Yellowing of Eastern White P ine

Asked February 16, 2019, 3:39 PM EST

My well established 20 foot+ Eastern White Pine is starting to show a slight yellow tinge on the needles this year. Its has been well mulched with shredded tree trimmings (2-3") and its own needles. The ground on the north side of the tree slopes down approximately 4 feet so drainage is not a problem. The ground is clay (live near Salem airport). I'm thinking some sort of nitrogen slow release fertilizer pellets but am unsure if I should remove all the mulch there or just spread the fertilizer over the mulch. Also what is the current thinking on type of nitrogen. I'm also needing to trim up my Sequoia giganteas. Can I just trim them back on side of these trees need trimming: or should I just remove these branches. These are very near the above mentioned pine and they show no signs of yellowing. Thank You

Marion County Oregon

1 Response

It is important to diagnose the cause for the yellowing of your white pine before deciding to fertilize. Yellowing can be caused by poor nutrition, but it can also be caused by other conditions such as needle disease or climate stress. Fertilizer can exacerbate some diseases or drought stress. I suggest you take some photos and also consider bringing a few branchlet and needle samples to the OSU Master Gardeners in Salem. If we eliminate disease and climate stress, then we can proceed to look at nutrition and possible fertilization.

As for pruning your giant Sequoia, it is probably best to remove the branches you wish to trim by cutting where the branch joins the trunk. Trimming them part way will either leave a dead staub or a multiple stem resprout that detracts from the natural form of the tree crown.