Q:Â We have a bottlebrush tree that is failing to thrive. It does not bloom much, nor does it seem to put out that much new growth. We have had this house for 15 years, so it is older than that.
We have had to trim off several dead branches over the years and recently lost a big branch due to wind. We feed it and water it, but not overly so in either case. Would trimming it way back stimulate growth? If so, when? Are there any fertilizers or soil builders that might help?
A: Bottlebrush can live to be 50, so it could be suffering from old age. The most common problem with them is irrigation. Since they aren’t desert plants, they need deep watering, to a depth of 24 to 36 inches every couple weeks in the summer, every three weeks in the spring and fall, and every month in the winter. Drip irrigation on a timer is ideal. I know you said you water it, but you didn’t say how much, so that’s the recommendation in case you didn’t know. A general-purpose, slow-release fertilizer once a year in the spring or fall is all you need. You could also put a 1-inch layer of compost around the root zone, being careful to keep it off the trunk, to give it some slow-release fertilization when it rains or is irrigated.
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From the photo, it appears there are some dead limbs that could be pruned. Some varieties respond to hard pruning, but without knowing which one you have I wouldn’t recommend pruning it back too much. One-third is the rule of thumb to avoid too much stress on the plant. Pruning after flowering is the best time.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to
