Bloom Watch: The Azalea Collection 2024

Bloom season for the Azalea collection is fast approaching, and Curator of the Arboretum’s National Native Azalea Collection Carson Ellis is keeping an eye on the plants as they begin to blossom. Read on for her weekly updates on what’s blooming in the garden.

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Around this time of year, the azalea collection would typically wind down for the season. As the final blooms drop and the vibrant colors of fall change fade, the collection goes quiet as it prepares for the vibrant spring bloom show. This fall, things have been different. 

The Arboretum has made tremendous progress in our recovery efforts across the property, allowing the formal garden to open to all who need a breath of nature on October 28th. Carson and I have spent these many long and confusing weeks aiding the rest of the horticulture staff in clearing key roadways and exhibits. 

When I first walked onto the property after the storm, it was hard to not feel scared of what I would see in the azalea collection, it is in the floodplain, after all. While the entrance of the Collection looks scary, with downed trees and missing trails, the garden itself is okay. It appears that most of the landscape was under 6ft of water throughout the storm, which scoured the wood chip trails and mulched bases of trees. But amazingly, the ferns and sedges that dotted the collection ground remained rooted. The azaleas have proven themselves to be a hardy riparian species, even the ones pushed by raging water remain intact, though on the ground. 

We began inventorying the azaleas a few weeks ago to assess our losses, but Carson believes that most of the azaleas that were damaged in the storm will be salvaged. Healing ourselves, and healing the azalea landscape will take time and effort.

The stormwater through Bent Creek has rearranged some of the familiar landscape, trails have moved, and the creek takes a different shape as it passes by the collection. None of these changes are detrimental, and we will spend the winter nurturing the collection back to health.

When spring arrives, the impacts of the storm will have softened and the azaleas will put on their annual bloom show. 

This year, we successfully mapped and added each azalea specimen to our digital database for health monitoring, and record keeping. Our seed collection trips have paid off and we are propagating over thirteen different species of azalea in our hoophouse to overwinter. Recovery is possible, and the azalea collection will still be here. Onto the next season, and see you at Azalea Day 2025!

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Back in March, Carson and I attended the Bog Learning Network conference and attended a lecture on daylighting. “To daylight a waterway is to restore it, returning a stream, river, or pond that had been confined to pipes and channels back to its natural flow. In the case of wetlands, daylighting often includes restorative removal of encroaching shrubs and trees. In all cases, water is brought back to sunlight” (Post by Carson from May 15th). All summer, we have continued to work on daylighting in our blog through tree removal, invasive species removal, and the opening of waterways to encourage daylight back to the water. Through our efforts, the bog has been flourishing with new species and splashes of color. 

Throughout the collection, we have been working on selective tree and shrub removal to better curate the landscape for the azaleas to thrive. It seems like some bears also wanted to get involved in landscaping, and they tore down multiple spicebush trees (Lindera benzoin) in search of food. Even though it was disappointing to see our trees torn down, it was a good reminder that sometimes nature will make decisions for us. 

Make sure to watch your step in the collection, as I have seen a couple brave box turtles taking the paths themselves, and they keep returning! Eastern box turtles tend to keep a routine and walk the same paths regularly. Did you know that box turtles have an average lifespan of 50 years? You can also determine the sex of the turtle by its eye color: males have red eyes, while females have yellow/brown eyes.

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August 24, 2024

Jewelweed, (Impatiens capensis; pictured right) is one of the more magical plants found in the Azalea Collection. Its attractive, strangely shaped orange or yellow flowers have a lovely aesthetic appeal, and it is also a piece of Appalachian Heritage. Jewelweed has been used medicinally for generations in the Appalachian Mountains by Native Americans and other folks who have grown up in these old mountains. Its sap can be used to relive the irritation of stinging nettle and poison ivy, and may even have antifungal properties. The jewelweed flower is also very unique, called cleistogamous, meaning they self pollinate! These flowers never open, and can fertilize themselves without ever coming in contact with other flower pollen. However, jewel weed pollination is aided by our bees, butterflies, and hummingbirds! I often find our ruby throated hummingbirds (the only native hummingbird to North Carolina!) flitting around the masses of jewelweed in the Azalea Collection. 

