Give your roses the attention they need to succeed and get ready for Spring!
September is almost as exciting as October because the roses are growing at pace, setting buds by the score and bursting with vigour and health. All the energy comes from the reserves stored in the stems over winter, and they almost don’t need us to perform. But if you want truly exceptional roses there is a way to help and harness that vigour, and I don’t know any gardeners who can resist that!
Spring strategies for stunning roses
Water deeply and often You can always cut back later. Because the roses are growing so fast their uptake of water is massive – you can see it in the juiciness of the stems and leaves. Watering well in September allows the roses to grow to their maximum potential, establish a strong root system and produce new basal shoots that produce the best blooms. With ample watering, stems will stretch and form healthy, full buds to provide quality picking roses.
How much? While this depends on the temperature and the soil type, our recommendation is deep watering (40 minutes) 2 – 3 times a week.
Top up with fertiliser
The rapid growth also uses up nutrients, and roses need a good balance of these, with a high proportion of potassium, to flower well. Fertilise towards the middle of September with 30g Vigorosa for hybrid teas, floribunda and bush roses, and double that amount for Panarosa, Spire and climbing roses. If the controlled release fertiliser Vigolonger was worked into the soil after pruning there is no need to fertilise, however the added ‘sweetener’ of Vigorosa will give them an extra kick.
Safeguard blooms against thrips
Thrips has become the biggest spoiler of rose blooms and new growth, and it has spread countrywide. These tiny insects suck the moisture out of the new shoots and buds, leaving them deformed and small. A thrips infestation can wipe out a rose flush and even affect future flushes. The best protection against thrips is the long-lasting systemic Koinor that is applied as a drench to each rose bush. It is a bit tedious and time-consuming to apply, but it is well worth the effort and the roses will be protected for up to six months.
Manipulate hybrid tea roses to flower for longer
This is done by finger pruning, which simply means pinching offthe tips of a third of the new shoots with your fingers. This is done in early September, just before the new shoots form the flower buds. Select new shoots that might be too close and in competition with each other, and pinch out the tip of one of them. Also pinch out those that look weak or are growing to the inside of the bush. Any number of shoots can be pinched but the general rule is that it should be a third of the new shoots. The newly pinched stems will flower about two weeks after the stems that were not finger pruned. This breaks the flowering cycle for the rest of the season and there should not be a day without at least one bloom on the bush. Finger pruning is not needed for climbers, ‘Colourscape’ varieties, ‘Icebergs’ and most of the floribundas.
Revisit your pruning
It is now very clear where new sprouting is taking place and where stems are too close together. Ideally, stems should be 20cm (the length of your secateurs) apart so that they have space to grow. Corrective pruning removes the superfluous stems, or those that are too close together. Cut back to a well-developed new shoot and not into the bare wood.