Garden roses need attention in order to grow and flower optimally. It is important to give them the right nutrition and watering.
Roses are vigorous growers and will need to receive enough nutrients during their growing season. This will promote growth and flowering and strong plants. Fertilise garden roses in spring and summer.
Start fertilising in the spring, after the first pruning. Organic manure, such as dried cow manure, contains all the necessary minerals and trace elements. It makes the soil more airy and ensures better moisture retention. Lightly mix the fertiliser into the soil to avoid burning. For soil with a low PH (acidic soil), mix a calciferous fertiliser through the top layer once a year.
After the first flowering, in July, it is time to apply the second fertiliser. This can be done with special rose fertiliser if desired. This plant food is rich in potassium, which promotes intense flower colours and strong plants. The additional magnesium it contains results in a deep green leaf colour. Do not use fertiliser after August, so that the plant enters winter properly hardened.
You can recognise nutritional deficiency by light-green to yellow leaves with dark veins. If the rose needs additional fertiliser quickly, it is best to use chemical fertiliser. The nutrients in this kind of fertiliser are immediately available to the plant so they work faster than an organic fertiliser.
Pot roses on the balcony or terrace need regular fertilising because they can’t store nutrients as well as roses in the garden. If your pot rose is struggling and you can see it deteriorating, give it some new, fresh soil and add organic rose fertiliser.
Pests and diseases
Healthy plants that have sufficient resistance will be much less susceptible to pests and diseases. Nevertheless, in certain weather conditions, an insect infestation or a fungal disease may rear its head.
Aphids and spider mites are the most common pests on garden roses. They damage the plants by sucking out the plant sap. In small numbers, aphids are harmless. In fact, they increase biodiversity because many natural enemies such as hoverflies, parasitic wasps and ladybirds love aphids and spider mites. They usually keep aphid numbers limited.
Fighting aphids and spider mites
Nesting boxes for great tits and blue tits work wonders in the fight against aphids. Lavender is also a good, natural form of pest control, since aphids do not like the smell of lavender. If you are struggling to get rid of spider mites and aphids, try fighting them with a cold jet of water: they absolutely hate this. Another remedy for aphids is to spray your roses with a solution of mild green soap, water and some denatured alcohol.
These are the most common fungal disease in roses:
- Mildew: these are white spots on the leaves and flower buds
- Rust: these are orange spore clumps on the underside of the leaves
- Black spot: results in yellow leaves with purple-black spots at the bottom of the shrub.
The main rule for fighting fungi is: ‘prevention is better than cure’. Fungi need moisture to develop. This is why it is best to water at the base of the plant, so that the leaves stay dry. You can also give your rose shrubs a helping hand by spraying them with organic plant invigorators. They make the plant stronger, so that fungi do not have a chance to infect the roses.
To prevent fungi, make sure your roses are dry before night falls by only watering them in the morning or in the afternoon. Spray the water near the soil at the base of the rose shrub. If you have just planted a garden rose, make sure you give it extra water for the first few weeks, and keep an eye on it to prevent the plant from drying out. If the rose appears to be growing happily, it means that it is seeking out water by itself, through deep rooting. When this happens, there is no need for additional watering. An extra splash will only be necessary during long dry periods.
Protection from frost
When the temperature drops below -10 degrees Celsius, roses need protection. If you expect the mercury to get this low during winter, make sure you prepare your garden roses for winter in November.
- Garden roses
Prevent freezing of the grafting site by earthing up the shrub. This is done by creating a mound around the stem of the rose with compost or garden soil.
- Standard roses
With standard roses, the grafting site is at the height where the branching of the crown begins. Therefore, wrap the entire stem and the crown with straw, fir branches or burlap.