Why are My Rhododendrons Flowering Out of Season?

Rhododendrons are known for their beautiful blooms in spring, but what happens when they start flowering out of season? While this may seem unusual, it can actually happen for a number of reasons.

This is predominantly due to the current weather patterns. As we are still in an El Nina, this has affected the temperatures and the type of weather we have been having, which also affects the plants. For example, we have had really hot weather over summer here in Christchurch, then we had a period of 3 days where it was below 10 degrees, and then we are back to 20 degree days. Our blue dawn rhododendrons have put on a beautiful show of flowers for autumn as they were tricked into thinking that they had experienced winter.

In addition to weather patterns, other factors that can cause rhododendrons to flower out of season including changes in light levels.

So, if your rhododendrons are flowering out of season, should you be worried? The answer is no. In fact, some rhododendron varieties, such as the Black Sport rhododendron, are known to flower twice a year in the nursery, one in March and the other in late November. Even though the rhododendrons have chosen to flower in autumn, they will still often produce flowers in late October and November.

If your rhododendrons have already flowered out of season, it is important to deadhead them like normal. However, you should avoid pruning them as we head into winter, as any new growth could be destroyed by upcoming frosts.

To help your rhododendrons through this next period of growth, it is a good idea to give them a little bit of fertiliser. This can help them cope with any adverse weather conditions that they may face. Rhododendrons require a slow-release acidic fertiliser that contains magnesium and iron, and small amounts of fertiliser is more beneficial for the plant than large annual applications. Here at Rhododirect, we recommend dividing the suggested amount of fertiliser by three and applying a third just before flowering, a third just after flowering, and the last third in March. This reduces the risk of fertiliser burn occurring on the plants from applying too much fertiliser.

Regular watering is crucial to ensure that the fertiliser is being released evenly into the soil to feed the plants.  Coming into winter no as important as in the summer months.

While it may be surprising to see your rhododendrons flowering out of season, it’s not necessarily a cause for concern. By understanding the reasons why this can happen and taking appropriate steps to care for your plants, you can ensure that your rhododendrons continue to thrive and provide you with beautiful blooms for years to come.