Rhododendron Research
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heyrhododendron.bsky.social
Rhododendron Research
@heyrhododendron.bsky.social
550 followers 590 following 380 posts
Research group investigating physiology, ecology, evolutionary biology and conservation of genus Rhododendron. Sharing research, gardens, plant exploration, art, culture, events, anything and everything Rhododendron
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heyrhododendron.bsky.social
Rhododendron coin!
From Nepal, 1972
A photo diagram describing a coin. The right side of the diagram shows the reverse side of the coin with a flowering truss of an elepidote Rhododendron. Nepalese writing surrounds the rhododendron. There is a smaller image of the front of the coin on the top left, writing encircles a faded graphic that may be a crown, with a crescent moon on the top left and a sun on the top right. In the bottom left of the diagram, text reads, “Nepal 1 Paisa 2029(1972) Aluminum 16.75mm 3,036,000 Engraver unknown 2028-2036(1971-1979)”
November 18, 2025 at 11:14 AM
heyrhododendron.bsky.social
🍁Fantastic Fall Color Physiology🍁

You really can’t beat lepidote rhododendrons for fall color

The plants pictured are still small but two stunning color variants here,
grown from wild collected seed

Rhododendron dauricum (E Siberia, Mongolia, N China, Japan)

Rhododendron minus (SE US)

🌿🍁🍂🌱🧪🪴
A branch of Rhododendron dauricum, with bright pink, yellow and red leaves on the bottom of the branch and dark greenish purple leaves on the top of the branch. Behind the Rododendron, you can see a wooden fence and there are other plants with different fall colors, green, gold, and red. A close-up of Rhododendron Doraku branch showing the different leaf colors in the fall. The lower leaves are pink, red, and yellow, and the upper leaves are dark green and purple. The upper leaves will be retained through the winter while the lower ones will be lost in fall. Behind the Rhododendron, there are other plants, with different fall colors green, gold, and red A small rhododendron minus plant among fallen leaves. The fallen leaves are yellow and brown. The Rhododendron leaves are dark purpleish green on the top of the branch and cherry red on the bottom of the branch. A close-up of a branch of Rhododendron minus from graveyard fields, North Carolina the lower leaves are cherry, red and yellow, and the upper leaves are purple. The lower leaves will be lost during the winter. Behind the road at dendron, you can see fall colors of a hosta plant, which is yellow and fallen leaves, which are brown.
November 4, 2025 at 2:31 PM
heyrhododendron.bsky.social
Indulged in a bit of leaf flipping yesterday

W/world class breeder Joe Bruso

breeding targets include
hardiness zone 4
leaf longevity for densely packed branches
AANNDD
My personal fav…
TOMENTUM
Aka a dense mat of hairs on the abaxial leaf surface

Details in the alt text!

🌐🌍🍁🧪
#plantbreeding
Joe flipping over a leaf of his hybrid cinnamon bears to display the nice tomentum. The plant is compact about 2 ft tall, with glossy green leaves about 6inches long, with a puffy soft cinnamon colored tomentum. Cross Includes R pachsanthum and some other sp I don’t recall My hand flipping over a cluster of leaves to reveal the tomentum. I flipped over every leaf I saw, this one had what they call a fawn-colored tomentum. It also has a nice fungible indumentum on top, which is a coating of loosely adheared white trichomes (hairs) while slowly slough off the leaves as time goes by revealing a glossy leaf underneath. This plant also retains its leaves a very long time giving it a very dense bushy habit. Joe said his ideal plant would have tomentum, indumentum, cold hardiness, nice shape without pruning and glossy leaves…flowers are generally not the target of selection My hand flipping over a leaf revealing a light fawn colored tomentum. This plant had more rigid leaves and really well developed indumentum Breeder Joe Bruso. A man with short grey hair and light skin Standing in a lush forest with Rhododendron and tall trees in the background, he wears a grey ball cap, black windbreaker and tan pants, he leans down to flip over a branch on one of his hybrids to reveal the tomentose underside
November 3, 2025 at 12:44 PM
heyrhododendron.bsky.social
Happy Halloween 🎃
from your friendly neighborhood
Bog Witch 🧙

Bogs are key habitat for
Rhododendron tomentosum
a Taiga species w/circumpolar distribution

