Garden Designers Roundtable – Underused Plant(s)

Underused plants is a totally subjective topic based only on one person’s experience.  So bear in mind that I’m the non-plant obsessed designer of the group!

I have visited many, many gardens and I’ve only seen this plant in three or four private gardens even though almost every arboretum and botanical garden I have visited has one.  So, in my experience, Heptacodium miconioides or Seven Son Flower is an underused large shrub/small tree if there ever was one.

With a climbing rose in a private garden in Pennsylvania

Hardy in USDA Zones 5-9, Seven Son Flower is a truely 4 season plant that tops out at 15-20 feet and about 10 feet wide.  It’s not terribly fussy and will grow in full sun or part shade.  It does require pruning at a young age to create a graceful tree form.  The small tree in the image above has been pruned, the one in image below has not.

In bloom

Now here’s the kicker…it may only survive due to its re-introduction into horticulture in the 1980s.  The Arnold Arboretum has had one since 1905, but it was rediscovered about 30 years ago and is very rare in its native habitat in China.

Why should you have it in your garden?  It rivals Stewartia pseudocamellia with its bark’s exfoliating beauty.

Exfoliating bark
Winter Interest with texture and structure

Its vase shape makes it valuable for designing a layered planting scheme and an easy companion to woodland shade lovers.

Multi-stemmed vase shape

The bold and coarse foliage is very useful when creating textural interest.

Bold foliage

Personally, I really like the buds.

Heptacodium flower buds

When most gardens are beginning to wane, Seven Son Flower puts on a show.  It has spectacular late season, fragrant blossoms when little else is in bloom.  They start out white and as the fall progresses the calyces turn rosey as if it has a second, different color bloom cycle.  They are attractive to butterflies.  Its fall foliage is golden–although pretty unremarkable.

White Bloom
Late season color

What’s not to like?

Here are the links to the rest of the roundtable posts…enjoy–it’s a plant-a-holic’s delight!

Andrew Keys : Garden Smackdown : Boston, MA »
Carolyn Gail Choi : Sweet Home and Garden Chicago : Chicago, IL »
Christina Salwitz : Personal Garden Coach : Renton, WA »
Debbie Roberts : A Garden of Possibilities : Stamford, CT
Douglas Owens-Pike : Energyscapes : Minneapolis, MN »
Genevieve Schmidt : North Coast Gardening : Arcata, CA »
Jocelyn Chilvers : The Art Garden : Denver, CO »
Lesley Hegarty & Robert Webber : Hegarty Webber Partnership : Bristol, UK »
Pam Penick : Digging : Austin, TX »
Rebecca Sweet : Gossip In the Garden : Los Altos, CA »
Scott Hokunson : Blue Heron Landscapes : Granby, CT »
Tara Dillard : Vanishing Threshold: Garden Life Home : Atlanta, GA »

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21 thoughts on “Garden Designers Roundtable – Underused Plant(s)

  1. Susan, It’s too bad you were not able to join us at the tweetup on Sunday because you would have seen another beautiful Heptacodium in John’s garden/nursery. Planted at the edge of the porch and pruned perfectly to accent the house and the garden, John was raving about how garden-worthy it is but bemoaning why it is rarely used. Love the photo of the pink calyces, it really is a unique tree.

    Everytime I go to my local arboretum in Winter it just draws me in. It’s a fab plant.–s

  2. I posted a picture from that Sunday visit today – it was the best heptacodium specimen I’ve seen!

    Scott has been teasing me with pix of that all week since he knew what my topic was! There’s several around here–all incredibly beautiful. Wish I could have joined you on Sunday!–s

  3. Great photos, Susan. I’ve never seen such a large specimen in my area, although it is part of the Plant Select program – which means it has been “vetted” for use in the Rocky Mountain West and high plains. Thanks for the reminder about this multi-season stunner.

    I didn’t know about ‘vetted’ plants. What is the criteria?–s

  4. I would even venture that it’s better than Stewartia in terms of bark! There’s one planted by our local public library that looks almost completely white in winter. Excellent choice! Whenever you make it up here, we’ll go to Bedrock Gardens (, where Jill Nooney has a whole row of them backing a really dramatic seating area…

    There you go, tempting me for another road trip…would love to see a ‘hedge’ of these…–s

  5. Great post, Susan. We both put Stewartia psuedocamilla on our list of underutilized plants. The Seven Sons shrub is definitely not used enough either.

    I have a soft spot for bark textures. Stewartia is certainly one of the best.–s

  6. Susan: I will see if we can get that plant here. Seems like a winner from all sides. great to see so many views of it in all seasons.

    Are you Zone 5? Why did I think you were colder than that…anyway give it a whirl and see if you like it. Plants are like hair–you either go bald or it grows back!–s

  7. Hi Susan,
    What a nice tree. I was not familiar with it but given its attributes, I could see using it in a design. I particularly like its size….and of course the late season color. I might have to give it a try!

