Yamadori are pre-bonsai trees collected from the wild. After collection, a tree will usually have had major tap roots severed and need at least a couple years in a recovery container before it can be further worked on.
When learning to collect yamadori, it is important to have a respect for the age of these trees and the land they are growing on. Begin your collecting journey with smaller and less-valuable material so that you can be confident you know what you are doing by the time you collect impressive and old trees.
It is important to always have permission to collect from the owner of the land.
Additional resources that discuss the ethics of collecting yamadori:
Collecting yamadori often involves hiking in uneven terrain, far off the beaten path, and potentially alone in the wilderness with no cell service. It is important to be prepared with plenty of water and sturdy hiking boots. You may also want to consider a satellite communications device (such as the Garmin inReach mini) for use in an emergency. Who knows, you might get chased by a mountain lion.
Specific sites to collect yamadori will not be discussed.
Please ensure that you have read the section above on the ethics of collecting, and obtained permission from the owner of any land you intend to collect on.
Some public land in the United States that is managed by the U.S. Forest Service or the Bureau of Land Management is open to collecting. You will need to contact the individual ranger district or field office for the area you wish to collect and ask if transplant permits are available. The price is often $5 - $20 per tree and may come with limits on size, location, timing, and restrictions for non-commercial use only.
Individual states and counties in the United States may also offer permits to collect on their land, but it is not as straightforward to figure out who to contact to acquire permission.
Some collectors also utilize private land by contacting the land owners in areas they wish to collect and asking for permission.
The easiest locations to find trees that will transplant easily are in rock outcroppings where the roots have been naturally constricted and the growth of the trees stunted.
For most species, the best time to collect is in early Spring as the buds are swelling, but before new vegetative growth has emerged.
Many high-alpine conifer species will not be accessible in the early Spring due to heavy snow. In those cases, it may be best to collect in the summer during a period of dormancy through the early fall.
Common Junipers, which are notoriously difficult to collect, may do better being collected when it is a little warmer (late Spring or early Summer).
Give yourself enough time before the first freeze for new roots to grow.
When selecting a container for your newly collected tree, you will want to ensure that it is appropriately sized for the root ball that you have collected and that it provides adequate drainage so that water is not held in the container. Your container should be sized so that there is at most one or two inches of space between the edge of the container and the root ball. Many collectors build custom wood boxes to contain their newly collected tree, drilling many holes into the bottom. Others use rigid plastic nursery containers, often an Anderson flat. If the root ball is awkwardly sized such that large spaces are left in the container, you may wish to wall off portions of the box to prevent that soil from retaining too much moisture and allowing the roots to spread further than desired (we're trying to eventually reduce the size of this container, after all).
Next, you must decide on the soil mix you intend to use. Randy Knight, a prominent collector of hundreds of trees a year, uses 100% pumice for all trees where he has collected a good root ball. Todd Schlafer has been known to use a 50/50 pumice and lava (scoria) mix. Andy Smith uses a more complex mixture of 50% pumice, 20% lava, 20% pea gravel, 5% charcoal, and 5% crushed pine bark. One thing most conifer collectors agree on is that you want to sift out all particles under 1/8" in size to improve aeration and aid in root growth. Generally you will also want to avoid including particles above a 1/4" size.
Lay down a thin layer of soil mix into your container. You want to get the roots close to the bottom of the container, with one inch or less of soil underneath. You will also want to secure the tree to the container so that the roots do not move. There are several techniques for this -- try to avoid using important live roots to secure your tree when possible.
If you have collected a tree without many fine roots, Randy Knight has a technique where he uses small wood chips (coarse saw dust) to create a healing-in bed where he will triage trees for their first year post-collection. You can hear more about that in his Yamadori Aftercare video with Bonsai Mirai (for subscribers only).
Additional resources to help you pot your yamadori:
Potting up your collected pine PDF by Andy Smith
A PDF that details the methods Andy Smith uses to pot his collected pines (he collects hundreds of trees a year). These methods are broadly applicable to most conifer species.
Post-Collection Potting video from Bonsai Mirai (subscriber-only)
An informative video that demonstrates the technique of building a wooden box for a newly collected tree, and the nuances of securing that tree into the box.
Keep partially shaded and protected from wind.
Put them on the ground.
Do not allow the roots to freeze. Andy Smith has his best success when the roots do not get below 55 degrees for the first year.
When first starting to collect yamadori, it can be difficult to know how frequently you should be watering your trees. It is important to keep the soil free-draining and avoid water-logging your newly collected trees, as roots will need oxygen to grow.
While it can be easy to obsess over watering details, to provide a little insight into what might be considered average frequency, many of the prominent conifer collectors end up watering most of their trees once a day during summer. Randy Knight hints to this in his Yamadori Aftercare video, going so far as to say that he sprays down the canopy and live veins of his trees every day. Todd Schlafer and Andy Smith have also stated that they water their trees thoroughly every day during non-winter months, and I believe this generally holds true for Backcountry Bonsai as well. Obviously, if you have experienced significant rain, you may choose to skip those days, but keep an eye out for how much rain can actually reach the soil depending on the size of your canopy.
Heating beds can help you overwinter recently collected Yamadori to improve root growth and prevent freezing of the roots during the winter.
Ideal timeline for developing a collected tree by Andy Smith (near bottom of page)
An Arborist’s Approach to Yamadori by Anton Nijhuis
Collecting Trees from the Wild by Walter Pall
Collecting trees (Yamadori) by Bonsai Empire
Collecting basics by Brady Bonsai
Tips from Cho Bonsai
Asymmetry Podcast: Backcountry Boys (2018) by Ryan Neil
Asymmetry Podcast: Randy Knight (2018) by Ryan Neil
Asymmetry Podcast: Randy Knight (2020) by Ryan Neil
Asymmetry Podcast: Field Collecting at Telperion Farms by Ryan Neil
Yamadori Aftercare with Randy Knight from Bonsai Mirai (subscriber-only)
Collecting yamadori is hard. These are experts who have devoted significant time to collecting in an ethical and responsible manner to ensure maximum survivability. In most cases, the collectors will have a lot of inventory that is not on their web site.
Golden Arrow Bonsai in South Dakota by Andy Smith
Backcountry Bonsai in Wyoming by Dan Wiederrecht and Steve Varland
First Branch Bonsai in Colorado by Todd Schlafer
Other sources of collected material:
Cho Bonsai in Texas
High Desert Bonsai