Prune 'n' bloom azaleas

Nothing signals spring like vibrant Kurume azaleas, and summer pruning is the secret to their stunning floral show.

Kurume azaleas may have smaller flowers than common Indian azaleas, but they compensate with an abundance of blooms per stem, creating a breathtaking spring display with the right care. Unfortunately, many gardens today fall short of this potential due to a lack of knowledge about the Japanese techniques used to maximize their flowering.



The secret lies in meticulous pruning, feeding, weed control and ongoing maintenance. Pruning at critical growth stages throughout the year is essential for achieving these stunning results.





This spectacular display of flowering Kurume azaleas can be seen at Shiofune Kannon-ji, affectionately known as the 'temple of flowers' in Tokyo. There are over 20,000 azaleas on the temple grounds.

 

How to grow Kurume azaleas

All azaleas are hardy plants suitable for pots or the ground, but Kurume azaleas stand out for their exceptional toughness. These compact bushes, reaching sizes of 1.5m tall and 2m wide, boast a resilient root system. Their natural habitat provides insight into their preferred growing conditions: small soil pockets in well-drained areas of warm to cool temperate forests, often shaded by trees that allow for dappled light. Here, crevices fill with leaf litter and organic matter, creating an acidic, nutrient-rich soil with a pH of 5.0 to 6.0.

  If your soil is sandy, add copious amounts of organic matter in the form of compost and quality cow manure to retain moisture and nutrients long-term. For heavy clay soils, do the same but also add scoria, grit, or coarse washed river sand to improve drainage.







Kurume azaleas come in a vibrant range of colours from bright pinks and deep reds to pure whites and purples.



  While raising beds wasn’t needed in our rockery, it’s essential for flatter ground. Use stones, logs, or sleepers to create raised beds about 30cm high to enhance drainage. Even a week of heavy rain can waterlog your azaleas, leading to their demise.

  Feeding is also critical to maximize flower production and discourage diseases. I apply an acid-loving fertilizer, like Neutrog's Kahoona, after flowering, again in December, and repeat in February and March. By then, the bushes will be in the early stages of budding.

  I mulch throughout summer with cow manure or Neutrog's WhoFlungDung, but never with mushroom compost, as lime is often used in its production and is deadly for azaleas.

  Several weeks after flowering, new shoots will appear over the entire bush. Once they reach 2–3cm, prune them with hedging shears or a motorized trimmer, shaping the bush into a formal, rounded shape as you go. Feeding will encourage at least one to two more growth spurts, which must also be sheared off, but it’s essential to stop all pruning in late January as embryonic flowers will be forming.

  Red spider mites, or two-spotted mites, are pests of all azaleas. I use a combination of Richgro’s Bug Killa Granules every 7–8 weeks after flowering and spray with Multicrop’s Eco Bug Organic, ensuring thorough coverage on both sides of the leaves.

'Christmas Cheer’ in full bloom

Graham’s top Kurumeazaleas for you

• AZALEA ‘CHRISTMAS CHEER’, a crimson-red and compact grower.

• AZALEA ‘KIRIN’, a deep rose-pink with a double hose-in-hose flower.

• AZALEA ‘WAKAKAYEDE’, bright cerise-crimson, small single, withstands full sun.

1. Prune new growth once it reaches 2-3cm with hedging shears or a motorised trimmer. Continue throughout the season but stop in late January.







2. When pruning, trim to create a neat, rounded shape