Mistakes to Avoid When Growing Rhododendrons

There are message boards all over the Internet with people asking desperately, “What am I doing wrong??” when they discuss growing their rhododendrons. Many of the mistakes made are done so unaware—that is, gardeners don’t know they’re making a mistake in the first place. There are common mistakes, and then there are some that aren’t so common. Either way, here are some mistakes you can avoid when you’re growing your own rhododendrons.


Rhododendrons love moist soil; however, they can’t handle mud. This will make the roots rot and will ultimately kill your plant. (Yes, kill; not just stunt it.) It’s a simple thing, but it’s often overlooked, especially in gardens that require more than one distinct watering regimen.

To avoid overwatering, walk over to your rhododendron and stick your finger in the ground. If the soil is moist, leave it alone. Give it a day or so before you water it again.

Poor Fertilization

Another thing rhododendrons like is acidic soil. Using the wrong fertilizer can lower the soil’s acidity; don’t use lime or other alkaline fertilizers. You should keep the soil’s pH level to about 5.5, thus cultivating the acidity.

Also, if you can, use gentle, organic fertilizers. Rhododendrons are susceptible to chemical burn, and so something like fish or seaweed fertilizer is ideal, even if the fish or seaweed is just an additive to another organic compound.

Careless Weeding

The root system of a rhododendron grows shallow and wide, and when weeds get involved with a rhododendron, the two root systems can sometimes tangle up and even combine. This is why weeding with care is so crucial—if you rip up a weed, you might bring some of your rhododendron’s roots with it. This can stunt the growth of your rhododendron if you’re not careful.

Bad Drainage

It was mentioned before that rhododendrons like moist soil. Moist, however, isn’t soaking wet, muddy, or watery. If the plant isn’t properly drained, or planted in an area where water can escape, your rhododendron will definitely end up with root rot. This will also kill your plant. Keep it drained!

Poor Sanitation

When you clean up after your plant, not only are you giving it room to grow but you’re making it safe to grow. Leaving dead plant matter on your rhododendron can actually attract fungal infections, as well as parasitic infection. The best way to avoid this mistake is to deadhead and trim dead or dying branches when you notice them. Good sanitation will give your rhododendron the clean environment it needs for flourishing.

Poor Circulation

If the leaves of your rhododendron can’t reach the indirect sunlight required, they can’t photosynthesize (make food from sunlight). This creates one problem, and is one reason why pruning and trimming back the plant is so important.

Another is air circulation. Water doesn’t have the opportunity to dry on the surfaces of the leaves if there is too much foliage in the way of air moving through the plant. Rather than let the leaves and flowers turn to mush, keep the rhododendron trimmed, so that air can move through and speed the water evaporation process.

While these mistakes are common, not everyone knows not to make them. With a little studying and the application of what you’ve learned, you too can care for your rhododendron, mistake-free.