Hello, and welcome again on another one of my articles! If this is your first time on our website, go on, take a look, and please, enjoy yourself! Amateur or hardcore gardener, it doesn’t matter! All that counts is our love for plants!
If you’re on this article specifically, it means you’re wondering how you can start to grow Rhododendron flowers (even though their name sounds like a villain from Dungeon & Dragons), and hell, aren’t we all? Which is why we’ve prepared this whole guide for you: you’ll know everything about planting the spectacular rhododendrons (or azaleas), from preparing your soil, to watering your plants, to fertilizing them and taking care of them.
So friend and fellow gardener, follow this article, and become an expert in rhododendron flowers (damn this word is so difficult to write!).
A few things you need to know about rhododendrons first
Where do rhododendron flowers come from?
Rhododendrons are beautiful flowers (that can be pink, white, purple, or red) that are part of the Ericacea family (which also includes blueberries, cranberries, heathers, mountain laurels, and a bunch of other plants). They are known as the King of Shrubs since many people see them as the best flowering evergreen plants for the temperate landscape.
They are mainly found in Asia (they are also the national flowers of Nepal), even though they also grow in the highlands and in some parts of Northern America. Most species of rhododendrons have showy, colorful flowers that bloom from late winter until summer.
A bit of history for you all: Even though they’ve been growing in the highlands for quite a while, they weren’t discovered until the 16th century by a Flemish botanist named Charles l’Ecluse (even his name is fancy).
I’m confused: what is the difference between rhododendrons and azaleas?
Believe me, you’re not the only person who is confused by botanical terminology (so I am, and I’m a writer, words shouldn’t confuse me!)
As it turns out, rhododendrons and azaleas are both part of the genus Rhododendron (again, confusing!!!!). The difference between them is that rhododendron flowers are evergreens while azaleas are known to be deciduous (which means that they shed their leaves annually).
There is another difference, which is while rhododendrons have ten or more stamens, azaleas only have five of those.
What else should I know before planting rhododendron?
Well, you should know that these beautiful plants can pretty much grow everywhere in North America, from the coldest cities in Canada to warmest places such as California or Florida.
Thousands of rhododendrons exist, which is why there is a type for every situation and place. You can have bushes as small as 2 feet tall or as big as 25 feet. Yes, 25 feet, pretty impressive, right?
Most of these plants bloom during the spring, but, worry not! If you’d prefer your garden to be full of bright colors and life during the summer, there are some rhododendron varieties that can do that too!
How to grow rhododendron flowers
As I wrote earlier, rhododendrons should be planted either during the spring or early fall, which both offer an optimal blooming and the promise of a magically colorful garden! But in order to do this, you’ll need to follow some steps.
Worry not, they’re simple and we’ll be helping you along the way. So, let’s get into business!
First, choose the right spot for your plants
Where to plant your rhododendron is a good question that every fellow gardener should ask. As we know, each kind of plants has its preferences; some love full sun, some prefer to stay in the shade or indoors. So, what about rhododendrons?
Well, those beautiful creatures need to be planted somewhere that is sheltered from sun and wind (which helps your flowers to bloom for longer). However, avoid planting your new rhododendrons next to already established trees, as they could take all the moisture from the soil and leave nothing for your newly planted rhododendrons.
Second, prepare your soil
Preparing your soil isn’t just important, but primordial if you want a beautiful growth (and who doesn’t want that, right?). Well, today is your lucky day, since we’ll be telling your everything about how to prepare your soil for growing beautiful, colorful, and most importantly, healthy rhododendron flowers.
These plants are known for being pretty trouble free, but only, and only if they’ve been planted properly, which is why this step is so important. Early fall is the best time for planting rhododendrons (even better than spring), and those plants generally like a lime free soil that’s always hydrated.
In order to provide your rhododendron with the best type of soil, you should check your soil’s pH (or acidity) level (you can use a soil pH meter). Those plants love acidity, which is why your soil should be well drained and with a pH of 4.5 to 6. If it’s not, we suggest you make your soil more acidic by adding to it sphagnum peat or a fertilizer that contains ammonium sulfate. You can find more information about how to make your soil more acidic by clicking here.
Once your soil has the right pH, you can go on and plant your rhododendron.
Third, plant your rhododendrons
First, be sure to clear your site from any perennial weeds and grasses (since they might hurt your newly planted rhododendrons). Always think about digging a very wide hole, preferably one that’s two or three times bigger than the root ball you will be planting.
Mix in plenty of compost, one that’s made of rotted leaves or pines needles (if you make your own compost) and never, ever, use animal manure or mushroom compost which are too strong and limey for your rhododendrons.
You can also use industrial or homemade Ericaceous compost.
