Thanks AA & Gino, but my problem is not getting a bigger pot anymore.
It was inground last summer, then dug up & potted to inside. It grew like crazy all winter & I knew it was rootbound. Cannot just plant inground without acclimating it so I found a 65 gal pot (made of fabric) & that's where it is on north side of house. It is suffering transplant shock big time.
Whiskey barrel would be too small. This new pot is 33 inches across (see pics above), so it is big enough now. It's just a matter of hoping it will survive from the shock. Fingers crossed!
