How to help my Colorado Blue Spruce
We have one (of two) remaining Colorado Blue Spruce tree in our yard that is looking distressed. To guess, I would say it is about 25 years old and about 45 - 50 feet tall. The lower, wider spreading branches are looking like they're dying from the inside (trunk side) out to the tips, only the outer part of the branch's needles are still green. The twin tree had the same issue, but earlier this year we had to cut it down as it was brown and thin out to the tips of the lower branches - only the top one third to one quarter looked green, lush, healthy. I've done some internet research and think it may be either the Rhizosphaera or Stigmina needle cast. Is that something you could confirm? Could you recommend a type of treatment (and where to purchase the tools/items necessary)? Thank you!
Blue spruce is susceptible to several fungal diseases such as rhisosphaeria needle cast and cytospora canker. Based on your photos we cannot say exactly what you may be dealing with. However, management is the same. We recommend keeping the trees well watered during dry periods if possible. Mulch around trees to prevent wounding by lawn mowers and string trimmers. Make sure mulch is no thicker than several inches and keep away from the base of the trunk. Prune dead wood during dry weather. No chemical controls are recommended. See our website for information on each http://extension.umd.edu/hgic/evergreen-needle-cast-diseases-trees-and-shrubs