Answer: They need full sun to bloom. Do they receive 6-8 hours of full sun daily? Since they look healthy, I'm assuming they are watered effectively. They are not heavy water users, but they do take a bit more water than native or other desert-adapted plants. Next year, during late winter/early spring, just before new growth starts, you might try fertilizing with a product formulated for flowering plants. The middle number on the package should be higher than the other two, e.g., 5-10-5 or 15-30-15. This represents phosphorus, which promotes blooming. I wouldn't fertilize now, because feeding promotes tender new growth which is susceptible to frost damage, and bottlebrush tends to get hit with frost damage at about 20 degrees F. Make sure the plants aren't receiving nitrogen fertilizer from a nearby source, such as a lawn. Nitrogen promotes foliage growth at the expense of blooms. Finally, it may be that the plants are just taking a little longer to establish their root systems and start blooming. I hope this info helps.
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