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Thursday, May 19, 2011

Air layering a redwood

Today's post is going to explain how to air-layer a15 gallon redwood ,  in the beginning of what will be a long term project . I hope to, through several methods, create several trees from this one and eventually plant them together as a group.

This tree has been in a southern California nursery for a number of years. It is in a 15 gallon can and is about 10 feet tall. I got it in the beginning of the year. The first thing I noticed was that it was completely root bound . So the first step was to trim some of the old roots and get it planted in some new soil. This was done in late February and it is now showing lots of new growth so I decided it was time to get started

Air layering is a method used to obtain stock from an existing plant. You can literally make new roots grow in the middle of a plant. Using this method one can obtain fairly mature materials relatively quickly.
Today I'll be using a grafting knife to cut the bark, some rooting hormone, bonsai soil and a plastic nursery can. Another way is to use Sphagnum moss and plastic wrapping instead of soil and a pot.

During the process of air layering, it is necessary to remove the bark, the cambium, and the phloem layer cutting away about a 1-inch wide ring of these tissues from around the circumference of the tree.  After removing a ring of bark  the area is treated with root hormone and either sphagnum moss and plastic or bonsai soil and a pot is placed around the debarked area. I'm using the soil and pot in this case .
After cutting the ring of bark away. I dusted it with rooting hormone. The next step is to fasten the pot to the trunk  around the cut. I used wire to tie the pot together and to hang it from branches above. I then lined the bottom of the pot with sphagnum moss to keep from losing soil.
Next we fill the pot with soil so that the cut area is completely covered. Now we water and wait.

How it works-The layer just under the bark is a layer of actively dividing cells called the cambium, the next layer of cells called the phloem it is responsible for the transportation carbohydrates and other photosynthates down from the leaves to the lower parts of the plant. The layer beneath phloem is called the xylem; it transports water and mineral nutrients from the roots and soil up to the leafy parts of the tree. Removing the bark, cambium, and phloem prevents carbohydrates and photosynthates from flowing down the trunk. It still allows water and mineral nutrients to flow upward to the leaves via the channels in the xylem, thus keeping the leafy portions of the tree from drying out and maintaining them with an adequate supply of nutrients. Removing the cambium layer prevents the regeneration of phloem and healing over of the wound, the carbohydrates and photosynthates flow down the trunk and collect at the girdling site. The presence of this excess of carbohydrates and photosynthates at the girdling site, plus the presence of the water in the soil or sphagnum moss, causes dormant adventitious buds in the area to grow into roots. The most important thing at this point is not allowing the soil or moss to dry.
Redwoods root fairly easy so I anticipate having enough roots to separate the two trees by next spring. In the meantime I will also take cutting from the parent tree. It'll be awhile before there is any more substantial progress on this project. In early June I'll take a bunch of softwood cuttings from the parent tree. Hopefully in the next two years I'll be able to produce enough material from this one tree to create a group planting of Redwoods.
I hope you enjoyed this post, thanks for reading it. If there are any questions or comments please feel free to post them.


  1. I just stumbled upon your site for the first time. This is wonderful, I absolutely LOVE IT!! Thanks!

  2. I am trying a layer on a large redwood as well. Does not seem to be taking yet. Any advice? Thanks

  3. Hard to say without knowing how and when you did it or if all the cambium layer was removed. It took this one almost a year to get enough roots to separate.

  4. Thank you I have been contemplating this for some time now.I just was not sure how well a coastal redwood tree would take to air layering.I have 13 rather large redwood trees planted at the top of the hill in my back yard. I will be trying to air layer a few off these trees this next spring. How have yours turned out?

  5. It's been sitting in the back of the nursery just gaining strength. Southern CA isn't the best palce for them but so far so good. As long as you make a clean cut and remove all the camrium layerand can keep the layer from drying out you should be ok.