Caring for your roses

KJ Reyland | 19 October, 2021

            Pruning and caring for roses

Roses must be fertilised and watered during the growing season. If possible, apply a mulch of clean compost or fine bark chips. Composted bark chips that are now available, are excellent for roses. Light surface hoeing to remove weeds is advised where necessary.


Roses are gross feeders (meaning they require feeding little and often) and should be fertilised in September and February, with a well balanced rose fertiliser. The following are recommended. 

  • Tui Novatec premium fertiliser
    • N 15, P 1.3, K 16.6 plus magnesium and trace elements.
  • Yates Granular Rose Food
    • N 5, P 5, K 10, plus sulphur, magnesium and trace elements.
  • Tui Rose Fertiliser
    • N 5, P 4, K 8, , plus sulphur, magnesium and trace elements.

The above N P K values represent the ratio of nutrients: nitrogen (N), phosphorus (P), and potassium (K)


During dry weather it is important to keep roses actively growing by regular watering. If they do not get adequate moisture, they will fail to thrive. To minimise disease, avoid overhead watering. A weeper soak hose is a much better option than sprinklers. These soak hoses easily connect to click on hose systems or irrigation polytube hose.


Modern roses can take harder pruning than the older types.

For the Old Garden Varieties, all that is necessary in the main is the shortening back of long, vigorous canes by approximately one third, and the removal of old, dead and dying wood, and central weak spindly growth. If in doubt, seek advice from your garden centre. There are many excellent books now available on the cultivation of old roses.

Pest & Disease Control

Many of the newer roses have a level of disease resistance, but in most cases a regular spray programme through the growing season will be necessary. Prevention techniques that will minimise the spraying required are –

  • Use a rose fertiliser as above which is high in potassium (K)
  • Keep rose plantings well ventilated. Do not allow overcrowding.
  • Do not use sprinklers or overhead watering. Weeper soak hoses are preferred.
  • Remove diseased foliage promptly and destroy.
  • If intervention is required with a pesticide do so promptly. In many situations a preventative programme will be required.

Yates Super Shield, Combat, and Kiwicare Spectrum are all moderately good rose sprays. They all contain the fungicide myclobutanil, and the insecticide tau-fluvalinate. This combination will control black spot, powdery mildew and rust when applied at very first sign as a protectant. It will also control aphids, thrips, mites and chewing insects. (Downy mildew, scale and mealy bug are not controlled).

It is important to correctly identify the problem as a more specific pesticides may be required. Click here to see a chart for rose pests and diseases -coming soon!