Herbicide Considerations On Newly Planted Pines

Longleaf-DerrickO.-Entomosporium 003

We were out looking at longleaf pine seedlings established on a plantation south of town. They have just planted around 12,000 longleaf pines. They are planting at 720 trees per acre. The trees are placed 6 freet from one another and rows are 10 feet apart. This will allow space for mowing for weed control. Also note that the plug is a little out of the soil. This is to keep soil from covering that terminal bud. We don’t want to be too much out of the soil for concerns of losing water either. Once the trees are established, then weed control options will be considered.

Longleaf-DerrickO.-Entomosporium 002Not only do we need to follow the herbicide label and use recommended herbicides at seedling stage, we need to watch closely about our timing. We need to wait at least two months to apply herbicide over the top of long leaf and slash pines (2 inches of white feeder root  growth from 5 laterals), and one month for loblolly. Here are some thoughts on applying herbicides to newly planted pines for herbaceous weed control from UGA Extension Forester Dr. David Moorhead:

  • Be sure that the planted seedlings have started active root growth before herbicides are applied. Dig several seedling up and check for root growth into the surrounding soil. Cold temperature, dry soils or excessively wet soils can delay the start of new root growth. These photos (below) show root plugs of containerized longleaf seedlings. The plug on the left is a newly planted plug where root growth has not emerged from the plug. On the right, the seedling has active root growth into the surrounding soil – at this point it is safe to apply herbaceous weed control. With bareroot seedlings new roots should also be growing into the surrounding soil.
Photo by Dr. David Moorhead-UGA

Photo by Dr. David Moorhead-UGA

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