Yellowing needles on evergreens such as pine trees cause concern and warrant immediate control to prevent spread and retain health. Because a number of factors cause the needles to turn yellow, you need to diagnose the cause of the discoloration before treating the problem and adopting strategies to prevent future outbreaks.
Cause - :
- A number of reasons cause yellowing needles on a pine tree. An improper planting site causes the needles on a newly transplanted pine tree to turn yellow.
- Lack of irrigation or exposure to extreme drought damages causes the needles at the top of the tree to turn yellow and wilt, before spreading downward to cover the entire foliage.
- Excessive salt or herbicide damage causes the tips of needles to turn yellow first, before progressing and turning the entire surface purplish-red or brown. Blights and needlecast diseases cause needle discoloration and spotting.
Treatment - :
- Treatment varies according to the cause and scale of the discoloration. Transplant the pine tree to a site that meets its growing conditions, or replant the pine positioning its root collar at ground level. Avoid planting the tree in wet soil, since roots fail to absorb oxygen, causing the foliage to turn yellow.
- Spread the roots in different directions in the planting hole. Provide a steady stream of water around the tree to alleviate drought stress. Douse the soil with water to leech out accumulated fertilizer salts that cause yellowing needles.
Prevention - :
- Plant the pine in a loamy or sandy soil with pH between 5.5 and 6.5. Adopt good cultural practices to keep the needles of the evergreen from turning yellowing. Needle discoloration not only causes aesthetic damage, but increases stress that makes the tree susceptible to diseases.
- Irrigate the pine tree regularly, especially during prolonged periods of drought, to keep the soil from drying. Follow a regular fertilization schedule to prevent over-fertilizing the pine tree. Minimize chances of diseases by adopting good sanitation practices and minimizing plant stress.
Considerations - :
- Sometimes, sudden exposure to drying winter winds or extreme temperature causes the needles to turn yellow before becoming brown. This discoloration is not cause for concern because the needles regain their original color in most cases.
Recommended Planters : Planters by Size
Choose planters according to size required for your plants for various purposes and locations.
Buy ready to use nutrient rich soil:
In general use a soil-based compost placed over a generous layer of drainage material such as earthenware crocks, pebbles or gravel. Water and feed regularly, especially while plants are bearing flowers and fruit, when a high-potash fertilizer is recommended.