Plants look sick

Question

I have a bottle brush tree and two little john shrubs, zone 9, Las Vegas. They have been pruned earlier this year and I’ve worked with the soil in terms of compost, fertilizer, water, etc. They have bloomed a little bit, but not significantly. Now, they are yellow/green/red in color and still some of the branches are bare. Are they dying, or is there something else I can do to make them look better? Many thanks in advance and Happy New Year!

Answer 1

A pH problem could be responsible. The bare branches could suggest a disease like Verticillium wilt, especially if the branches are dying. Unlike in other plants, Verticillium wilt is usually mild in bottlebrushes, weakening the plant but not killing it. Please see the following articles:

http://extension.illinois.edu/hortanswers/detailproblem.cfm?PathogenID=26
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/verticillium-wilt/
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm
http://pss.uvm.edu/ppp/pubs/oh34.htm