I finished helping Billy taking out the Sarcococca hookeriana var. digyna that I started yesterday, then we had a Tree Planting Masterclass. This was given by Herbaceous Team Leader Alistair Penstone-Smith. First he talked through what to look for when selecting a tree, as trees are a long-term investment, it is particularly important to choose a good quality tree, to understand how it grows and how to maintain it. There are trees with special characteristics and having knowledge of these can be essential to the planting and treatment of the tree - e.g Eucalyptus establish well as young plants but not as mature or semi-mature.
We looked at actual young tree stocks samples that demonstrated different examples of what one should look for:
- Seeing that the stock was good, root systems are well developed and that it is not pot bound, overcrowded or if the roots were growing out of the pots.
- If it has a good shape, e.g. strong leaders and apical dominance and to avoid weaker unions like co-dominant stems.
- To not have any pests & diseases.
- If it is grafted - that the quality of the graft is good
We were referring from Matthew Pottage's Tree Planting & Selection notes from 2011, see this for more details.
We looked at different examples of well & badly planted trees, including the way that that they have been tied and supported. One of the things that stood out for me was that the buttress flare of the base of the tree was not to be covered and that distinctly almost all trees have a flare (Photo 1).
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| Photo 1: Example of a badly planted tree with flare covered. |
Then Alistair demonstrated planting a Styphnolobium japonicum 'Pendulum':
- He dug a hole around three times the size of the root ball of the container of the tree and approximately a bit more than the height of the container. Soil dug out of the hole was placed on a canvas for ease of transporting.
- He took the tree out of the container, knocked off most of the soil, teased out the roots more, pointed any roots that were inclining inwards outwards. After this was kept covered so that the roots of the tree would not dry out until it was ready to be planted.
- He fluffed the soil at the bottom of the hole but not too much as the soil at Wisley is light and to avoid subsidence afterwards, and stabbed holes with a fork in the side of the holes to ease root growth.
- A small mound/ platform of soil at the base was created and compacted by foot (Photo 2).
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| Photo 2. |
- Mycorrhizal fungi was placed directly on the roots. It has been debated whether this is necessary or not, or if this helps.
- Dug out soil was then returned to the hole and firmed up by foot with toe pointing to tree so that tree is not too pressed down.
- Dug out soil was then returned to the hole and firmed up by foot with toe pointing to tree so that tree is not too pressed down.
- A ring of organic matter was then placed on the surface around the tree in a doughnut formation.
- Then a stake approx. a metre was malleted into the soil 45°C about an inch away from the tree. This tree required a stake but not all trees do. It was positioned with the prevailing wind in mind - so that it blows away from stake rather than into it. Different size, kind of staking etc. may be considered for different kinds of trees.
- Then he tied it in with a plastic & rubber tie, that has a soft foam wedge that allows for an approximate inch gap between tree and stake, so that they don't rub and it allowed for enough flexibility so that tree can grow strong by itself.
We then worked in twos and applied the same steps of methods. Me & trainee Sally planted two Metasequoia glytostroboides in the Pinetum.
- Then he tied it in with a plastic & rubber tie, that has a soft foam wedge that allows for an approximate inch gap between tree and stake, so that they don't rub and it allowed for enough flexibility so that tree can grow strong by itself.
We then worked in twos and applied the same steps of methods. Me & trainee Sally planted two Metasequoia glytostroboides in the Pinetum.