Black Pine repotting

Posted by on Jan 12, 2015 | No Comments
Black Pine repotting

Repotting season is here in Northern California and I’m getting started with some of the trees that I own that are most in need of repotting. Normally, I would start with deciduous material in early January and then work on conifers later in February and even early March. For San Francisco, the winter season is more a rolling brown-out than a complete black-out. As of the new year, most of my elms are just turning yellow to drop leaves while the Ume and some native deciduous oaks are already starting to move new flowers or leaves.

This is the 2006 seedling batch Black pine #20. I have 20 of the first batch left and this is my least favorite, although I can’t say for sure why that is. It’s got a smaller trunk, with movement only right at the base, above which is a largely straight trunk that has little interest. I believe the tree has not been repotted since it was put into a pond basket in 2008 or 2009. I probably scraped off the top soil once or twice since then but it’s apparent that the tree is in need of repotting even though the pond basket keeps the roots from getting too long and circling the container.

A lanky nine year old pine.   The tree was candle cut on the lower half last summer but the upper sacrifice section was allowed to grow freely.

A lanky nine year old pine. The tree was candle cut on the lower half last summer but the upper sacrifice section was allowed to grow freely.

The soil looks loose on the surface, but underneath it's quite solid and shedding water.

The soil looks loose on the surface, but underneath it’s quite solid and shedding water.

The side of the rootball after scraping the top a little and removing it from the pond basket.   The soil is completely trapped in a matrix of micorrhizae and pine roots.   The mycorrhizae shows the pattern of the plastic basket.

The side of the rootball after scraping the top a little and removing it from the pond basket. The soil is completely trapped in a matrix of micorrhizae and pine roots. The mycorrhizae shows the pattern of the plastic basket.

On the bottom of the rootball the roots are not circling like in a bonsai pot, but they are growing in a matt that is quite dense.

On the bottom of the rootball the roots are not circling like in a bonsai pot, but they are growing in a matt that is quite dense.

After combing out the side and top the structure of the roots that a pond basket produces can be seen.   There is a multitude of fine branching and the density of the roots is quite high.

After combing out the side and top, the structure of the roots that a pond basket produces can be seen. There is a multitude of fine branching and the density of the roots is quite high.

For this tree and about half of the 2006 batch, I’m starting to pot them down into smaller containers so that I can get them into the small bonsai containers that they will eventually inhabit. I cut off the top of the sacrifice and pruned the rootball back on the bottom and sides to fit it into an 8″ colander that is about 1/2 the volume of the pond basket.

Rootball trimmed and tree newly anchored in a smaller colander.   The root pruning removed roughly 50% of the volume of the rootball.

Rootball trimmed and tree newly anchored in a smaller colander. The root pruning removed roughly 50% of the volume of the rootball.