Those of us of an advanced age remember the old, but ubiquitous 1950s/1960s television commercials from the late John Cameron Swayze, extolling the toughness of Timex watches. I have flashbacks to that tagline every time I look at our plants of Rhododendron ‘Elizabeth Ard’ (sold as Southgate Grace). Through the years, I’ve killed far more evergreen rhododendrons than I’d care to admit. They simply aren’t tolerant of wet, hot, humid summers.
Several years ago, I was lucky to share the stage with rhododendron breeder, Dr. John Thornton of Franklinton, Louisiana. Although I wasn’t really paying attention at first, knowing that we couldn’t grow rhodies, my ears perked up, when he mentioned that he grew his plants in Louisiana wet clay. John had learned a rhododendron breeding secret that using the Asian Rhododendron hyperythrum in the parentage would created heat and humidity tolerant hybrids. As John aged out, much of his breeding lines were taken over by Buddy Lee, who pioneered the Encore azaleas. Below is our 2017 planting of Rhododendron ‘Elizabeth Ard’, which is now 4′ tall x 8′ wide.
Have you guys had success with any other varieties other than the Southgate series of Rhododendrons? I’m in Texas and the Southgate series has done well so far, but I’m trying to see what other varieties I can try here.
The heat tolerant and disease resistant Rhododendron variety Royal Resilience from Garden Treasures Nursery as mentioned in the post below performs well in zone 8a NC. We have alternating periods of summer drought, long soaking rains, clay soils, 100 deg summers and the occasional single digit winter. So far, so good.
Rhododendron catawbiense 'Royal Resilience' PP 33702- EXCLUSIVE NEW RELEASE, GARDEN TREASURES INTRODUCTION
What about Rhododendron ‘Charles Loomis’? It’s a hybrid between Rhododendron ‘Roseum’ x R. hyperythrum. (Thanks for tip on RR)
Rhododendron ‘Charles Loomis’ has done well here, although we need to move our old plant to a sunnier location.
Yes, we have had good luck with all of the Southgate series of Rhododendron.
Thank you Tony for your daily emails. As a novice gardener, I read through them religiously and have begun to file them for different parts of my garden. I was particularly glad to see today’s newsletter. My husband and I are from New York and Maryland — rhododendrons were among our favorite plants and we were disappointed when we didn’t see any in the Raleigh area, telling us that the environment just wasn’t appropriate. Will you be making the Elizabeth Ard available through your nursery? We grew them as shade plants in Maryland; is that the case for the Elizabeth Ard in the Raleigh area. Maybe Buddy Lee can come up with an Encore Elizabeth Ard so we can have those beauties in the fall, as well. Thank you!
The Southgate series should be available at most area garden centers. We do our best to shy away from woodies, since the production regimen is quite different. Our only exceptions are plants with which we have a particular association, or those which simply aren’t widely available.
We have ‘roots’ in the NC mountains in the Boone/West Jefferson area, and as a child I spent a fair amount of time rambling thru rhododendron brambles or thickets. Naturally I wanted to grow these broadleaf evergreens in our garden in Raleigh as a reminder of my 2nd home along the Blueridge. Rhodys thrive along our road that were planted in the late 60s or early 70’s when our climate was somewhat cooler, with colder winters, cooler nights, and fewer heatwaves. But after years of trying to establish native rhododendrons from the late 90’s to early 2020’s in our southern Wake Co. zone 7b/8 garden and watching them struggle, decline and fail I was ready to give up. So I planted some illicium f. and Daphniphyllum m. and tried one more supposed heat/humidity tolerant, disease resistant cultivar of Rhododendron catawbiense named Royal Resilience. I’ve been well-pleased with my rhody substitutes, and nicely surprised by Royal Resilience that seems to be absolutely bulletproof in our scorching high-humidity summers, and doesn’t blink during weeks of 100 deg weather as long as it receives moisture and is protected from afternoon sun. Royal Resilience was recently patented by Pat McCracken owner of Garden Treasures Nursery in Zebulon, NC after being developed and selected over 25 years. After 2 plus decades of testing I don’t think it would be premature to say Royal Resilience is one of the best kept secrets in rhododendron varieties bred for our southern climate. https://conceptplants.com/varieties/rhododendron-royal-resilience
We’ve only had our plant of Rhododendron ‘Royal Resilience’ in the garden for 1 year, but so far, it’s looking fabulous. This is a cross of Rhododendron catawbiense x minus, introduced by local plantsman, Pat McCracken. This promises to be a significant addition to the heat and humidity tolerant rhododendrons.
Any experience growing Chionoides Rhododendron in NC’s zone 8 climate? It claims to be hardy in zones 5-9. The white blooms would offer nice contrast to reds and pinks.
https://www.monrovia.com/chionoides-rhododendron.html?srsltid=AfmBOoouhJEsnRFkN8AIWz75l0nmFskeiSDdajSxIkX05BsuCz4UQqi_
We don’t, and I’m always skeptical of West Coast Zone 9 ratings, which is nothing like East Coast Zone 9. That said, it is a R. ponticum hybrid, so should be worth a try.