Bog Witches are fantastic herbalists
they seek this species
for its powerful magical properties described here
pubmed.ncbi.nlm.nih.gov/23352748/
A witch standing in a golden field of dying grass and flowers next to a colorful maple tree with red gold and green leaves. the witch is wearing a lavender witches hat. She has green skin and dark blue hair. Her clothes are colorful and ragged. purple green, blood red, blue and dark green. she’s carrying a basket for collecting her witchy bog treats, and she’s carrying a magical broom with which she is trying to sweep up a pumpkin she has found. She has a look of witchy delight on her face being so pleased with her find of this nice pumpkin on her way to a far away bog find some Rhododendron tomentosum, a powerful herbal medicine also know as Labrador tea. Rhododendron tomentosum flowers. The flowers are small and white, and there are many flowers on the branch. They form a little puff ball. The flowers have five petals and very long stigma and stamen that stick out very far away from the flower. The leaves are few and small and thin They are strap shaped.
October 31, 2025 at 5:28 PM
heyrhododendron.bsky.social
This one flower bud on my Rhododendron atlanticum is…

🚨EXTRA FANCY🚨

It’s on a very tall branch that I often see on azaleas, I call them the “Superman arm” cuz they kind of punch up 😹

Anybody have a guess “why”? This bud is so different?

my guess - Superman arm has apical dominance hormones
Rhododendron atlanticum “extra fancy” bud. The bud has a cluster of flowers inside it with lots of extra green appendages on the outside. There are none of the bud scales with red tint visible, which you would see in a normal bud. Wide shot of the “Superman arm” branch that has the strange flower buds on it. Oh, and good morning sunbeam! Normal looking flower buds on the same rhododendron plant. The normal flower buds are distinct. They have red scales.
September 26, 2025 at 12:05 PM
heyrhododendron.bsky.social
Fantastic Fall color is, IMHO, one of the most under appreciated aspects of Rhododendron!

With fall colors that are just as pretty as their blooms, showing off on the greenhouse today is
Rhododendron pilosum AKA Minibush

Native to Northeast US, including Pennsylvania and Ohio
#bloomscrolling
Red and green leaves of Rhododendron pilosum Colorful rhododendron pilosum with purple, red and green leaves
September 17, 2025 at 2:20 PM
heyrhododendron.bsky.social
Oh Hai! I made Mr and Mrs Bacon and their little baby Eggbert
Felt food with happy faces! in the back row on the left is Mr. Bacon. He is sporting a blue tie and a slightly surprised look on his face (parenthood is surprising!) On the right is Mrs. Bacon. She has a pink bow and a very satisfied look with cute little eyelashes. In front is baby Eggbert, a yellow yolk face and cute pink cheeks, so proud and satisfied to be the child of the delightful Mr. and Mrs. Bacon.
September 17, 2025 at 11:03 AM
heyrhododendron.bsky.social
I still have an old mini black and white version of this I printed out from the internet like 10 years ago, I love it so much! What a lovely gift!
A very small stack of tiny papers on a desk. The papers are labeled “Continental Drift, Christopher R Scotese PALEOMAP Project. The papers are a bit stained and yellow and held together with a small black binder clip
September 8, 2025 at 1:37 PM
heyrhododendron.bsky.social
Fun day doing thermal imaging of Rhododendron minus leaves

Leaf temperature data extracted from these photos will be used to understand drought responses of R minus plants, and how that might differ for plants from Alabama, Georgia and North Carolina
A purple leaf against an orange background the bottom of the photo shows information about the photo settings. T cam 32.7°C emissivity 98 gain high, plus the date and time. the right side of the photo shows the temperature scale that goes from purple (cold) through orange and yellow (hot). A purple and orange leaf against a yellow background the temperature of the leaf was measured to be 25.7°C in the square region in the middle of the leaf An orange leaf against a yellow background in this photo the leaf was measured to be 30.6°C
August 12, 2025 at 12:14 AM
heyrhododendron.bsky.social
6/6
Congratulations to Riley Carver-Longley on her fantastic poster “marker, assisted selection for long lasting Corolla (Misome-sho) trait in hybrid Evergreen azaleas”
🧪🌿
Riley Carver-Longley with her poster “marker, assisted selection for long lasting Corolla (Misome-sho) trait in hybrid Evergreen azaleas”
August 5, 2025 at 9:52 PM
heyrhododendron.bsky.social
5/6
Congratulations to Mallory Ellefsen for a fantastic poster “exploring the evolution of Rhododendron section Pentanthera (Deciduous Azaleas)”
🧪🌿
Mallory Ellefsen with her poster “exploring the evolution of Rhododendron section Pentanthera (Deciduous Azaleas)”
August 5, 2025 at 9:52 PM
heyrhododendron.bsky.social
4/6
Congratulations to high school student
Shambhavi Sajeev for a great poster and definitely winning the prize for best title 🏆

