What to do with rhododendrons and azaleas in the fall – expert tips to prepare your shrubs for the colder months
Everything you need to know about how to care for these spectacular flowering shrubs in the fall
The Rhododendron genus is a large group of over 1,000 different species. Most of these are native to Asia, particularly the Himalayan region, but a small number grow closer to home. The Pacific rhododendron, Rhododendron macrophyllum, is found growing along the West Coast of North America, producing masses of Barbie-pink blooms that are striking when seen in a woodland environment in the State of Washington, Oregon or California.
Whatever species you grow, whether it is a native azalea or a rhododendron from mountainous terrains far away, it is important to know how to care for your plant during the fall. As with all seasons, fall is a time of great change, with balmy, mild days giving way to heavy rainfall and harsh frosts, often in rapid time.
As a former professional gardener, I have grown rhododendrons and azaleas in many gardens where I have worked across the UK. While these popular shrubs are easy to maintain, a few simple steps completed in the fall will ensure your plants produce plenty of flowers next year. Here, I share all I know to get the most out of your prized shrubs.
What to do with rhododendrons and azaleas in the fall
During fall, rhododendrons and azaleas require specific care to ensure that they thrive the following spring and summer. In October and November, it is a good idea to mulch your borders, tidy your plants and monitor watering. By following these simple steps you will get the most out of your flowering shrubs in the years to come.
1. Mulch rhododendron and azalea shrubs
Mulching in the fall is a good idea as it will help protect your plants during the colder months of the year. This is particularly important in cooler US hardiness zones, such as zone 4 or 5. What's more, mulching will help keep weeding to a minimum, which is helpful during the fall when the wet weather can result in ideal growing conditions for many vigorous weeds.
Add a layer of mulch around the base of your rhododendrons and azaleas anytime in October or November, doing so before winter gets underway. Organic products, such as this pine bark mulch, make for an excellent mulch that will support the ecosystem in your yard and insulate the roots of your plants.
I suggest applying a thick two-inch layer of mulch around the base, ensuring that the mulch doesn’t touch the trunk of your rhododendrons or azaleas directly as this can cause rotting.
This mulch will help your shrubs to maintain healthy root systems by protecting them from frost, cold and direct sun in the summer. What's more, this mulch improves the structure of your soil.
2. Lightly prune your rhododendrons and azaleas
Lightly pruning rhododendrons and azaleas in the fall will ensure they remain healthy and in good shape. I suggest removing any dead or diseased branches, which should be easy to spot. These branches will have few if any leaves, and will often appear rotten or blackened in color. For thicker branches, it is best to use a sharp pruning saw, available from Walmart, cutting down to a healthy stem or shoot.
I also recommend a final spot of deadheading, removing any remaining spent blooms. This will prevent the shrub from expending energy on seed production, and also ensure that you do not have masses of seedlings to remove in the spring, unless, of course, you are looking to propagate rhododendron plants in your yard.
Simply deadhead azalea and rhododendron shrubs by snipping any faded blooms or seed pods down to the stem, using clean and sharp tools such as these Felco pruners, available from Amazon.
3. Water rhododendron and azalea shrubs deeply
Much the same as caring for rhododendrons and azaleas in summer, watering these woodland shrubs in the fall is crucial. While they don't require an excessive amount of water, ensuring the soil is moist before winter sets in is a good idea.
'Rhododendrons and azaleas are typically woodland plants,' says Kathy Jentz, azalea expert and editor of The Azalean, 'meaning that they thrive in moist soils. For this reason, supplemental watering through late summer into early fall will ensure that your plants have what they need for the dark, cold months ahead.
'It is best to follow the deep watering approach,' Kathy advises, 'with infrequent but thorough waterings far preferable to smaller amounts.'
Fall can be an incredibly changeable season, with periods of warm and dry weather making watering an important job to add to your fall gardening checklist. The amount of water will vary depending on your soil and the weather, but I would always tend to suggest at least two or more cans to reach the roots far underground. Purchasing a good quality watering can is a long-term investment I cannot recommend enough, such as this galvanized steel watering can, available from Amazon.
Kathy Jentz is the editor of The Azalean Journal, as well as the editor and publisher of the award-winning Washington Gardener Magazine. She is also the editor of two other plant society journals: the Water Garden Journal (IWGS), and Fanfare (Daylily Society Region 3).
FAQs
What is eating the lower leaves of my azalea?
If leaf damage is restricted to the lower leaves of your rhododendron or azalea plants, it is often the result of hungry deer passing through your yard. If you have a large shrub, this is not typically a problem, as they will not be able to reach the upper canopy. However, for smaller shrubs, it is a good idea to deter these pests, by using something like these organic peppermint repellent balls from Amazon.
One final word of warning is to never feed your rhododendrons or azaleas in the fall. This is a common fertilizing mistake but should be avoided at all costs. 'Feeding in the fall can encourage your plant to produce new growth which will then be killed during winter,' Kathy says. 'It is best to leave fertilizing to the springtime.'
Sign up to the Homes & Gardens newsletter
Design expertise in your inbox – from inspiring decorating ideas and beautiful celebrity homes to practical gardening advice and shopping round-ups.
Thomas is a Content Editor within the Gardens Team at Homes and Gardens. He has worked as a professional gardener in gardens across the UK and Italy, specializing in productive gardening, growing food and flowers. Trained in Horticulture at the Garden Museum, London, he has written on gardening and garden history for various publications in the UK, including The English Garden, Gardens Illustrated, Hortus, The London Gardener and Bloom. He has co-authored a Lonely Planet travel book, The Tree Atlas, due out in 2024.
-
7 different interior designers on ingenious ways they use paint to easily elevate a room
Paint can be the easiest way to transform a room, here 7 designers talk us through how they use it to the best effect
By Arabella Youens Published
-
How to take mulberry tree cuttings – expert tips for successful plant propagation
Learning how to take mulberry tree cuttings is a cost-effective way to grow your tree collection
By Thomas Rutter Published
-
How to take mulberry tree cuttings – expert tips for successful plant propagation
Learning how to take mulberry tree cuttings is a cost-effective way to grow your tree collection
By Thomas Rutter Published
-
I have planted thousands of perennials and shrubs as a professional gardener – and biochar is the secret ingredient I always recommend
Biochar is a helpful and long-lasting soil additive, with impressive results
By Thomas Rutter Published
-
Is collecting fallen leaves always essential? Discover where never to leave them, and the places in the yard where it's safe to do so
Should they stay or should they go? We advise, and highlight the best leaf-collecting tools for the job
By Drew Swainston Published
-
I have planted more than 10,000 bulbs as a professional gardener – and these are the best tools for the job
These bulb planter deals will help to minimize effort and maximize productivity when gardening in the fall
By Thomas Rutter Published
-
Should I cut back asters in the fall or wait until spring? The choice is yours, and here’s how to decide
Which side are you on when it comes to cutting back asters? Our guide will help you to pick
By Drew Swainston Published
-
Seeds to collect in October – 7 flowers and vegetables to harvest seeds from this month
Get ahead for next year by collecting seeds, and discover tips for how to harvest and store them
By Drew Swainston Published
-
How to stop soil freezing in winter – to protect soil and plant health
Frozen soil can hinder your plants' ability to grow
By Tenielle Jordison Published
-
Best fall-flowering perennials – 7 expert-approved blooms for late-season color
Fill your yard with vibrant seasonal color by growing some of the best fall-flowering perennials
By Thomas Rutter Published