Abies balsamea 'Nana'

Abies balsamea 'Nana'

Tuesday, June 3, 2014

In which a Rhododendron addict overdoses, Part II: Roxieanum (the Name on Everyone's Lips)

Upon exiting the conservatory I finally was able to take more careful notice of the plantings around the building. These gardens are quite new, with some plants that must have been planted within only the last year or so. Many of them are growing in quite exposed conditions, without the high canopy of conifers that most of the garden is covered by, though most still receive some protection in the middle of the day or afternoon.

Note: Again, I've abbreviated Rhododendron scientific names as "R" to save typing. Names of non-rhododendrons are spelled out completely. A couple of rhododendron terms that may or may not be familiar: indumentum - a coating of hairs on the undersides of the leaves; tomentum - a coating of hairs on the top surface of the leaves. Just remember, indumentum under and tomentum on top.

And with that quick lesson, away we go!
One of the most striking (hardy) plants for me was this little Rproteoides. Yes, that fuzzy tomentum really was that vibrant rusty orange!  
A little over a foot high and half again as wide, this tidy little rhody would fit wonderfully in a partially shaded rock garden or a small garden where space must be reserved for truly worthy plants. The flowers are attractive bells of white to cream with a faint pink blush and darker pink midlines along the lobes. This species has been used in some very interesting crosses with species including R. macabeanum and R. pronum, producing exceptional foliage plants.

R. 'Ever Red', a new hybrid from Glendoick with exceptionally dark maroon foliage and dark wine red flowers. The RSF was the first source in the U.S. for this exciting new hybrid. It is also now available at Lael's Moon Garden and probably other nurseries and garden centers around the PNW.
 The RSBG has a large grouping of diverse forms of Rroxieanum. I was very excited to find my Rroxieanum var. oreonastes at Downs' Rhododendrons recently and so was interested to see what the other forms looked like. I have to say I love them all.

Rroxieanum var. cucullatum may be my favorite form of this species. The mature foliage is glossy, almost metallic, dark green with a thick, rich brown indumentum underneath. The new growth is an absolute marvel. It seems almost opalescent, like mother of pearl, with the subtle shading of colors and faint sheen under a light coating of tomentum. After seeing this, I took a much closer look at my Rroxieanum var. oreonastes and saw some of the same metallic sheen, though it's a bit harder to detect because the foliage is so narrow.

Another form of Rroxieanum with narrower leaves. This shot was taken from the more shaded side of the plant, as it grows at the base of a tree and is reaching away somewhat towards the light.

I couldn't reach or find a label for this plant, but I'm pretty sure it is another form of Rroxieanum (or another member of Subsection Taliensia, of which Rroxieanum is a member). This form lacks tomentum on the new growth, allowing the tops of the leaves to shine clearly. 

I love the contrast of the lighter new growth, with its pearly sea-green color, against the darker green of the older leaves. The dark indumentum peaking through here and there adds another layer of depth.

A narrow leaf form, probably Rroxieanum var. oreonastes. These plants were 7-8 feet tall and at least 9 feet wide, so although it may be slow growing, this species can eventually become a large shrub. But look at that texture! 

Stepping back a bit. This texture is hard to match or duplicate with any other hardy plant for the PNW.

Another wide-leaf form. Love the contrast with the light new growth and dark indumentum!

The name on everyone's lips should be "Roxie!"


 As you can probably tell by now, I'm rather enamored of R. roxieanum and could probably have spent quite a bit longer just examining the different forms in greater detail, but I had only begun to explore the garden. There's much, much more to see!

An azalea hangs over a field of daylilies, centaurea, and Siberian irises.

A rhododendron I couldn't see the tag for, but had to include for the beautiful golden new growth.

One of the later-blooming species, R. dichroanthum ssp. siphocalyx. With colors that rival the tropical vireyas in vibrancy, this species has produced some fantastic hybrids.

Another I couldn't see the label for, but had to include for the thick, textured leaves with a dusting of tomentum.

I loved this Rubus species. The red hairs remind me of Gaultheria pseudonotabilis in the conservatory. Another plant I need to ask the good people at the RSBG to ID for me.

Whenever I see a mature Stewartia pseudocamellia, I have to take a picture of the bark. I dare you to resist doing the same.

I'm quickly learning to appreciate the genus Alchemilla. My favorite so far is this Alchemilla alpina. Unlike my little Alchemilla ellenbeckii, alpine lady's mantle is large enough to provide some real weed-preventing ground cover. I also love the subtle silver edge on the leaves and the smoother, more deeply cut shape of the leaves, as opposed to the more ruffled leaves of common lady's mantle. 

