Edgeworthias Light Up the Winter
1/14/2024 5:44 pm
Every winter, Georgia Facebook garden groups (except Georgia Perennial) are filled with repetitive posts asking what this shrub pictured above is. I'm glad people are excited by it, but I confess I wish they would scroll down a few posts to see if someone else asked moments earlier. The Metaverse has many flaws. That said, this is a shrub that merits a lot of attention.
Edgeworthia chrysantha (Paperbush) is a botanic relative of Daphnes. Like many Daphnes, Edgeworthias are winter bloomers and very fragrant. Edgeworthias also don't love soaking wet roots, but they are not as temperamental as Daphnes in this regard. A common name is "paper plant" because the inner bark is used by the Japanese to make high quality paper, including bank notes.
Edgeworthias are deciduous shrubs. The buds form in fall while the leaves are still on the plant. These will continue to grow after the leaves drop, forming tight white umbrels. In late January or early February, these umbrels will hit their maximum size and the individual flowers within will begin to open. The tubular flowers spread open slowly, showing their yellow interiors and releasing a super sweet and slightly musky fragrance. They will expand to look like little chrysanthemum heads. They will fade back to white before they drop, although the flowers can persist quite a long time.
When the flowers are done or mostly so, the elongated, three to five inch dark green leaves will begin to push out. These leaves provide a pretty and dense background until frost. The only time that Edgeworthia is not pretty is when the leaves yellow and fall off en masse. At that point, it will remind you of a compact Magnolia!
Edgeworthias don't mind cold. That said, they are not invulnerable to winter trauma. When the polar vortex dropped temps from the mid sixties to the teens in a day in winter 2023, the buds were lost (like many other winter bloomers and Hydrangea macrophyllas). If it is a very wet winter and the buds are overly wet or ice over after a rain, they can mold and disintegrate instead of opening. Still, even with some risk of losing buds once or twice in a ten-year span, it is a very worthwhile plant, quite stunning in the months when little else is.
How big Edgeworthia gets is a matter of some debate. Which Edgeworthia you have makes a big difference.
The earliest Edgeworthia import to the U.S. was Edgeworthia papyrifera, which the Atlanta Botanical Garden had in the Japanese garden. It garnered tons of compliments, but was difficult to find in the trade for years.
This Edgeworthia was closer in size and form to its Daphne relatives, rarely getting more than 3' - 4' high and wide. It had much smaller leaves than E. chrysantha too, maybe three inches maximum length. If planted in an area with poor drainage, it would up and die like a poorly planted Daphne. Still, it had a certain elegance that its currently more popular relative lacks.
The Edgeworthia currently dominating the market is E. chrysantha. It is a much bigger and hardier plant than E. papyrifera, dealing with cold better and even growing in colder zones (7b to 10b, and possibly colder per Plant Delights). According to Plant Delights, Edgeworthia chrysantha is a triploid form and Edgeworthia papyrifera is diploid, with the triploid dealing better with cold. (Conversely Missouri Botanical Garden -- incorrectly to my mind and growing experience-- posits the names probably refer to a single species. I'll side with Tony Avent on this one!)
Sources put its maximum size all over the place. Plant Delights says it can grow to 8' tall, which is definitely more accurate than Missouri Botanical Garden's 4' - 6' high (and wide) estimate in my experience. You will have to prune it to keep it that size! The outside limit may not yet be known! I gave one to a neighbor that now looks like a small tree, and is easily ten to twelve feet wide. I have a 10' wide one now. Don't let that intimidate you from having one in a smaller space. As detailed later, the stems are pliable and take pruning well.
Despite there being named E. chrysantha cultivars out there like 'Snow Cream', most are simply selections of especially attractive plants given names and vegetatively cultivated. A red flowering version E. 'Akebono' -- leaning heavily to orange-ish -- sometimes shows up on the market, but it is tremendously less floriferous. Frankly, I'd call it an expensive flop.
Planting and Care
Don't plant Edgeworthias where they will sit in water, but E. chrysantha will do fine in ordinary garden soil. Shade or even nearly full sun doesn't really phase this plant except that leaves may droop in the hot summer sun. Even in a drought year, it will just droop and maybe shed some leaves without real harm to the plant overall. (Should you find a E. papyrifera, treat it more like a Daphne and plant in some shade in very well-drained soil.) After a year to establish, I find Edgeworthias do just fine with no additional watering support.
If you plant Edgeworthia in a flat area, you can prune it up to a single main stem for an elegant vase shape. The main stem can get quite thick; I've seen them up to six inches. I have recently seen Edgeworthia standardized, much like Hydrangea 'Limelight" frequently is. They are fast growers, however, and I think a standardized one might be high maintenance to prune.
Otherwise, Edgeworthia will grow in a vase shape, more or less, with many ground suckers shooting upwards. The good news is that Edgeworthia takes pruning well, at any time of year. A chainsaw to a main stem (6" across) didn't faze one I mistakenly tried to grow as a single-stem on a slope and it has grown back well. I took the opportunity to dig it up and move it soon after to a roomier spot. Edgeworthia transplants like a dream.
Shaping or thinning is a breeze. The stems are soft and easy to cut. The one pictured below fell over, possibly trampled by a buck (but not eaten) and then further felled by near tornado velocity winds. I thought I'd lose it and it required some serious rehab. As you can see, it didn't mind a rather ugly cut needed to remove weight on that side. (I've since rehabbed it more but I didn't want to sacrifice the blooms that year.)
Yes, Edgeworthia is an Asian import. However, it does not self sow and is not invasive. It is easy to root from a cutting dipped in rooting hormone. They also tend to sucker at the bottom. Lay a brick across a sucker and walk away for six months to a year, then cut the stem on the other side of the brick. Voila, you have a rooting that will grow surprisingly fast, blooming in as little as two to three years!
Edgeworthia is a good source of nectar for honeybees. Aside from occasional weather extremes causing floral failure, there are no serious pest or disease issues with Edgeworthia chrysantha. Occasionally bugs will nibble the leaves in summer, but they cause no lasting harm. I've never bothered to treat them.
Contributed by Liane Schleifer