While Pines Recently Planted

Asked September 13, 2017, 8:31 PM EDT

I planted 3 potted white pine trees about 6 weeks ago. They are about 36 inches tall and nicely filled out. Recently they have developed some yellow needles that I'm concerned about. Am I watering too much? Too little? The sold is about 6 inches of topsoil and then sandy soil. Or is this normal?

Hennepin County Minnesota

3 Responses

White pines require acidic soil. Check the pH of your soil by sending a sample in to the soil testing lab.

White pine needles do turn yellow in the fall but on your pines it is the new leaves that are turning yellow. so iron chlorosis should be considered. Please see the information below.

White pine needles turning yellow

George Weigel  Special to PennLiveBy George Weigel | Special to PennLive
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on November 03, 2008 at 10:13 AM, updated November 03, 2008 at 10:33 AM
George WeigelThis is normal pine needle drop in fall. Notice it's only the inner, older needles that are yellow.

Q: Some of my young white pines have yellow needles. Will an application of lime help now, or perhaps some Miracid in the spring - if they are still living then?

A: You're seeing the old yellowing-white-pine-needles trick - one of Mother Nature's most popular fall garden tricks.

It's normal for white pines to show a lot of yellow needles this time of year - so long as it's the inner needles. White pines are notorious droppers of older, inner needles each fall. The yellowing and subsequent drop is more pronounced in young transplants, in drought years and in other stressful situations.

If the branch ends still have green needles and the roots are fine, your trees should be just fine without you doing anything. If all the needles are turning a sickly greenish-yellow, it could be a nutrition problem that an acidifying product such as sulfur or Ironite would help. But if whole trees are turning completely yellow and then brown, that would be bad news - possibly a rotting of the roots in wet clay, blowback from too-deep planting or some other fatal condition.

Thank you ! I will test the soil, that makes good sense.