Hi all,
I collected a small ponderosa pine in August 2019 and it has done well overall. I wintered it on a heat bed and there are roots appearing from the bottom of the container. However, very recently, in the last few weeks, I noticed some browning of the foliage on a lower section of the tree. The apex, and other parts of the lower section are still looking healthy. Does anyone have an idea of what this is, how I can fix it, or at least prevent it from spreading to other sections? Thank you!
After initial collection in August 2019:
Current healthy foliage in the apex:
Current browning foliage near the base:
Some of the entire brown needles at the base of each cluster appears to be last year needle drop, probably delayed by being on heat bed. Some of the yellow can also occur d/t stress of collection. Also during the winter time, pondos yellow up significantly (they are alternatively called "yellow pines."
A few needles here and there appear to have needle cast which creates those yellow brown spots in the middle of needles and also that banding which your tree is experiencing.
Check out Mike Hagedorn's site. He had a nice blog post last year about overwatering needle yellowing vs needle cast. Many of the pondos I have seen in our club all have had issues with pine needle casts.
Good that the tree is making new roots. Also push on the apical buds. They should be hard and sharp, not spongy and soft. All this would indicated general health.
Needle cast is not usually fatal, but can weaken tree in container, and also looks bad. I'd isolate the tree from other pines and treat it with Daconil (available at garden centers, HW stores and online) once the weather gets warm. Please cover the soil surface and use respiratory protection if you can find it.
Hope that helps.
Andy
Thanks for the great info and tips! I suppose this could be a delay on one of the branches. I brought the tree to Chatfield meet up last week and had Larry take a look and he suspected like you did that some of those needles are older and he wasn't too concerned. Larry also suggested covering the soil with some sphagnum. I noticed that a lot of the collectors that I've read/listened to like Randy Knight or Backcountry do not seem to use top dressing on the pumice for their recently collected trees. Ryan Neil also thought that a higher oxygen ratio for newly collected trees may be best and that drying out a bit is good for root recovery compared to when they are in a smaller bonsai pot. Any thoughts on that?
@Matt Wright I do not use top dressing or anything but pumice for new trees. However, once a tree has survived a winter and you're seeing the signs of strong growth that Andy described above, you can certainly use a top dressing. Like all things soil/water, you need to be careful to allow the soil to dry out some in between watering. That will be dependent on weather, soil components, wind, etc etc etc and unique to your yard.
I have top dressed some of my collected pondos, but moss doesn't grow very well on the pumice for me.
@Nicholas Box Thanks -- appreciate the advice!!
@Paul Koenning What do you think?
I spent some time looking through https://www.fs.fed.us/rm/pubs/rmrs_gtr241.pdf but I can't tell if that looks like one of the common needle blights(Dothistroma pini) or similar.
thanks for the link, I'll take a look!