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or just about any other place where concrete consumes

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Plant Profiles

Tanaka's Stephanandra

stephanandra-tanakae-rose-overall-640

 

What a cool rose!  But that's for next June; today, the cool bush in back of it.   

 

Stephanandra tanakae is much larger than the readily-available cutleaf form, S. incisa 'Crispa'.  It's also a terrific groundcover—but needs to be cut to the ground every year or so if it's not to take over.  (See "How to handle it" below for some strategies.)

 

I'd let my colony grow on its own for years.  It had almost overwhelmed the yew to the left, and was twelve feet wide overall.  Oops.  While the best time to cut Stephanandra to the ground is always right after it flowers in early June, the second-best time is whenever you can get around it.  For me, that means December.

 

stephanandra-tanakae-december-640

 

It took time, all of it spent on my knees, even to cut away enough growth so I could reach the heart of the colony and begin the serious lopping.  Note to self:  Do this pruning once a year, not once a decade.

 

stephanandra-tanakae-after-640

 

Finally, every branch has been lopped as low to the ground as possible. 

 

stephanandra-tanakae-after-stumps-640

 

Stephanandra sprouts right from ground level—and with pleasure—so this colony will arch gracefully next Summer, instead of hogging half of its bed.

 

 

Here's how to grow this energetic groundcovering shrub:

Latin Name

Stephanandra tanakae

Common Name

Tanaka's stephanandra

Family

Rosaceae, the Rose family.

What kind of plant is it?

Deciduous shrub.

Hardiness

Zones 5 - 7.

Habit

Mounding, with many slender branches arching from the base.  Stephanandra suckers from the base and also layers where the tips of the branches touch the ground; it can form a large colony.

Rate of Growth

Fast. 

Size in ten years

Unless controlled, a colony five or six feet tall and twelve to fifteen feet across.

Texture

Lacy when in leaf Spring through mid-Fall; passably twiggy when out of leaf in Winter even if unpruned.  Appealingly twiggy in Winter when well-pruned; see "How to handle it" below. 

Grown for

its habit: Stephanandra tanakae is a very agile large-scale groundcover.  Its arching branches become so numerous, and their collective shade so dense, that it can outcompete almost anything small enough and slow-moving enough that Stephanandra can arch over it and root to the ground on the far side.  Its prowess at tip-rooting also makes Stephanandra a terrific groundcover for banks steep enough to need erosion control. 

 

its foliage: The pointed leaves are deeply veined and sharply toothed, and hang outward and downward along the arching branches with pleasing consistency.  They acquire a decent and long-lasting yellow Fall foliage color, too; by the time of my picture, in December 1, the display was almost finished.

 

its flowers: The dangling sprays of small starry white flowers are delicate and almost foamy, and are displayed gracefully atop and amid the foliage.  They're much less bulky and dense than those of widely-known S. incisa.

 

its bare twigs in Winter: The branches of a well-pruned bush—see "How to handle it" below—have warm brown bark, and the whole bush the profile of a tidy but really wide shaving brush. 

Flowering season

Late Spring:  May into June here in Rhode Island.  As shown in the lead picture, Stephanandra tanakae is still in bud when Rosa roxburghii is in full bloom. 

Color combinations

With mid-green foliage and white flowers, Stephanandra tanakae can mingle with almost any color, from yellow to red to pink to blue, from pastels to acid saturations.  

Partner Plants

Because Stephanandra tanakae is such a good groundcover—and a tall one, potentially to six feet—partner plants need to be narrow enough to pierce through the Stephanandra canopy, and tall enough to keep their heads in the sun long-term.  Evergreen partner plants are difficult unless they look good when limbed up a few feet; the Stephanandra will shade out their lower growth.  If you're blessed with a yew that's large enough and old enough that it can be limbed up, that would be ideal.  The yew's dense and dark foliage, thick trunk and limbs, and warm-cedar bark would all provide appealing contrast.  If the yew is massive enough, the lax and wide-spreading Stephandra branches could loll through the lower reaches of the yew limbs without threatening to swamp the bush outright.

 

The easiest partners, though, are species with a single trunk, or just a few major trunks, so that the lax and wide-spreading Stephanandra branches continue to arch to the ground when flowing around them.  I have a single-trunk standard of Rosa roxburghii on one side of my colony of S. tanakae, and a young Hamamelis 'Arnold Promise' at the other.  I'll limit the Hamamelis to two or three trunks.

 

Well-contrasting foliage could be small, dark, and needly, such as the large yew above, or smooth and large and lighter color.  If you are committed to annual pruning so the Stephanandra colony won't continue to enlarge, its outer branches could arch beautifully but not smotheringly over the leaves of a large hosta.  The mid-green leaves of Stephanandra have a lot of yellow in them; to my eye, yellow-leaved or variegated hostas would be more pleasing than blue-leaved. 