The end of august brings about the end of azalea blooms for the season, the teaching circle has our latest blooming R. prunifolium (pictured left) of the season. Typically, we could expect some of these prunifoliums to continue their flowers into early October, but due to the drought conditions in July at the beginning of their bloom cycle, the flowers seem to be disappearing quickly. Never fear, the azaleas are gearing up with new flower buds to put on a show next spring!

Recent rains have also encouraged a multitude of mushrooms to pop up around the collection. Fungus identification is not a strong suit of mine, but it is a good reminder to pay attention to the beautiful and interesting species that proliferate the Azalea Collection, even after the azaleas are finished blooming for the year.

It’s joe-pye season (Eutrochium fistulosum)! Late summer brings around the lovely purple blooms of joe-pye weed, and the air is full of pollinators. Joe-pye can be found all around TNCA, and we have a multitude of it within the bog of the Azalea Collection. If you are looking for an easy way to attract pollinators, including hummingbirds, to your home garden, consider planting joe-pye as opposed to the non-native butterfly bush. Joe-pye is a lovely pollinator attractant because it is both a food source and its hollow stems provide for nesting habitat for native bees. The R. prunifolium is pushing out its final blooms in the collection before fall settles in, so don’t hesitate to stop by to see some of the last azalea blooms of the year.

One of our final azalea blooms this year includes Rhododendron serrulatum (The Hammocksweet Azalea; pictured left). With only one specimen within our collection, it is a harder to find azalea. It just put out its first sticky white blooms this week, and it smells amazing! R. serrulatum was only recognized in 2018 as a distinct species from R. viscosm by Weakley’s Flora because of its distinct morphology, including that it can grow nearly 20ft tall, as opposed to the 3-6ft of R. viscosum. The corollas of R. serrulatum are also glabrous, or smooth, inside, and are twice the length of the flower petals.

Over in the Azalea section of the greenhouse, we are propagating baby azaleas and other species of interest to plant within the collection landscape. Tiny azaleas are quite finicky, and are very particular about the environment and propagation method. We have a variety of techniques like growing from wild-collected seed, or taking cuttings to propagate under a mist bench or inside a humidity dome. Unfortunately, a small army of Io moth caterpillars found their way into the hoophouse, and were chewing on a lovely R. prunifolium (pictured left). To remedy the situation, I took them home to raise into moths! Every day there is something new to learn, and I hope you all explore the collection and love it as much as I do.

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The end of July brings the bloom of the plumleaf azalea into full swing! The entry garden collection of Rhododendron prunifolium contains a special secret: the furthest left tree has fused petals! Rather than each bloom containing the typical 5 petal arrangement, many of these flowers have 3 or 4 petals that seem to come from the fusion of the original 5, an exciting discovery! While the trails are dotted with pink and red bursts of color, there is so much more in bloom if you look closely. Within our bog, the Sagittaria latifolia (broadleaf arrowhead) is poking its head, a personal favorite of Carson and I. The beautiful Monarda fistulosa  (bee balm!) is hiding along the entry walkway and trails. It is easy to focus on finding the summer blooms, but I believe one of the best parts of late summer is the saturation of green around us! Don’t forget to take a moment to absorb all of the colors this time of year can offer.

There are many active birds this time of year and I have taken an interest in watching a nesting cardinal in one of our azaleas, along with our pileated woodpeckers, goldfinches, and eastern wood-peewees! If you are looking for a nice place to go birding in the Azalea Collection, try the furthest back bridge near the back loop of the collection. 

This week we also had the opportunity to attend the Cullowhee Native Plant Conference at Western Carolina University. I attended a special lecture on gardening for our native pollinators, as well as lectures on native southeastern grassland restoration, and gardening for bat conservation! I find long days of lecture quite enjoyable, so a week out of the field to chat with and learn from experts, take notes, and explore the woods in Cullowhee was lovely. I highly recommend attending next year’s conference!