Then, go on and plant your rhododendron flowers. Avoid planting them too deep, rhododendrons hate that! It would be better to plant to top of the root ball at above ground level and then add 50 mm mulch to keep your soil moisturized and insulated. This mulch also helps reduce weed growth. It’s also better not to use weed suppressants or gravel mulch, as they can negatively affect aeration, drainage, and temperature.
Taking care of you rhododendron
Now that you have planted your rhododendrons, you have to learn how to care for them, so you can always have a healthy and well fed plant in your garden. Caring for rhododendrons is easy, and comes in three parts: watering, fertilizing, and pruning.
How to water your rhododendron flowers
When you plant rhododendrons or azaleas in your garden, you have to take their original natural habitat into consideration, and then, imitate their growing conditions as well as you can. Don’t just water your rhododendrons now and then, you have to do it in a regular way, and most importantly, you have to take care of your plants during the summer and the cold winter.
During the cool of the morning, water your rhododendron flowers up to 1 inch of water per week during the summer in the first three years after planting, but don’t overwater them, as it can cause your rhododendrons’ roots to rot and die (which is why we suggested your soil to be well drained).
After your plant matures, reduce its watering to 1 inch every two weeks during the summer, but if the root-area soil dries out between two watering sessions, go on and water your plant.
Come September though, you should taper off watering your rhododendrons, as they enter their dormant phase, and require less water. And during the winter, stop watering all together. You can resume watering your rhododendrons during the spring, when you see new growths appearing.
And here you go! Now, you know how you can water your rhododendrons properly without hurting them or over-soaking them.
How to fertilize your rhododendron
As long as your rhododendron bushes are planted in fertile soil, fertilizing them wouldn’t be necessary. But, fertile soil can be rare. So, if your soil is poor in nutrients but you still want your rhododendrons to bloom colorfully, here is how you can feed them:
Rhododendron fertilizer is the way to go. Generally, this kind of plants needs three important nutrients: nitrogen, phosphorous, and potassium. Rhododendron fertilizers have these ingredients in them (if you read the label, they will be listed as: N-P-K).
You can start fertilizing your rhododendron bushes at planting time, and after that, do it every early spring (when the buds start to swell). The trick here is not to give your plants too much fertilizer, as it can do more harm then good, and make your rhododendrons sick. This is why you should use a light hand, and most importantly, follow the instructions on the fertilizer’s label.
How to prune your rhododendrons
The best time to prune your rhododendron bushes is during the late winter, when the plants are still in their dormant phase. Although rhododendrons often need little to no pruning, it is always good to do a maintenance pruning now and then, to keep the plant young and full of life.
If you want to know exactly how you can prune your rhododendron bushes, check out this video!
Some rhododendron species
Like every plant, the rhododendron comes in different species. Here are some of them:
The rhododendron PJM is a hardy hybrid that can cope with the coldest climates and tolerate near neutral soils. It’s an evergreen specie that gives beautiful pink flowers during its blooming season. They also attract all kinds of butterflies, which means that your garden will be one of a fairy tale castle (without its evil queen of course).
Commonly known as the rosebay rhododendron, this evergreen specie is native to Eastern North America, and produces purple and pink to white flowers during early summer (from June to July).
Also known as Catawba rosebay, this specie of rhododendron is a native of Appalachian mountains, and beautifully blooms during spring time.
Nova Zembla rhododendron
This is a dense-growing, evergreen, colorful specie of rhododendron. It is mostly known for its mid-spring flowering, and tolerates the cold better than other species of rhododendrons.
The Rhododendron Indicum, also known as Satsuki Azalea, is native to Japan, and mostly comes in shades of hot scarlet red.
Like every other plant, the rhododendron is not free from pests and diseases, some of which we will give you the solutions here!
If your rhododendron leaves are suffering from this, it is most probably because your plant is too dry, too wet, planted too deep, needs feeding, or is planted in alkaline or neutral soil instead of acidic. If your soil’s drainage is poor, it is primordial to improve the soil’s structure or move your plant to a better drained soil.
If you see pale spots on your plant’s leaves with brown or grey patches underneath, then it’s probably suffering from a fungal disease. The best thing would be to apply fungicide on your rhododendron bushes from late May onwards.
If you see that your rhododendron’s leaves are eaten, then you probably have some kind of pest living in or near your plants. It could be caterpillars, scale insects, or aphids. The best way to get rid of them would be using a pesticide, even though you shouldn’t use too much of it as it can hurt your plants.
If you want to know more about rhododendrons problems and diseases, check out this website.
And don’t forget …
Plants and flowers need care to grow healthy and beautiful, just like any other creature. So be sure to feed, water, and prune your rhododendrons!