 

A pruning commitment would also permit survival of an evergreen groundcover, such as vinca.  Rhododendrons that mature to eight feet and taller would be another good choice.  Their large smooth leaves would provide good contrast, and they could be limbed up as small trees, so would be safe from getting swamped by the high surf of Stephanandra beneath them.

 

Bulbs that complete their flowered and foliage cycle by May are another potential partner, because they're dormant by the time the bush's arching canopy of dense shade is formed.  Snowdrops, Winter aconite, dwarf dafs, and crocuses could all succeed.

Where to use it in your garden

Even well-pruned individuals—see "How to handle it" below—are liable to be six feet across, so Stephanandra tanakae is easiest to use where it has enough space.  The leaves and flowers are enjoyable at close-range so, while the species' works well as a background filler shrub, it's even better if you can site it on the pathward side of its partner plants.  Growth on well-pruned plants can be so regular that Stephanandra tanakae could be the tidy-yet-relaxed groundcover to formal groves of larger standards or small trees.  This simple en masse usage has the addition advantage of emphasizing the bush's Winter twigs, which show up all the better when there's a horde of hundreds or even thousands.

Culture

Full sun to part shade.  Any reasonable soil that doesn't become too dry in the Summer.

How to handle it:  The Basics

If you have the room and your Winter isn't testing the limits of the bush's hardiness, Stephanandra tanakae needs no care beyond the initial planting and watering.  But it's more often the case that you'll want to limit the colony's extent.  The arching branches, which more often then not will have rooted at their tips, make pruning an old and therefore large colony awkward.  To reach the center even with loppers, let alone hand-pruners, you'll need first to succeed at fighting your way under the canopy on your knees. 

 

Instead, prune regularly so that the colony's spread hasn't become so wide as to make access to the base of the branches difficult.  This means pruning yearly or, more casually, every other year.  Prune right after flowering, so there's the maximum amount of warm weather for new growth to lengthen as well as form the flowerbuds that will make the floral display the next Spring. 

 

Prune all the branches down to the ground or as close thereto as you can stand; this is known as coppicing.  The stubs that you leave behind aren't attractive, and Stephanandra is used to sending up new shoots directly from ground level, anyway. 

 

If at all possible, refrain from tip-pruning, which only degrades the lovely arching of the branches.  If your climate, or that particular Winter, has tested the bush's hardiness, and some die-back has become evident as the rest of the bush leafs out, prune those tip-dead branches all the way to the ground as soon as you can get to it.  Yes, this removes them as well as their flowers, but you'll be encouraging new shoots for next season, as well as controlling the bush's overall size with style.  If your Winters are routinely severe enough to produce die-back, you could (I suppose) just coppice the bush each Spring, before flowering.  You'd preclude flowering, but your Spring coppice would encourage the bush's intriguing foliage and graceful form even as it also ensures control of overall size.

How to handle it: Another option—or two?

If you have the patience, as well as particularly long-nosed and sharp hand pruners, you could thin the bush instead of coppicing it.  Thin only the older branches, which will preserve the bush's size through the growing season even as it restrains it.  But because this would take place after flowering in June, I can't imagine having the time.  June by definition, is a month of garden frenzy, with a to-do list that, at best, is never less than unmanageable.  If you coppice, the pruning might take ten minutes; if you thin, a half hour.

Quirks or special cases

Stephanandra tanakae can be trained into a graceful weeping standard.  Early in Spring after you've let the bush establish for two or three years, select the largest branch that can conveniently be staked to vertical, and do so.  Then cut away all the other branches in the colony at ground level.  With the support of the stake, the staked branch will grow longer than normal, to arch out and down from the top. 

 

Yes, there will always be the inevitable sprouts from the base.  You could prune these away, which takes a certain diligence, true.  Or you could prune them to the ground in early Spring, so they form a shorter and non-blooming base to the weeping canopy above them.  In this latter case, grow the staked trunk of the Stephanandra standard to five feet or higher, if possible, so its arching branches are less likely to meet up with those from the base.   

 

Stephanandra standards will need permanent support, so it's best to stake with metal, not wood.  I use sections of rebar, which are economical, nearly immortal, easy to cut to length, and visually discrete.  Pound as deeply into the ground as you can; two feet isn't excessive at all, and three is better.  A rebar stake that needs to be five feet high, then, will be eight feet long.

Downsides

Deer will chew the twigs.  There can be tip die-back after a severe Winter, but the bush is easy to prune back, and it recovers quickly.

Variants

S. incisa is just a bit smaller, and its leaves are strongly lobed ("incised").  S. incisa 'Crispa' is notably smaller—only to two or three feet, even without pruning—and its leaves are more deeply notched and ruffled-edged still.   It's a handsome groundcover.    

Availability

On-line.

Propagation

Stephanandra propagates easily from cuttings.

Native habitat

Stephanandra tanakae is native to Japan; the species' name honors the Japanese botanist Yoshio Tanaka.

 
 
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