For future reference I do use tall pots for Junipers when attempting similar. What I do though is usually is put in a rather long tie down wire often a foot taller then the pot. I then fill in the first 2/3rds with crushed stone or similar. Anything that adds weight for stability and drains ultra fast. I then cut a piece of plastic hobby mesh, thread the wire through, and slide it down covering the rock/stone. Plant and wire in