Louis Raymond experiments in his own gardens like

a mad scientist, searching out plants that most people have

never seen before & figuring out how to make them perform.- The Boston Globe

…Louis Raymond ensures that trees can grow in Brooklyn…

or just about any other place where concrete consumes

the dirt and skyscrapers shield the sunshine.- USA Today


NEW Trips to Take!

Myrtle's easy when the conditions are right.


NEW Plants to Try!

Louis tries to capture the exact words to describe the fleeting but deep pleasures to be found in these Summer-into-Autumn incredibles.


New Gardening to Do!

Allergic to bees? You can still have an exciting garden, full of flowers and color and wildlife.


Plant Profiles

Perennial Trumpet Spurflower



Tiny blue-lavender flowers just barely restrained from heading right out into space by their attachment to delicate stems:  What a strange charm spurflowers bring to Fall.  In profile, the flowers have a smile on their face, like minute but happy mice about to take flight.


Rabdosia longiflora is a tall but airy perennial.  The foliage is non-descript, and so by October the slender and wide-branching flowering stalks at the tips of the stems catch you by surprise:  In foliage and stem alone, this hadn't been a perennial for a second glance May through September.




The bloom stalks catch amid their fellows, helping concentrate the floral display.




Only by luck had I planted the variegated daphne, 'Carol Mackie', to one side, so the Rabdosia stems on that side can lean out atop it to show me their flowers all the more forward in the bed.





Here's how to grow this Fall-blooming beauty:


Latin Name

Rabdosia longiflora

Common Name

Perennial Trumpet Spurflower


Lamiaceae, the Mint family.

What kind of plant is it?

Herbaceous perennial.


Zones 6 - 8


Clumping with many upright stems that spread outward as the season progresses.

Rate of Growth


Size in ten years

A clump a foot wide at the base and stems to four feet tall leaning outward for an overall width of three to five feet.


Stems and leaves: open and (frankly) sprawling unless supported.  The top quarter or third of the stems are given over to the small and, indeed, long (comparatively) and narrow flowers, which can be in the hundreds but are, nonetheless, still widely spaced on wire-thin little stems, for a charming feel of levitating confetti.


Grown for

the flowers:  horizontally-held inch-long tubes only 3/8 of an inch wide, numerous but on such long stems that they're still widely spaced.  A pair of rounded vertical petal lobes at the front of the tube combine with a projecting lower lobe to create an excellent mouse-face, at least in profile.


The lateness of bloom:  October here in Rhode Island.


Its rarity: Rabdosia are still pets of garden sophisticates, not real merit-badge material for the wider gardening public.  Admittedly, you don't accrue "cool foliage" points with Rabdosia that you get for growing, say, Syneilesis, Glaucidium, or Napaea.  But by the time Rabdosia is in bloom in October all of those are long past prime and even dormant.

Flowering season

Early Fall: October here in Rhode Island.


Reasonable to rich soil; a bit of shade is just fine, as well as a weekly deep watering if the weather has turned to drought.


How to handle it

The only thing Rabdosia needs beyond the cutting down of last year's stems in early Spring before new growth starts is a bit of support as it grows in the warm months.


If it's growing amid sturdy neighbors, just let it burgeon and sprawl at will.  Such a literally "supporting cast" might include low and dense shrubs or perennials that keep their visual integrity through the Fall; Rabdosia won't hide a thing, either in leaf or foliage, so avoid partners that by October have tossed in the towel for the season.  Perhaps, then, at the front a couple of low, dark, and mounding evergreens:  Boxleaf honeysuckle, Japanese holly, box, or rhododendrons.  At the side and back, higher mounders so the Rabdosia stems can lean against the parapet, so to speak, and watch the party.  Big leaves would be a good contrast, too:  Mounding large-leaved rhododendrons, say, or huge hostas.


I haven't followed any of this advice: All but one of the companion plants for my Rabdosia either go dormant and so provide nothing but bare space, or are themselves also clumpers whose stems arch out, and so conflict with those of the Rabdosia.  By accident alone did I plant nearby the variegated daphne, 'Carol Mackie', so the few Rabdosia stems that find their way towards it have the security of an easy resting place.  Do what I say, then, not as I do.


You could also pinch the stems once, in early June, and again in early August, which would result in shorter and branchier stems that would, one hopes, be less interested in sprawling even as they also provide a more concentrated show of flowers.  In 2012, I myself will try to do as I say, too.


With the exception of needing either a little pinching or a little support, this is a carefree perennial.


There are, as yet, only a few flavors of Rabdosia, so you can grow them all.  R. longiflora 'Tube Socks' is a white-flowered form; I'm hoping that mine will be mature enough to bloom next year.  R. trichocarpa has shorter as well as darker flowers than R. longiflora


On-line and, very occasionally, at destination nurseries.


By division in Spring, as well as cuttings in Summer.  

Native habitat

Rabdosia is native to Japan.

FacebookTwitterRSS Feed

Stay in touch!


Sign up for twice-monthly eNews, plus notification of new posts:


* indicates required