Hi! I just bought a house in Sylvania and noticed what I believe to be a blue spruce but it seems to have 2 colors of needles. Is this normal or a sign of distress?

Hi Christina, 

Have you observed any signs of pests or disease on the affected part of the blue spruce? Also, what is on the ground around the tree. It appears to be very dried out. Any dead or falling needles?

There are no obvious pests and no needles. The greener needles seem drier than the blue. The ground is pretty sandy in the yard. 

There are no obvious pests and no needles. The greener needles seem drier than the blue. The ground is pretty sandy in the yard.

Hi Christina, 

That's good news. The blue spruce is a beautiful tree. Glad you are looking out for it.

The blue color of blue spruce needles is caused by epicuticular waxes on the needles that reflect specific wavelengths of light. The more wax on a needle, the bluer it is. Neither the amount of wax nor the blue color is uniform across the species.

Greening can result from several causes. The tree produces the wax on its needles in spring and early summer. The wax can wear off over a rough winter or erode by wind, hot sun, pouring rain, and other types of exposure.

The causes of discoloration:

1. Air pollutants can cause the wax to deteriorate quickly. This is especially true of nitrogen oxides, sulphur dioxide, particulate carbon and other hydrocarbons.

2. Poor nutrition can also be one of the reasons. Application of pesticides can cause greening in blue spruce needles. This includes not just toxic pesticides but horticultural oils or insecticidal soaps.

3. Greening in blue spruce can also occur naturally over time as the tree ages.

You can try to stop the process though it is not a matter of flipping a magic switch. Instead, giving the tree the best care possible will give you the edge on keeping a blue spruce blue. It looks like your tree gets adequate sun with good drainage. Sufficient water is a concern as it looks very dry, though it has been a dry hot summer, hard on all plants. Watering may not be practical. I see someone mulched the area under the trunk. You could widen the mulch area under the tree as the root grow out to the extended branch width. Keep the mulch away from the trunk.

Volcano Mulching is an improper mulching technique where mulch is piled high against the trunk of a tree. This is often seen in commercial landscapes; look for it next time you go shopping! Please don’t do this at home. Mulch should not touch the trunk of the tree. The trunk was simply not meant to be covered and doing so invites decay and pests.

Finally, feed the tree in mid to late summer and repeat in the spring using a 12-12-1 fertilizer.

Enjoy your new home and your beautiful tree.