Spruce trees are native to the northern temperate and boreal regions of the Northern Hemisphere. They comprise the genus Picea, with roughly 40 species of evergreen and timber trees. Spruces are pyramidal trees with whorled branches and egg-shaped or cylindrical cones. Some species are ornamentals, and many are cultivated as Christmas trees. Like most plants, spruces can be prone to sickness and disease, and may die if not properly cared for.
How to save a dying spruce tree
Determine what is ailing your tree.
You cannot save your tree unless you have determined the cause of the problem. Note what type of damage or disease is affecting the plant, which parts are affected, and whether the tree needs treatment. Inspect to see if the needles have turned brown or purplish, check whether the damage is on one side only, and examine both lower and upper branches.
Check that the tree is in the right location with the correct soil.
Make sure you are watering the trees according to their needs, and only giving supplementary water when the top three inches of soil are dry to the touch. Protect your trees from winter burn by planting one or two rows of wind-blocking trees on the windward side. See to it that the trees are planted in a suitable location and that the soil is not waterlogged, or the roots could develop root rot.
Check for and eradicate fungal diseases or pests.
Fungal infections like Cytospora canker could attack spruce trees. This is characterized by browning needles on the lower branches. Control the disease by pruning back the affected branches to the next lateral branch, and about four inches from the affected area. Spray your pruning shears with disinfectant and allow them to dry between cuts. If left untreated, this fungal disease could kill branches and, while it does not kill the entire tree, it can make it very unsightly.
Spruce needle rust is another fungal infection that appears on the needle tips of white spruce trees. During mid-summer, the needles turn yellow with orange or white projections. It is unlikely to kill the tree, but the affected needles will fall off during the fall season.
Pests like white pine weevil also attack spruce trees, causing them to bend like a shepherd’s crook. The needles will also start to fall off. This is fatal for trees that are less than four feet tall. Exterminate the pests by pruning away all dead tissue and dispose of the pruned branches. Sterilize the pruning shears with a household disinfectant after every 10 cuts.
Other pests that could attack spruce trees include sawflies and budworms. If they are left untreated, these pests can defoliate and kill the trees in a period of three to four years. To exterminate them, spray the affected areas with a solution of insecticidal soap and water. Repeat for at least a week until the infestation has been eliminated. You may have to hire tree professionals to treat the tree crown, especially for tall trees.
Tips for reviving ailing spruce trees
- Prune away dead or affected areas to avoid further infestation or disease.
- Provide deep watering at least once a week; the water should reach down to at least 12 or 15 inches. For soil with a high clay content, the watering should be every two weeks.
- Avoid light watering, as this could encourage roots to grow too near to the surface.
- Give a final deep watering during the late fall, before the ground hardens or freezes.
- Mulch the area of the root spread to retain warmth during winter and retain moisture during hot weather.
- Check the soil pH and make any adjustments necessary for the trees’ needs. To raise the pH, use compounds containing limestone, and to lower it, use aluminum sulfate or sulfur.
- Fertilize only during spring and early summer. If you fertilize during late summer or fall, it could encourage new growth and put extra stress on the trees.
- Use fungicides to protect the trees from fungal diseases; apply only after pruning the affected areas.
- Provide burlap or tree wraps to protect the trees during the winter season.
- If you are uncertain as to why your trees are dying, contact a certified arborist to evaluate the problem.
Conclusion
Spruce trees are widely cultivated because their wood serves many purposes, such as for construction and furniture. These coniferous evergreens are prone to diseases just like other trees, but if treated promptly they can be brought back to full health. Be sure to identify the reason the trees are dying, and check the soil’s pH and drainage. Treat fungal diseases and pests promptly, and ensure that the trees are deep-watered at least once a week.
Image: istockphoto.com / Maria_Ermolova