At some point each spring I have to pay homage to our Washington state flower, the Rhododendron. We are in the midst of April and heading towards May soon, which means that the glorious time of year has arrived for Rhodies to shine in all of our landscapes. My wife and I pause each spring to admire the larger ones we inherited in our garden some twenty years ago when we bought our home, along with the newer ones that we have continued to add over the years. Each one has provided gardening memories every spring and helps keep the bees happily buzzing about their flowers. Our admiration of them will continue year after year without a doubt, and I am sure that I will inevitably find another spot or two to add more.
Here in the PNW we have the perfect climate to grow Rhododendrons. Our regular spring rains, acidic soils, and plentiful woodland gardens all provide exactly what these beauties need. Keep a few things in mind when considering Rhododendrons, both old and new…
Drainage is a must, like with most plants, so be sure that they are not sited in wet winter areas or clay. Amending with compost can help, especially a bagged product with some built in acidity.
Pay attention to your location – sun or part sun or shade. Selecting the proper cultivar for your space is critical. Choosing the wrong one means either sunburn (too much sun) or a leggy and unsightly growth habit (too much shade).
How big is your spot? There are varieties in all kinds of heights and spreads, so be sure to pick the right size for your needs. From taller tree-like specimens to bushy spreaders to small dwarfs, there are lots of options with Rhododendrons. Bigger growers can even be limbed up and plants grown underneath them, as I have done in my yard over the years.
Be sure to apply mulch - either compost or bark is fine. If you do bark, be sure to put extra fertilizer under it as this will help counteract the loss of Nitrogen from the bark decomposing over time. Also be cautious not to bury plants too deep at the crowns.
Feed your Rhododendrons with an organic food once in March and again in June, for maximum health. If you really want to up your flower power, put down E.B. Stone’s organic Ultra Bloom (0-10-10) in June as well, as this will really help your plant set more buds.
In summer, ensure your Rhodies do not become drought stressed. They are by no means drought tolerant, but they also don’t need excessive irrigation. Older plants will need less water and newly planted ones will need a bit more the first summer or two. Proper mulching (described above) will help with this.
Remember that Rhododendrons are old-wood bloomers, thus their flower buds are set each summer for the following spring. I always mention this for a number of reasons… Feeding them in June, keeping them watered in drier summer months, and never pruning them in summer, fall or winter means maximum flower power. Prune them after bloom only, allowing the plant to regrow over summer and set flower buds for the next year.
Every spring I feel the need to name a few exceptional cultivars worthy of garden consideration. All Rhododendrons sport spectacular flowers, but each of us gardeners tend to gravitate toward specific colors, so find what speaks to you. Foliage will also vary, and I always recommend choosing the leaf that matches your style as well. Some have lovely new growth color, some add velvety indumentum, and even a few boast striking variegation.
‘Taurus’: The classic red with large foliage and flower that blooms in April. Give this one room since it is a larger growing specimen for part sun and part shade.
‘President Roosevelt’: A great red and white bicolor April flower for morning sun. These have variegated yellow on green foliage to add even more interest.
‘Songbird’: A lovely dwarf with small sun-tolerant foliage. These stay compact and sport lovely violet-blue flowers from late March into April.
‘Dark Lord’: A fun and whimsical deep red (almost black) flower in April. These will take some sun, but will grow best in the part sun/shade.
‘Cunningham’s White’: A classic April to May bloomer that has white blooms, growing thick and bushy with a spreading habit. Has excellent foliage and adaptability to sun or shade.
‘Daphnoides’: An unusual foliage Rhododendron with light purple flowers in May. Very versatile for sun or shade, and its cupped, Daphne-like leaves are unique.
‘Horizon Monarch’: One of my favorite yellows, with large foliage and huge flower trusses. Best in morning sun/afternoon shade, and be sure to give it room to spread.
‘Teddy Bear’: A lovely Yak hybrid with cinnamon indumentum on the foliage. Pink buds open to white blooms in April and it does best in morning sun/afternoon shade.
At Sunnyside Nursery, we partner with the American Rhododendron Society to host our annual Rhododendron flower truss show on Saturday, April 26th, from 10am to 2pm. The local Pilchuck Chapter of the ARS will be displaying flowers here on site and available to talk all things Rhodies with visitors. We also have a huge selection of what I would call “collector” Rhododendrons for sale in one-gallon pots from the Pilchuck Chapter. To clarify, these are not “collector” flavors that are hard to grow, but rather ones that are more rare and hard to find among the 5,000+ named hybrids. Yours truly will be teaching a free class on Rhododendrons and Azaleas at 10am as well. I encourage all plant lovers to come and join us for a day of fun and appreciation of these wonderfully useful landscape shrubs.
Gaze upon the glory of Rhododendrons this spring and consider adding some fresh ones into your landscape mix. A visit to the local garden center this time of year is key, as I am sure there are a few that will catch your eye. Speak with a Certified Professional Horticulturist about all things Rhododendron and allow them to help you select the right one(s) for your specific garden locations. It amazes me that some local gardeners don’t appreciate the simple beauty of Rhododendrons, and it is equally surprising how much visitors and newcomers to our region are captivated by them. Sometimes those things that are perhaps common to some of us should still hold special places in our gardening hearts.
Remember, leaves up and roots down…
