Winmagbar

Hello,I live in NE Oklahoma and roughly 3 weeks ago I planted six 3’ tall Basjoo trees. I was experiencing good growth on the basjoo for the first week and then after fertilizing them with 10-10-10, most growth has slowed way down . The Basjoo were planted in good loose top soil with commercial cow manure blended in, so maybe I over fertilized since the soil was already hot. I did also fertilize a red banana but it was planted in existing soil so maybe it needed the fertilizer, thus it’s outstanding growth. Sorry for the long baseline but here are my questions.
1. How often should I water, do they need to stay moist
2. With the low flow rate,is 4 hours too long when using a round soaker hose
3. What is the visual clues between over and under watering
5. They middle plants have grown around 12” in 3 weeks, is this a normal rate of growth for newly transplanted Basjoo
6 . Why are the plants on both ends of the row only growing much slower
7. Can I use liquid Sevin for pests

I really appreciate the help and sorry for the long post. I would have included pics but I have not used gallery yet.