A customer writes: Hi Sherry, Back in the fall my husband and I purchased four clumping bamboo plants. We bought two green and two yellow thin stalk kinds that are supposed to grow about 20-30 feet. You said that by the end of the summer we will have our beautiful privacy bamboo fence. I am forwarding you two pictures of the bamboo. The two green ones have grown taller but are very spindly and have not branched out at all. The two yellow ones are full but have hardly grown any taller. None of the plants have had any new canes growing out from their center so there is much space between them. As you will see in the pictures we have a very unattractive view from our side back yard.
Thanks for the photos. It helps to see what you describe.
The main thing you have to realize is that plants bought in the autumn of 2008 have not yet have gone through their first season of above-ground growth. That's why you haven't seen any new canes yet. All autumn, winter and into the spring they have been establishing their roots in what hopefully was soil enriched with manure, compost, peat or our own Bamboo Booster mixture. From now through summer and into the early fall, the roots will be sending out new shoots. Those shoots will be this year's growth. The canes that emerge over the next few months will grow taller and be a larger diameter than the original canes in your photos. Assuming you irrigate regularly - especially during this very dry period when the bamboos need water to grow - by the end of this summer your bamboos will have many more taller, thicker canes and the area along your fence line will begin to look like the hedge you imagined last autumn.
To encourage more growth this summer now is an excellent time to apply top dressings of any or all of the following: Compost, manure, peat, topsoil. Mulch your plants with leaves, pine needles, wood chips, pine bark or, my favorite mulch - grass clippings. You can also add fertilizer around the plant base - we recommend Dynamite time-release but a regular formula will work too. The important thing is to give your plants food - fertilizer, soil amendments, mulch - so they can eat and grow. If you don't use Dynamite, look for a formula with high nitrogen, the first number, because bamboos are heavy feeders.
Now's also a good time to check your sprinklers to make sure the plants are getting adequate water. And be patient. If you do these things, by the end of summer you're existing bamboos will be surrounded by bunches of new larger, thicker, taller canes.