Photos of beebalm (Monarda clinopodia, top left) and wild potato vine (Ipomoea pandurata, middle right) within the Azalea Collection.  Photo of fused petal arrangement on R. prunifolium (bottom left). Typically, we expect azaleas to have 5 petals, but this specimen has flowers with only 3 or 4 petals

Azalea Collection trips become more difficult as the summer progresses. While it is pretty straightforward to determine what species of azalea you are looking at when it is in flower, the task becomes increasingly difficult when there are no blooms. I have found this one of the more challenging parts of my internship, learning the identification of all our native azaleas when there is no flower to look at. At this point of the summer we are on the hunt for the sweet azalea (R. arborescens; pictured left) around Toxaway Mountain and Panthertown Valley.

Toxaway Mountain revealed a variety of out of bloom azaleas, including what we believed to be R. calendulaceum, arborescens, and viscosum. I also saw a spotted towhee for the first time, as well as heard an indigo bunting singing!

Panthertown Valley had an abundance of wild lowbush blueberries (Vaccinium angustifolium), ferns, and mushrooms, especially as we walked through the wetlands. Looking to collect R. arborescens we marched onward to Schoolhouse Falls, only to stumble upon what we have dubbed “The Sugar Sand Azalea”. Sometimes you find the sweetest things when you aren’t looking too hard, here in the middle of a white sand beach was a perfectly fragrant and in bloom arborescens! Blooming around it were St. Johns Wort (Hypercium. sp), R. maximum, and R. pilosum. We also spotted 3 snake species, believed to be a Northern Watersnake, a Queen snake, and a Southeastern Crowned snake!

In the collection, the first week of July kickstarts the blooming of R. prunifolium (the Plumleaf azalea; pictured right), so keep an eye out for it on the entry bridge! You can also view the beautiful bloom of the bottlebrush buckeye (Aesculus parviflora) and the sweet smelling blooms of stewartia ovata this time of year.  

– Madison (Azalea Collection Intern)

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I write to you as the new intern of The North Carolina Arboretums’s Azalea Collection intern! I’m Madison, a recent UNC biology graduate and the newest student of azaleas! My first azalea outing was to Big Yellow Mountain Preserve, alongside members of the Azalea Society and guided by Brian Parr from The Nature Conservancy (TNC). Big Yellow is a unique ecosystem that is protected by TNC, as it is a historic high elevation (5,800ft!) grassy bald overlooking the Blue Ridge Mountains. This bald is home to rare plant communities, wind gnarled trees, and a host of Rhododendron calendulaceum (pictured right), commonly known as the flame azalea. With a permit we were able to take cuttings of some specimens to bring back to the Arboretum  in the hopes of diversifying our own selection of flames within the Azalea Collection.

Back down in the Native Azalea Collection (elevation 2000ft) you can expect to see the lovely Rhododendron viscosum, the swamp azalea, in bloom. R. viscosum is a fragrant and diverse species of azalea with a wide range across the east coast. We also recently collected a variety of viscosum, R. viscosum var montatum, which has unique characteristics such as a shorter height and that they are clonal! We hope to represent this variety in our collection soon if the cuttings take root. We are also seeing the beginning of the bloom of our swamp rose, Rosa palustris, and our native phlox (Phlox carolina)! There is no shortage of beauty and blooms to discover this time of year, whether it be your yard or the beautiful mountains (though I do recommend stopping by the Collection.)

– Madison (Azalea Collection Intern)

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In close succession to the Rhododendron calenduleceum, the Rhododendron cumberlandense and famed Gregory Bald Hybrids (pictured left) begin to bloom in the Azalea Collection. My favorite specimens are the Rhododendron cumberlandense x viscosum specimen, just a little before and to the left of first wooden bridge, and a Gregory Bald hybrid (planted at the back of the landscape, before the second wooden bridge) that we call 1992-216*B. This specimen clearly shows its hybrid heritage with big, bright, seven-petalled flowers– I love it! Each year this specimen and the Rhododendron x viscosum provide pollen to hundreds of little Andrena bees. Oligolecty (specialization by a pollinator on certain plants) is common in this genus of bees, Rhododendron cumberlandense and its hybrids certainly seem to have all of their attention while in bloom. 

