Q: What are some reasons why a Palo Verde (Desert Museum) won't grow upwards?
Monday, January 4, 2016
Q: I live in San Diego and planted a small Palo Verde (I think Desert Museum) about a year ago. I water it twice a week and it has become pretty full; however, it hasn't grown very tall so it currently looks like a big bush. Is there some reason why it hasn't grown upwards?
A: I would check a few things first:
- Is the tree planted too deep? The top of the root ball should be at the same level as the surrounding soil.
- Are there girdling (circling) roots going around the root ball? If so, try cutting or slicing the roots to allow the roots to grow outward.
- Dig down about 6 inches to see if water is reaching that depth. If not, increase the watering. If water is pooling, decrease the watering.
Foster the development of a more dispersed root system and reduce the risk of wind throw by arranging irrigation emitters at varying distances from the trunk to encourage roots to "seek out" water and nutrients. Prune as needed to reinforce the structure and form of the tree. Periodic thinning is the most desirable method of pruning. Avoid hedging or heading back desert species, as this will only stimulate excessive branching. Do not remove more than 30% of the canopy during the summer, as this can lead to sunburn injuries that can later be invaded by wood-boring insects. Always use sharp tools that are cleaned regularly in a 10% solution of bleach.
Responder: Ted Lubeshkoff, RCA #513, Duarte, CA