Fallopia Multiflora Care

ABOUT 
An herbaceous perennial vine native to central and southern China that can reach lengths of 6 -12 ft. Also known as "Chinese Knotweed." 

(This is my personal plant, she's my pride and joy.)

FAMILY 
Polygonaceae 

LIGHT REQUIREMENTS

Bright indirect to semi-shade - I keep my mother plants pretty close to a grow light and they're doing very well (just keep an eye out for leaf curling - an indication it's getting too much sun.) That said, in their native habitat they can be found in the forest undergrowth, so I suspect they'd do fine in shadier spots as well.

TEMP / HUMIDITY 
55 - 80° F (12.5 - 26.5° C) / 60% + Humidity.
(The listed values are the averages for their native habitat.)
I've actually not found these guys to be very picky about temperature and humidity, within normal ranges. (They do not do as well in temps above 90° F and are prone to melting if they get too hot.) If you live in a place that experiences colder, dryer, winters (like myself) you might just want to consider moving it near a humidifier, at least during those months. 

WATERING 

These plants are so. so. so. thirsty. I have literal swamp plants that don't chug water as greedily as these guys. I recommend keeping them pretty much constantly damp. Do NOT let their substrate dry out completely. I cannot stress enough how quickly they will crisp up on you if it does. (A very expensive lesson I learned the hard way.) 

Mine get a drink every 1-2 days. My plant tent is kept very hot though, so your mileage may vary. Until you get a feel for how they behave in your environment I would recommend checking frequently (every 2-4 days) and watering as needed. 

GROW MEDIA 
I grow my Fallopia in a 70/30 coir and perlite mix (with a bit of coco husk and activated charcoal thrown in) but even a standard potting mix would be fine. These guys prefer a denser, more water retentive, medium. They can also be grown in moss, and I do all my props in Fluval Statrum (though I wouldn't recommend leaving them in Fluval long-term.)

I would caution against any of the chunkier type mixes, or LECA. I do know some people that have had success in Pon, though I've not tried it personally so I'm hesitant to make any guarantees there. 

GROWTH RATE 

On a scale of 1 (slowest) to 5 (fastest) they are a 10. 

EASE OF PROPAGATION 
On a scale of 1 (easiest) to 5 (most difficult) I would say they're a 3 for beginners. More experienced propagators likely wouldn't struggle at all. They're really not as bad as everyone says, and even if they were, they grow so fast the losses aren't as catastrophic as with other plants. 

TOXICITY 
In humans - Reynoutria multiflora is actually listed in the Chinese Pharmacopoeia and is one of the most popular perennial traditional Chinese medicines. Caution must be taken, however, as overconsumption can lead to hepatitis. 

In animals, this is all I could find - "No toxicity or death was observed in mice [given] oral doses up to 100 g/kg during 14 days of observation." But as with anything that causes liver toxicity, I probably would not recommend letting kitty (or doggy) (or baby) chomp on it. 

Source 

ADDITIONAL INFO 
Pruning these guys can help encourage variegation. If you notice a vine is starting to revert (or go too pink), give it a trim to activate new growth points along the stem. 

Lastly, while they have a reputation for being dramatic plants, I don't really feel that's a bad thing - If they're unhappy, they'll let you know it. Underwatering will cause the plant to crisp up on you, overwatering may cause edema especially on the variegated leaves. If the plant becomes stressed about... anything, it will wilt on you. Listen to what it tells you, and you'll get on A-OK. 

If you have any questions, or some advice of your own to offer, please feel free to comment below. 

Thanks so much for stopping by!