How to care for established bamboo plants

A customer from Riverview, Florida who purchased several Green Hedge clumping bamboos (Bambusa multiplex 'Silverstripe') emailed to say:

About 4 years ago I bought some bamboo from your lovely property. We love it and it did everything you said it would. It blocked a two story house that had been built behind us and provided a beautiful screen for our viewing pleasure. My question has to do with keeping the bamboo as a smaller clump to fit the area it is in. When new stalks come up do I dig it up or just cut it at ground level? Can I thin it a little from the middle by cutting stalks shorter or will they get new growth on the cut stalk like some plants do? And lastly, since this is such a prolific grower is it really necessary to feed the bamboo or does it need it to keep a green color? And what do you think is the best food for it?

By the way, this bamboo went through those horrible freezes we have had for the last two winters with flying colors. I couldn't be happier. When the rest of my plants and bushes were devastated the bamboo was our shining star.

A 6-year-old clump of Green Hedge bamboo

My response:
The best way to maintain a clumping bamboo once it has reached the size you want is to knock over new shoots when they appear around the perimeter of the clump.  Kicking or knocking over the young shoots stops that shoot from growing.  During the summer above-ground growing season, other new shoots may still appear but when they do, they can be knocked over as well. 

Another way to control the size of a clump is to cut back on watering and fertilizing once the circle of bamboo has gotten as big as you want it to be.  A mature clump of bamboo does well even without extra water and fertilizer. 

New shoots cannot be dug up and transplanted.  First of all, digging through a mature clump of bamboo is extremely difficult since the root system is so dense.  If you do manage to cut through with a reciprocal saw, ax or specially designed shovel, you would only want to cut out mature, fully leafed canes.  New shoots would have to grow up and leaf out before they can be divided off.

Any time a bamboo culm/cane is topped, it will not grow any taller.  It will, however, get leafier below where it has been cut.  Cutting out canes from the center of a clump provides a more open appearance.  Although new shoots sometimes come up in the middle, their tendency is to appear around the perimeter.

The fertilizer we like best is a 6-month time-release formula (18-6-8) high in nitrogen, which is what bamboos need for optimal growth.  We can send you a 1#, 3# or 6# package of fertilizer if you are interested.

Bamboo Q & A

A customer from the Orlando area who recently purchased and installed several Blue Timber (Bambusa chungii) clumping bamboos wrote with a few questions:

Hi Sherry,  How are you?  I hope this finds you doing well.  I am writing to ask some specific questions about our Bambusa chungii that arose after reading your wonderful blog. I find myself going back to your blog almost daily to look up something or read what you’ve written about a particular topic. 

OK.  First off, irrigation.  As you may recall, we purchased 5 Bambusa chungii from you. They are now integrated into our driveway landscape, placed about 10’ apart.  I have redone the irrigation system for this area, using a drip line with two dedicated lines for each plant (well, one has a line and a nearby spray head).  I have placed two of these micro-bubbler irrigation heads about an inch from the vertical culm of each bamboo: http://www.amazon.com/Orbit-Irrigation-67110-Micro-Bubbler-Stake/dp/B002R9O4OK.  This way when I turn on the sprinkler system, each plant gets a dedicated shower with a specific radius range of about a foot from the base of the vertical culm.  I have also added mulch around each plant.  We have a lot of oak trees here, so we have leaves galore.

OK, on your blog I read a comment from someone asking about newly planted bamboos and this person mentioned watering each bamboo for 2 hours.  Wow, that seems like a lot.  I turn on the bamboo zone for 10-12 minutes twice a day, then twice a week in addition that zone is part of our overall watering schedule (in Winter Park you can water two days a week) and the bamboo zone goes on for 25 minutes.  All the bambusa chungii now have leaves sprouting from the joints of each culm.  On all but one plant the leaves have no yellow; one of the tallest bamboos has some yellow leaves.  There are no curling leaves (indicating lack of water).  Yet, still I wonder … am I under-watering?  Do they need more than this?  Please advise.

Next, fertilizing.  As you may recall, we got both soil and Dynamite from you which were put into the planting as you direct in your planting instructions sheet.  Some bamboos have been in the ground for 3 weeks now, some about a week.  So soon (the one-month mark) I was going to add fertilizer.  My local hardware store has been having trouble getting Ironite http://www.ironite.com/.  They told me that Ironite has re-formulated the mix and it is now hard to get.  Not sure when they will have the Ironite.  So … I can use something like this:  http://www.seedland.com/mm5/merchant.mvc?Screen=PROD&Store_Code=Seedland&Product_Code=FERT-423403-15&Category_Code=FERT-453284.

Should I use both, assuming that Ironite becomes available soon?  Can I start fertilizing after the 4-week mark?

Thanks again for all your good information.  It’s fun to check in with Beautiful Bamboo by listening to other people’s questions and thoughts.  Thanks too for your excellent comments on Metalifestream. 

My response:

Hi Barry - I'm glad you are finding my blog helpful.  Have you used the "Search this Blog" feature yet?  If not, you might find that useful when seeking out information on specific topics.  Concerning your questions, let's start with irrigation.  From your description of the plants' new leaves, it sounds like you are giving them adequate water.  Bamboos like water and it is difficult to give them too much but the amount you are doing seems perfectly fine for plants in a shady, well-mulched location like you've given them.  Especially during this year's rather moist springtime.

Concerning the fertilizer, you already applied sufficient fertilizer to last 6 months when you planted the bamboo and used Dynamite, a 6-mo. time release fertilizer that we sell at the nursery.  The fertilizer you linked to would be a good choice for the future but not necessary for immediate use.  If you use the one you linked to in the future, you can apply it every month since it is not a time release formula but be sure to follow the application directions since regular non-time release formulas do have the potential to "burn" plants if applied incorrectly.  What you can always do however, is apply organic material around the existing bamboos.  Just like with water, bamboos thrive when given an abundance of organic material such as compost, manure, grass clippings, leaves, etc.  So right now, don't apply additional chemical fertilizers but do pile on the organic matter.

Ironite is usually available at Lowes, although I haven't checked recently.  Newly planted bamboos usually don't require Ironite applications.  Some browning of the leaves is normal, especially following transplanting, and as long as new leaves are forming, don't worry about others leaves that fall off.  Focus instead on all the new growth that's just beginning to happen now and will continue to happen through November.

How much is too much fertilizer and mulch?

A customer in Orlando asks:
I’ve been reluctant to put down a lot of pine bark so as not to interfere with new canes coming up. Am I being too careful? Inasmuch as I planted the bamboo November 1, am I being too careful in waiting til May 1 to apply Dynamite again? I don’t want to over-fertilize.

My response:
About the Dynamite, there's no need to fertilize again until May since the beauty of a time-release formula is that it emits a slow but steady amount of fertilizer over a six month period. As for the mulch, you can place a light mulch around the plants at any time. The new shoots will push through the mulch with no trouble. As the plants mature, you can add a thicker coverage. Mulches help plants retain moisture while reducing competition from weeds and adding some nutrients to the soil.