In late March, I purchased my first three pre-bonsai trees from a nursery in Northern California. (I’m in Benton County, WA, climate zone 7A). All were 2 years old. I repotted the kishu juniper and the Zelkova in a commercial akadama, pumice, and lava mix. I left the Japanese Larch alone because it had already started to develop foliage. Here are the trees in photos I took yesterday.
Kishu is doing great.
Larch is developing brown tips and showing not much new growth in the last few weeks.
The Zelkova is just sad.
In early April, we got quite a bit of frost. Last week, we had temperatures of almost 100F. Today it’s about 75F out. I added dried peat moss over the soil last week as top dressing to keep in some more soil moisture. The top of the Zelkova died from the frost, but I was expecting better from the lower branches. Not sure what’s up with the Larch. I’m using biogold pellet fertilizer.
Any suggestions on shade, watering regime, fertilizer, soil, anything that might help these trees? Find a big pot with garden soil? Just keep an eye on them? Am I just in a bad climate for these Japanese species?
They should all do well in your climate if you can protect them from the extremes that you listed. The frost probably damaged the new larch shoots since it had probably pushed out in a warmer area. Same issue with the zelkova. I would put all of them in a location that is sheltered from the wind a bit and gets morning sun. Watch the watering until they recover and I would remove the fertilizer until the get some good growth.
2 Likes
Thanks for the response. By “watch the watering,” do you mean reduce watering and let them get somewhat dry?
Yes. You want the soil just moist before you water again. Trees with lots of roots can tolerate wetter conditions than those that were recently repotted, but still don’t want to be wet all of the time.
1 Like
Thank you, Marty! What’s the reasoning behind removing the fertilizer? It kinda makes sense on a gut level, but I’d like to know more of the biological reasons. That’s my old biology degree talking, though.
Chad
Nutrients are absorbed through the root hairs which are often damaged or destroyed during repotting. The fertilizer in the soil is in the form of a salt (organic fertilizers are milder salts) which can impede the new root growth so it is a good idea to not fertilize until the new roots are established. Since weak upper growth often results in poor root activity, it is also a good idea to withhold fertilizer until the tree is growing well.
1 Like
