Bambusa multiplex ‘Alphonse Karr’

by philinshelton on May 14, 2009

in Bamboo Plants

Most temperate bamboos make horrible house plants, but this subtropical beauty makes a great container plant indoors and out. The first time I saw Alphonse Karr bamboo, it was growing in a pot in and office building near a large window. Since most bamboos (especially the temperate, cold hardy ones we grow outside here) make poor house plants at best, I was surprised to see a vigorous plant with lush, green foliage growing indoors. Once I started growing it for myself, I found that Alphonse Karr is very fast to size up, even growing indoors. Compared to the cold hardy bamboos I grow in containers, Alphonse Karr is every bit as vigorous. Not only that, but it's much hardier than I would have expected from a "tender" bamboo. Last winter, my plants spent over a month in a dark, unheated, shop, with night temperatures well below freezing, for about two months. Canes Probably the most outstanding feature of this bamboo is the bright yellow color of the canes. You will see some random green striping, and with a little sun exposure, culms will develop a magenta/red blush. Foliage The leaves are fairly large, 5"-6" and remain lush green in our unheated hoop house down to about 25 degrees F. Growing it Well
Alphonse Karr over wintered in a dark, unheated shop

Alphonse Karr over wintered in a dark, unheated shop

As a container plant, Alphonse Karr bamboo can be grown outdoors even in mild frost. During the coldest months of winter, you can put it in an unheated garage or cellar for bout two months, without harming the plant, amybe even longer. Or you can bring it inside to grow as a house plant. It does best in a well lit space (i.e. next to a sunny window) but will tolerate even dimly lit interior spaces. Like most container plants, it's best to let the potting mix dry down to the point where it is barely moist, then saturate (water running out of the drain holes, and then some). There are oodles of fertilizers you can use to feed with. Water soluable fertilizers are probably the easiest, but you could use a time release granule, or even a commercial potting mix that already has fertilizer in it. As always, apply fertilizer following the rates recommended by the manufacturer. If your bamboo is happy, then you will have to divide it, or transplant it into a larger container every 1-2 years. Plants maintained in a "tall #5" container can be expected to reach about 8' high, but can reach up to 15'-20' in commercial-size containers (#15-#25).

{ 7 comments… read them below or add one }

Pete Bray May 17, 2009 at 11:28 pm

This is a bit off topic… can you tell me when the rhizome is most active? I think I read that the rhizome starts to spread in late fall? I am trying to figure out when the best time to put a blockade to prevent spread into my neighbors yard is? I pulled up huge rhizomes… 20 feet plus early spring. I gather that they start to spread after the shoots have leaved? So in fall??

philinshelton May 18, 2009 at 4:27 pm

I have read the same, that rhizomes spread after shooting, in fall. My experiece, the rhizomes can grow from spring to late fall, depending on the bamboo. Stops about the end of October. I don’t use barriers. I describe the process I use to contain running bamboos in one of my blog articles. Here’s a link:

Pete Bray May 21, 2009 at 2:04 pm

That’s good advice… the only reason I am using a partial barrier is to hopefully have the rhizome “deflect” back into my yard. Pruning the rhizome presumably weakens the plant, or, at very least, limits the number of sprouts in the spring, so would prefer them to “deflect” back into my yard (though who knows if they actually DO deflect… they may just run along the barrier rather than doing a complete 180?

philinshelton May 21, 2009 at 4:05 pm

Having seen this in action, I feel very safe in telling you that the rhizome is going to run along the barrier, so you aren’t going to get much deflection back into the grove. Still, it’s not a bad idea to have the extra safety net of a barrier as you propose. Just don’t count on it as a magic bullet for bamboo control.

Pauline Hadland February 27, 2010 at 8:36 am

How is the Alphonse Karr for dropping leaves? I want to place one in a container near my swimming pool.

philinshelton March 1, 2010 at 4:44 pm

It depends of course on the environment. In mild climates leaf drop is probably not going to be any worse and a deciduous plant of same size, probably less. Leaf drop will also be spread out over time, not all at once in the fall. If it gets too cold for this bamboo, and the leaves are damaged/killed, leaf drop will be more severe.

Debora November 29, 2010 at 11:43 am

i recently bought a “bambusa multiplex” but the species is not determined on the tag, would you be able to tell me by looking at pictures?
also i am growing it indoors, how wide do you think the pot has to be?
thank you so much, Debora

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