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Winter desiccation or "Winterburn" is the discoloration or damage of the needles. In the spring, you'll notice needle discoloration ranging from orange to brown to purple. If you have several evergreen trees, it's common to see a large amount of variability. For example, one tree may have brown tips, while the one next may be entirely brown.
This relates to tree genetics, microsite, soil, and tree vigor before winter. It is common to see damage on the plant's south, southwest, or windward sides, but the whole plant can be affected. It is more common with young trees.
Why does this happen? The needles of evergreen trees are alive and will continue to transpire (release water) throughout the winter. Winterburn occurs when the amount of water lost exceeds the amount picked up by the roots. This is more likely to occur during sudden temperature shifts and extreme wind.
When working with soil amendments, there are many to choose from today. So how do you know which ones are right for your garden? Start with a soil test. A soil test is a window into the health of your soil and provides information like pH, organic matter percentage, and general fertility. Once you know your soil's quality, you can combine that with your plant's needs to choose effective amendments.
Your soil may need more nitrogen (add composted animal manure). If you're looking to improve your soil quickly, like in a vegetable garden, choose an amendment like cow manure which breaks down fast. For a steady feed all season long (in a perennial border or with long-term vegetables like tomatoes), opt for a material like compost which takes several months to decompose.
Another factor in growing healthy plants is soil pH. Soil tested as too acidic or too basic prevents plants from taking up nutrients. For example, we have acidic soil in my Northeast garden, and I need to lime my vegetable beds yearly. In regions where grounds are primary, sulfur can be added to adjust the pH to ideal levels.
Here is a useful list of all of the necessary nutrients to achieve good growth patterns.