotenoids, phytochromes and flavonoids; some of these pigments can be affected by ammonia in a way that the colour that we see them as is changed.

What happens is the ammonia reacts with the plant pigment and changes it's chemical structure so instead of seeing it as a red colour we see it as a blueish colour, you will find if the source of ammonia is removed then slowly the plant will change back to its original colours.

If you interested in some of the complex chemical structures that make up plant colours you can check out this page on chlorophylls. Whilst the structure might not mean much to you, its large and has lots of sensitive functional sections that could be affected by ammonia

Well I hope that helped you out,

David Barker