“Hot leaves, cool blooms, exploring thermal tolerance and floral traits in Rhododendron species”
🧪🌿
Shambhavi Sajeev with her poster “hot leaves, cool blooms, exploring thermal tolerance and floral traits in Rhododendron species”
August 5, 2025 at 9:52 PM
heyrhododendron.bsky.social
3/6
Big congratulations to High school student Elizabeth Ferro on her great poster “ A preliminary test of the effects of drought on plant function”
🧪🌿
Elizabeth Farrow with her poster, a preliminary test of the effects of drought on plant function
August 5, 2025 at 9:52 PM
heyrhododendron.bsky.social
2/6
Congratulations to Nick Dedic on his excellent poster “Evaluating floral characteristics across 13 species of Rhododendron”
🧪🌿
Nick Dedic with his poster “Evaluating floral characteristics across 13 species of Rhododendron”
August 5, 2025 at 9:52 PM
heyrhododendron.bsky.social
Great day for rhododendron at
Holden Forests & Gardens
SEARCH Symposium
Six, count ‘em, Six undergraduate & high school intern Rhododendron posters!

🧵
1/6
First up, Congrats to Alex Speyer on their poster “preliminary test of soil, moisture, and atmosphere humidity on an evergreen azalea hybrid”🧪🌿
Alex Speyer with their poster Preliminary test of soil, moisture, and atmosphere humidity on an Evergreen Azalea hybrid.
August 5, 2025 at 9:52 PM
heyrhododendron.bsky.social
A stellar lab group this year, I’m tired and I need a nap because everyone was SOOO GOOD it was hard keeping up with y’all!!

BIG Thanks to the 3 senior students for being a great mentorship support system, with your help we got a lot of work done & made it a great summer for the new folks, go team!
Medeiros lab, summer 2025! front row left to right: Alex Speyer (undergrad intern), Juliana Medeiros (PI), Dylann Nakaji-Conley (Research specialist). back row left to right: Catalina of Valderrama (PostMasters Intern), Elizabeth Farro (High school), Shambhavi Sajeev (high school), Miranda Shetzer (PhD candidate) and Nick Dedic (undergraduate intern)
August 5, 2025 at 9:31 PM
heyrhododendron.bsky.social
Blooming now in the greenhouse

Rhododendron oldhamii
This evergreen azalea species has both spring and late summer blooms, nice bright red flowers with a hot pink flare give a little spice to the garden and with very fuzzy leaves, it seems to be fairly resistant to lacebugs

Native to Taiwan
Red azalea flowers with a pink flare Closeup of red azalea flowers with long stamens sticking out
August 1, 2025 at 3:06 PM
heyrhododendron.bsky.social
Rhododendron Mmmmmmakinoi
Double trouble, from top to bottom
In-du-ment-YUM!
New growth on Rhododendron makinoi. The leaves are very thin and finger like there are many of them coming out of the bud. They are covered in a fuzzy indumentum, which is a creamy white dense covering of hairs on the leaf surface. The white indumentum on the upper leaf surface is only temporary, protecting the growing leaves. as the leaves grow this will slough off, revealing very waxy, shiney mature leaf surface The backside of Rhododendron makinoi leaves have a fawn indumentum. This indumentum remains on the leaf permanently and darkens with age. The leaves of this plant can live for up to 8 years!!
July 3, 2025 at 10:58 AM
heyrhododendron.bsky.social
Fun times at the Evolution meeting #Evol2025 in Athens Georgia this past week, Rhododendron was definitely representing!

