Plant Doctor Archive

Bringing out the colour in roses

Is it true that putting lime around your roses brings out the pink, and aluminium sulphate brings out the blue? I've tried it and it seems to work.

It may just be incidental that you've had better roses that particular year — I know roses grown in Queenstown have far more intense colour (and less insect pests) than roses grown in Auckland because the environment is far more favourable down there than in Auckland which is humid. A really cold winter can produce roses with more intense colour.

Environmental factors such as light and temperature are likely to have more of an effect on roses than aluminium sulphate or lime.

The higher the nitrogen content, the faster the growth, the more washed out the flower colour. More potassium, the better the flower size, colour and form. Regular feeding, watering and care will enhance the quality of flowers.

Advice by Dr Dan Blanchon from Unitec's Diploma in Sustainable Horticulture and Bachelor of Resource Management.

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