Ask a Consulting Arborist Q&A: Tree Care Tips (Pruning, Water, and More)

Q: Why would a green giant thuja stop growing past 5 feet over 18 months?

Thursday, December 31, 2015  

Q: My green giant thuja isn't growing. It's about 5 feet tall and appeared vital for the first month after planting. But since then, all it's done is fill in the highest branches. In the approximately 18 months since I planted it, I have regularly watered it and fertilized it with Jobe spikes for evergreens twice a year. Here in Dallas, summers get hot, so I maintain a layer of mulch over the ground surface about a foot in diameter.

 A: This is a very hardy plant. Check the planting depth and drainage; root flares should be exposed, and drainage should be sufficient. Irrigation should be year-round and 10-15 gallons per diameter inch per watering. Feeding should be once a year with an actual 3-1-1 slow release. In the field, we call Jobes tree spikes "snickers bars." For a more thorough diagnosis, call an RCA.

 

Responder: Rick Zampino, RCA #416, Fairview, TX