Extra special Shout Out to this lovely Rhododendron prunifolium @vkoelling.bsky.social and I came across during the super social at the State Botanical Garden 🪴
A photo of two people in front of a rodent engine, prune folium. The plant is about the height of one person it has red flowers small leaves. One of the people is wearing a rainbow, unicorn jumpsuit and a yellow bandanna with blue hair. The other person is sitting on a scooter, wearing a blue shirt and a brown skirt and black boots holding a yellow purse
June 27, 2025 at 1:03 AM
heyrhododendron.bsky.social
Rhododendron prunifolium

Native to Alabama and Georgia
This late blooming, red flowered
species is actually very cold hardy and makes a great choice to extend the Azalea blooms season in your garden
A red flower Rhododendron prunifolium. Three red flowers in the center of green leaves the flowers have five petals and our star shaped the flowers have that are extremely long and extending almost the length of the flower away from the plant. A larger view of Rhododendron, prunifolium showing that the leaves form a smooth canopy with the red flowers displayed on the surface of the leaf canopy
June 25, 2025 at 10:46 AM
heyrhododendron.bsky.social
Amazing poster and great project by Isabella Soto #Evol2025

“Development of genetic tools for the study of evolution in Southern Azaleas”

The first use of whole genome resequencine for varant identification in Rhododendron prunifolium

Supervisors @mrmckain.bsky.social
@vkoelling.bsky.social
A young woman with blonde hair and a yellow shirt wearing a conference name tag stands next to a scientific poster. The poster shows data from my study of rhododendron
June 24, 2025 at 6:38 PM
heyrhododendron.bsky.social
So pleased to snag the LAST ONE
of these amazing bandanas celebrating the 150th anniversary
of the International Journal of Plant Sciences at the Evolution
meeting in Athens GA🤩🥰🤓
@ijpsjournal.bsky.social
@sse-evolution.bsky.social
@asn-amnat.bsky.social
@uchicagopress.bsky.social
#Evol2025
A yellow bandanna with green printing. in the center of the bandanna there is a circle with the words “international Journal of plant sciences, celebrating 150 years 1874 to 2025”. There are green ginkgo leaves decorating the circle. around the circle is a copy of the first ever paper published in the international journal of plant sciences, formerly known as the botanical gazette
June 23, 2025 at 3:26 PM
heyrhododendron.bsky.social
Somehow we forgot to get predawn photos but it was a great day and so pleased with our project team for all their hard work planning, great work executing this challenging sampling campaign, woohoo teamwork!
Cupcakes in a tray, intern Nick made these amazing cupcakes for our predawn sampling day, which was also his birthday, they have coral colored Rhododendron flowers piped onto them in frosting, and on each cupcake is placed a yellow flag with a sample number like “ML40”, these look just like the flags we used to mark the location and plant id for our study The crew out in the garden after the sampling was all done, in order of appearance in the front on the left, we have intern Alex on the right front we have Dylann, who was the leader of the study and coordinated all of the predawn and midday logistics and led one of the sample teams. in the back on the left we have Bronwyn who took time out of her busy day educating high school students to work with us in our sample collection campaign, next is intern Nick who led the second team around the garden to find the samples. Third in the back is Miranda graduate student who donated her time to help Dylann‘s project and then last on the right in the back is me leader of the lab and very proud of these great staff and students who I get to work with. A woman in a stand of rhododendron. the leaves are all different shapes and sizes and surround her from her waist up to high above her head. She’s looking at a rhododendron that has an orange flag and polkadot flagging tape. She’s wearing surgical gloves and she’s looking up into the plant to see which leaves to sample
June 14, 2025 at 2:49 PM
heyrhododendron.bsky.social
We had a very successful sample collection campaign

3am-1pm in the Layer Garden at Holden Arboretum

Thanks to all the hard work of our amazing staff and students!

We collect 400 leaf samples, the liquid nitrogen was really sizzling!

Plus the food was delicious and the company was delightful!!
June 14, 2025 at 2:38 PM
heyrhododendron.bsky.social
Big day tomorrow!

We’ll be out in the gardens at 3am 💤

Predawn sampling for anthocyanin and carotenoid pigments for 33 Rhododendron species 🌺

This is about half of what we plan to collect, having fun poking holes in all the tubes so they don’t explode in the liquid nitrogen 🤯
Racks of test tubes with orange lids for leaf samples. The lids are already labeled with black sharpie numbering. There are 2 1/2 racks of tubes, but we have about six racks to fill tomorrow between predawn and midday sampling
June 13, 2025 at 12:04 AM