In this instructional video, Harry Harrington walks viewers through the complete process of collecting a 100‑year‑old hawthorn yamadori and potting it up for bonsai cultivation. He explains why he collected the tree in late January 2020, describes the shallow chalk‑bedrock site, and details how the root ball was wrapped in damp sphagnum moss and plastic to keep it moist during transport. Harrington discusses optimal collection timing (autumn to early February, avoiding frozen ground) and the importance of preserving mycelium by not washing or soaking roots for difficult deciduous and coniferous species. He demonstrates careful root cleaning, pruning damaged roots with non‑metal tools, and the selective removal of weeds. The video outlines his custom soil mix—large pumice grains, chopped bark, activated charcoal, and finely chopped sphagnum moss—pre‑mixed months in advance and sieved to remove fines, emphasizing the benefits of non‑sterile, garden‑aged media. He advises using a pot just large enough for the root ball, wiring submerged roots, and never applying rooting hormone to existing roots. After back‑filling, the tree is watered heavily until drainage clears, a surface layer of sphagnum and hill soil is added, and pruning wounds are sealed with petroleum jelly while dormant. Finally, the potted tree is placed in a polytunnel and bagged for spring, with a note that further details are available in a behind‑the‑scenes series.
Chapters
This is a large Hawthorn Yamadori that I collected in late January 2020 after returning back to my garden in the late afternoon. Aged over 100 years, the tree spent its life growing in a shallow layer of soil on top of chalk bedrock. Unfortunately, the land is being slowly cleared by the landowners, but it has given me the opportunity to collect some of these trees. Many decades of repeated damage from local deer and rabbit populations have kept the tree relatively small despite its 7-inch girth. After digging up the tree, its root ball was wrapped tightly in a large plastic bag packed with damp sphagnum moss from the local area. You may notice that I've also wrapped sphagnum in plastic on the trunk to avoid any damage to the bark while I carried the tree over my shoulder as I came off the hill. A question I'm often asked is, when is it best to collect hawthorn? I collect in the autumn while the trees are still in leaf, all the way until early December and the first frosts here in the UK, but this is an unusual thing for anyone to do. The traditional time to start is as the winter buds begin to show a little color, which will be a bright red in early February in the UK, until the leaves are actually open. However, January seems to have been successful for me. Whatever the calendar date though, don't collect a tree when the ground is fully frozen. Leaving the roots wrapped overnight to ensure that they do not dry out, I returned to the tree the following morning to pot it up. With some species or younger trees, it can be advantageous to soak the roots overnight in water. However, with more difficult deciduous species and all coniferous species, it is better not to soak or wash the roots prior to Potting up for fear of removing the very beneficial mycelium that's in the soil. The roots are carefully unpacked, putting the sphagnum moss to one side to be used chopped up in my soil mix. Sphagnum moss is an essential part of recovering Yamadori as it has very many useful properties for root growth. As you work around the newly collected root ball, Look for damaged roots and recut them as necessary. A nice clean pruning wound will always heal better than a damaged or ripped root. Remove weeds and weed roots where possible, but don't be too meticulous. As the tree recovers, the presence of weeds and local fauna can be beneficial to the collected tree and help to stop the soil from staying too wet. Remove ground soil that contains no roots carefully. Using your fingers or a piece of wood. Don't use metal implements that won't give your fingers the same feedback as wood, and as you work, you just simply snap roots with metal objects. Although it may be faster, don't wash the roots with a jet of water. You need to keep some ground soil and its beneficial mycelium attached to the roots. You can see that this particular tree has a superb root system. There are many of the important fine feeder roots still attached to it. This is the result of ensuring that I collected the tree from an area of soil that remains damp throughout the year. Dry, fast-draining soils will result in Yamadori with just a few heavy roots that have grown great distances in search of moisture. Use a pot that is just big enough to contain the root ball. Too large and the soil will stay wet for too long after watering. Too small and you will need to remove even more roots from the tree unnecessarily. My soil mix consists of large grains of pumice, 6 to 14 mm in size, chopped bark, activated charcoal, and finely chopped sphagnum moss. Importantly, it has been mixed many months ago and has been allowed to cook outside in the garden. This is considerably better than using sterile soil straight from the bag. All fines have also been sieved out. A little soil from the hill and old roots are also added on occasion to increase the presence of the beneficial material Offering the tree up to the large 60 centimeter diameter pot, I do my best not to cut many roots, if any. However, on occasion it is necessary to prune back heavy roots that cannot be coiled back on themselves into the pot. The tree also is very firmly wired in using submerged roots rather than those that form part of the nebari and can leave scarring marks in the future. Never for any reason use rooting hormone on the roots. Rooting powder or hormone is useful for motivating top growth to produce new advantageous roots, but it can have the opposite effect when it's applied to existing roots. The soil mix is then added around the root ball, making sure there is no large air pockets where where roots can dry out. A wooden stick is used to push the soil in and around the root ball. The tree is then watered in very heavily until the water coming out of the drain holes runs clear. At the moment, I'm experimenting with not watering in the already damp and activated soil. However, I won't find out the results of this until next year. A layer of chopped sphagnum moss and some soil from the hill is then added to the surface of the soil before a final watering in. My last job is to work over the pruning wounds on the branches and trunk and make sure they are clean cuts for faster healing. A thin layer of petroleum jelly or Vaseline is sufficient to seal the wounds while the tree is dormant. Finally, the work is complete. The tree will now go into a polytunnel and be bagged up for the spring. For more details about this, please see my behind-the-scenes video series.
