Q: The 25-year-old Aloha rose in our garden is not blooming anymore, it used to fill June with its blooms. What would you suggest for it to flower once again? A Forsyth
A: It’s a well-known fact that roses, a widely recognised and loved flower species, can be susceptible to various pests and diseases. They are often the targets of harmful fungi like black spot, powdery mildew, rose rust, and more, leading to discolouration, malformation of leaves, reduced blooming and sometimes, even death. Factors like unsuitable soil conditions that are either too dry or too wet, and a lack of nutrients, as well as damage from incorrect pruning techniques can seriously affect the health and vitality of the plant.
The Aloha rose in question is characterized as a moderate climber and is renowned for its large, double, fragrant, and coral-pink flowers. Generally, it’s seen as robust and prolific in flowering. Being content in direct sun or light shade, it usually grows to a height of 3m to 4m (10-13ft). It’s challenging to pin point the exact reason for its apparent sickness, however, creating optimal growing conditions can enhance its chances of recovery, much like humans.
For roses, that are demanding and need frequent hydration, providing a deep, fertile, nutrient-rich, moist, and freely draining soil is ideal. Hence, a hefty mulch of well-rotted manure or home-made compost should be added around the roots yearly in late winters or early springs, along with a slow-release organic pelleted fertiliser. Proper pruning plays a vital role in maintaining the health of most roses. For climbing roses in particular, pruning should be performed from December to February, and the side shoots and tips of main branches should be shortened as per mentioned lengths.
Regarding the unwell plant, it would be advisable to heavily prune it to a length of 15-20cm from the root, come the onset of the ensuing spring. This should be complemented by extensive mulching, nourishment, and hydration. Be sure to collect and dispose of all the pruned and fallen leaves as they could possibly lead to a resurgence of disease. This rigorous pruning accompanied by considerable mulching, feeding and watering will get rid of all diseased, rotten or impaired wood, effectively stimulating the plant to sprout robust new branches from the root.
After the plant recovers and grows actively, supplying it with regular liquid feeds using Uncle Tom’s Rose Tonic can be greatly beneficial. Just bear in mind, if the plant has been infected by a fungal disease originating in the soil, nothing can salvage it. Only time will reveal the outcome.