Management methods and technical key points after rhododendrons bloom

Pruning and shaping: after rhododendrons finish blooming, the spent flowers generally need to be removed by hand, followed by appropriate thinning of branches, cutting away overly dense branches, and letting them send out new growth.

Fertilizer and water management: in northern regions, water is on the alkaline side and relatively hard, and watering plants with it over the long term can easily cause soil alkalization, affecting flower growth. Therefore, before watering, the water should be stored in a container for more than 24 hours and used after the chlorine has evaporated. Alternatively, water mixed with an appropriate amount of ferrous sulfate or edible white vinegar can be applied about once every 10 days. Rhododendrons do not need much fertilizer, and it is generally applied along with watering. From late spring to early summer, apply soybean cake fertilizer water once every half month, using light fertilizer frequently to encourage new buds to sprout and branches to grow. If soybean cake fertilizer is not available, you can buy some acidic flower fertilizer on the market and use it the same way. By mid to late June, some quick-acting phosphorus and potassium fertilizer can be applied to promote flower bud formation. By late autumn, stop fertilizing to avoid new shoot growth affecting flower bud differentiation.

Summer management: rhododendrons like a cool and humid climate environment. In summer and autumn, they should be placed in a shaded, ventilated spot, and clean water should be sprayed on the branches, leaves and surrounding area. You can also put clean water in a shallow tray, place the flower pot on the tray, and let the flowers slowly absorb water from the bottom of the shallow tray.

Flowering regulation: temperature has a great influence on the formation of rhododendron flower buds. Generally, flower bud differentiation begins above 15°C, the suitable temperature is 20°C-27°C, and the nighttime temperature should be kept at around 5°C. After most flower buds have formed, they need low-temperature treatment at 4°C-7°C for about 30 days before they can bloom. In addition, shading treatment is beneficial to flower bud formation and blooming.