    There’s a beautiful one at the Frelinghuysen Arboretum in Morristown…about a 1/2 hour drive from you if you want to get up close and personal!–s

  8. All the nursery people I know where very excited about Seven Son flower when it became available in the trade about 5-7 years ago, but the last few years it seems to have disappeared. and for good reason. You seem to be infatuated with it as a older grown specimen trained into a tree form, but most of my gardening friends that have grown it in their gardens aren’t impressed. It exhibits very poor branching when young, tends to look gangly and sparse. Its floral display is less than exciting most years, and its fall color doesn’t always turn the lovely red you have pictured. I have one in my front garden and wish I had planted it in another part of the yard, as it is just wrong. Perhaps this year I will move it when the hot spell of the Summer breaks. I have had it for about 7 years and still it has yet to impress. But I have enough property to keep it so I will move it off to a less front and center position. All the pics I have seen of this plant in my friends’ gardens have all looked the same to me. Maybe it needs twenty years or so to get pretty. Meanwhile, I’d rather have a Magnolia front and center.

    ps. one attribute worth mentioning: The deer and rabbits don’t eat it…

    As with any plant–right plant, right place, right maintenance = success. As I said it’s only from personal experience and mine has been good. And you’re correct about deer–s

  9. You’re absolutely right, what is there not to like about Heptacodium miconioides? Great choice!

    See what Patrick has to say below. His experience is different from mine.–s

  10. Maybe Seven Sons likes New Jersey, Susan? Although my gardens have been in IL & TX, hardly Heptacodium terrain, I’ve known about this tree and seen photos of it thanks to dormant blogger KI at MucknMire in NJ. He spoke of it several times, calling it extremely vigorous & made me think it was pretty cool! Bet Ki would agree with your inclusion on the underused list.

    Here’s a link to one of Ki’s posts with more history:

    Annie at the Transplantable Rose

  11. Interesting point, and I wonder how many plants are underused because they have an awkward adolescence? I gaze lovingly at the sticks and sprigs I plant sometimes, because I know what they can become, and I try to help them get there. For a client, on the other hand, if nothing happens in a year or so, it’s easy to find some curvy prom queen to fill the bill instantly.

    Kind of like real teens…do you date the one with pimples and an awkward demeanor or the ‘perfect’ popular girl? I’m lucky that I have a nursery who has this plant as a well pruned container grown adolescent beauty!

  12. Perfect choice!
    And I love those buds!
    Best Wishes

    I really tried to think about what plants I love but rarely see that could be really useful…so a big thank you for saying it was a perfect choice!–s

  13. I could not have pick a better contender for under use and infrequent installation. You are spot on. This tree is a winner in all seasons if properly trained when young. I too thought of Stewartia first with the lovely flowers, but that plant is probably used more frequently. I know that I am also one that specs it because my grower has them available.

    Why thank you. I wanted to write about something unusual but still really, really useful from a garden design perspective. I’m lucky to be able to get it in a fairly large size also…–s

  14. I once had an instructor who drove his students by a particular home just to show them how unattractive the Azara tree was and why they should never plant them. I just about died. Like your Seven Sons, the Azara might look gangly when young, but give them what they need (and a little time) and they can grow up to be a beautiful, delicate small tree. You summed it up: right plant, right place = success!

    I guess everyone has their plant preferences! Plants are often like people…small pretty ones can grow up to be monsters and the ugly ducklings can turn into swans.–s

  15. I’ve never seen it before. I wonder if they have any at the area botanical gardens…

    I will tell you that I have seen it at almost every botanical garden and arboretum I’ve been too so the possibility is pretty good…-s

  16. The specimen in the Arnold makes you want to go out and plant this tree immediately, but then most of the trees in the Arnold are awe inspiring.
    I’ve never seen this tree outside of the Arnold , never mind in a California nursery.
    I wonder how it does without cold dormancy ?

    Most sources say Zone 9, but some put the limit at Zone 8 so I guess it’s a question. I have never been to the Arnold…it’s on my list!–s

  17. I was very curiously waiting to read this post after seeing the specimen at our Tweetup this weekend. I am not familiar with Heptacodium, but have heard many mentions on ‘The Underground’, so after loving what I saw in John O’Brien’s garden, I knew you’d fill in the rest of the story on this beautiful tree. I, like Laura, (and I’m sure most designers do), view most plants and spaces with their potential in mind, so would not be turned away from a gangly, unremarkable juvenile. After all we were all gangly and unremarkable at some point right?

  18. Great choice though I have to admit my heart sank with guilt as soon as I saw your lovely pictures. I killed a very small 1 gallon size cutting that a friend gave me a couple of years ago. To think what it could be now!
    Thank you for reminding me to try and track another one down. 🙂

    It shouldn’t be too hard to track one down. One that’s more than a stick too. Let me know if you have trouble and I’ll help you source it.–s

  19. SOLD! That is a lovely tree! If only I had room – and if only clients in Los Angeles had patience with a little bit of awkwardness for a bit! They want their trees big, AND evergreen, AND litter-free. How sucky is THAT?
    Thank you for introducing me to this tree – it is a stunner.

    That’s not just LA. You’ve described the two top ‘wants’ here too….evergreen, litter free and NO maintenance. Plastic? LOL!–s

  20. Love this plant. I got one at the JC Raulston Arboretum (before the Arb. gained that name). 15-20 years ago. I found it gangly, and apt to split when it grew larger. The key is careful training as you mention.

    I used to cut stems for NC’s October state fair’s flower show. The pink brachts were perfect timing. People were amazed with the plant and had never seen it before. I usually won with this one. It took a long time for me to realize how special it was to get such unusual plants from the wonderful JCRA.

    Sadly, the plant/garden I had then is gone, but several local growers have the plant now.

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