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