Now that I've seen it in "person", Alchemilla alpina is my first choice in this genus and I'll definitely be using it in the future as a ground cover in shady beds.

Rodgersia makes a nice pairing with this rhododendron, a yakushimanum type, I believe. 

Look at the new growth on R. maximum! I'm calling this the watermelon rhododendron from now on, for obvious reasons. R. maximum I think represents the typical humdrum rhododendron, plain, dull smooth green leaves and flowers that generally inspire yawns, yet even it can surprise!

At first I thought something might be wrong with it, but looking around the entire plant appeared the same, as did its neighbors. An internet search didn't turn up anything like this. I wonder if this coloration is unique to this collection of R. maximum or if simply no one has uploaded pictures of this stage of new growth to the internet. 

R. tricanthum bursts with color. Rising above them in the background is a grove of magnificent Cornus controversa, or giant dogwood. I love the tree specimens at the RSBG as much as the rhodies. 

A closer look at R. tricanthum.


O.K. it may seem like I'm tossing the word "favorite" around quite a bit, but keep in mind the genus Rhododendron includes 1000-1200 species, so I think I'm allowed to have many favorites. This one is another favorite, for obvious reasons, Rcampanulatum ssp. aeruginosum. The flowers are ok, but the real attraction of this plant is the incredibly blue new growth.

The entire plant has a blue cast to it all summer. Rain does wash a bit of the glaucous blue coating off, but not enough to diminish the effect. The mature leaves also have a gorgeous tan or light brown indementum.

Next time: This garden will stump you, in more ways than one!

19 comments:

  1. This post makes for a handy reference one when referring to Rhododendrons with interesting and unique foliage. Once again aplenty here! Love the roxieanum group, with their narrow foliage and superb form that is atypical of one usually perceives rhododendron leaves should be.

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    1. Rhododendrons deserve to be better known for their foliage! Glad you're enjoying it!

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  2. What a great collection and your post has excellent photos and accompanied text. I enjoyed every bit of it, such diversity in what many (myself included at one point) think of as a boring group of plants.

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    1. Why thank you, Loree. The RSBG really inspires me, thus it makes for pictures and good writing. I could see a Rhododendron proteoides shoe-horned into your garden. The specific epithet does mean "resembling Protea" after all.

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  3. And here I was just impressed by the flowers of the Rhododendrons. We don't see many Rhododendrons here, other than evergreen azaleas, so perhaps I can be forgiven for my ignorance. If I lived up that way, I'm sure I'd be a Rhodie addict too.

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    1. You're forgiven. I hope you can forgive me for continually rubbing rhododendrons in your face.

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  4. I wasn't looking to add Rhodies to my garden, but due to your post I'll be giving R. proteoides a consideration for its tidy habit, as well as R. dichroanthum for the amazing orange flowers. My question though is about Alchemilla alpina: does it share the spreading habits of the common lady's mantel? Were the blue poppies still in bloom when you visited the garden?

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    1. Haha! I'm spreading the rhody bug! As I haven't grown Alchemilla alpina in my own garden yet, I can't give any personal testimony. From what I've read though, it is better behaved than common lady's mantle. It does reseed a bit, but not aggressively.

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  5. Too bad these species Rhodies aren't more widely available. They're very nice. Love the Rodgersia flower and the Alchemilla foliage.

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    1. It is a shame. I prefer many of these species to the standard hybrids (though there are some hybrids that have both decent foliage and flowers).

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  6. MUST visit this place. Thanks for the introduction (both to the place and to many Rhodies new to me).

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    1. My pleasure. It's so worth visiting, not just for the rhododendrons but for the many ferns, trees, and other plant specimens.

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  7. I just stumbled across your blog so this is a very late comment, but the red-leaved Rhododendron maximum could be 'Mount Mitchell' a.k.a. 'Red Max'--you can read all about that plant's interesting history here: http://scholar.lib.vt.edu/ejournals/JARS/v48n1/v48n1-kehr.htm

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  8. Thank you - really nice pictures, I love the different foliage, I have several of that kind too. No. 15 is R. wiltonii, a very beautyful rhodo.
    Regards from Denmark

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  10. can i just add pics from the internet on arizelum x mallotum do not correlate to the look of the plant but it does tally to what I was sent from Glendoick

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  11. That plant you can't id looks very much like arizelum x mallotum. Very much resembles mine minus the orange tomentum. I've seen some pics of arizelum from glendoick which displays this characteritic

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