Also seen around azalea flowers this time of year are fleshy galls, aptly named “azalea apples”. These unsightly green ‘fruits’ are caused by a fungus, Exobasidium vaccinii (pictured right). I see azalea galls everywhere I go and am sure that there is no stopping spores from drifting in from the surrounding forests (where Rhododendron calendulaceum and other azaleas grow naturally), but I still make an effort to control the galls within the Native Azalea Collection. This year, the Azalea Collection welcomed a new summer intern and gall-harvester extraordinaire to help with this effort: Madison McDowell (pictured left)! Madison is a recent graduate from UNC Chapel Hill where she studied biology and neuroscience. Madison has been a great help across all facets of managing the Native Azalea Collection: she has assisted on collection trips, taken on landscape maintenance tasks, cared for plants in the nursery, and is updating our plant records database. Madison will also be writing updating this blog with new posts for the rest of this season, so stay tuned!

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This winter I attended a meeting of the Bog Learning Network, BLN, and was introduced to some bog-people in-crowd jargon: “daylighting”. To daylight a waterway is to restore it, returning a stream, river, or pond that had been confined to pipes and channels back to its natural flow. In the case of wetlands, daylighting often includes restorative removal of encroaching shrubs and trees. In all cases, water is brought back to sunlight. I’ve adopted the word for all of my restoration activities in the Native Azalea Collection, including the restorative canopy management that has been returning light to sun-starved azaleas throughout the Collection landscape. 

Azaleas will surprise you with their resilience (case and point, I recently received a shipment of twelve Rhododendron prunifolium that had busted out of their box, were haphazardly re-potted by postal workers, and then were marked as “undeliverable” and left in mail limbo for nearly two weeks before I was given a note asking me pick them up at a warehouse– all but one survived the ordeal!). An azalea might persist in deep shade, putting out few flowers, growing slowly, for years. This spring we’ve had the pleasure of watching some of our azalea specimens, released from deep shade, bloom for the first time. This is especially true for our flame azaleas, Rhododendron calendulaceum (pictured left), many of which did not bloom in 2023, but have rewarded the past year’s “daylighting” efforts with a bounty of fiery flowers over the past week.  Guests often ask me what my favorite azalea is and, though I struggle to pick just one (gratefully, my work doesn’t require me to choose), I’ll often say that it is Rhododendron calendulaceum, citing the fact that they are the first azalea I ever noticed: as a kid, growing up in Asheville, the flame azaleas always bloomed for my birthday. There’s a fantastic diversity of flower size, form, and color within this species, and it can be appreciated growing throughout the Native Azalea Collection as well as growing naturally across the Arboretum’s property. 

 

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The most-asked question we get in the Native Azalea Collection is, without a doubt: “When is peak bloom?” Guests who ask me this question are guaranteed to get an answer that is much longer and more complicated than they hoped. It pains me a little bit to recommend just one day or week of the year, at the expense of the Rhododendron species and wildflowers that bloom the rest of the year! But, if I have to pick a date (as I do, when scheduling the Azalea Collection’s big event, Native Azalea Day), I pick the last week of April. Bloom times can vary from year to year, but this year we hit the nail on the head with April 27th, the date of our second-ever Native Azalea Day! 

When evaluating “peak bloom”, I think about two factors: first, the number of species blooming at once. The Azalea Collection features 16 species of Rhododendron, with the first blooming in late March, the last typically holding on into October. In mid- to late-April, we get to enjoy nearly half of these species blooming together, this is the most diversity of blooming azaleas that can be expected in the Collection throughout the year. Second, I think about the number of flowers– visiting the Azalea Collection, you might note that some of our specimens are larger and better positioned (by this I mean: are getting more sunlight) than others, these specimens put on the biggest displays. The majority of our big, extra-floriferous azaleas belong to the species Rhododendron austrinum,  Rhododendron canescens, and Rhododendron periclymenoides– all three of which overlap in bloom time around mid- to late- April! 

All that to say, Native Azalea Day 2024 was a splendid day: visitors enjoyed an abundance of flowers and new activities, including youth-oriented activity booklets designed and illustrated by local artist Stephen Brom, a DIY-cyanotype activity led by local artist Callisa Lawn, and a self-guided scavenger hunt created by our partners at the Hemlock Restoration Initiative. We’re looking forward to continuing our string of good luck with another beautiful, sunny Native Azalea Day in 2025!

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