These plants can grow well in clay soil, as they thrive in our climate & the soil is clay. The raised mound & root trimming are probably not the best. If it looks OK, the roots are probably recuperating.
I do not know how big your plant is, but if you feed this plant right, & put it in sandy soil & full sun, a 5 gallon container should be 20 ft or more with many pups in at least a 4 ft box in 5 years. Proper feeding involves getting those roots to grow & developing a thick trunk. The thick trunk is important, as there are many tall specimens with skinny trunks. A 20 ft tall plant with 5-6 pups should have a root mass that would be pretty much pot bound in a 4 ft box. Some people have the opinion these plants should have their roots cramped. In my opinion, if you want to grow them big & strong give the roots food & room to grow. They also need plenty of watering in hot climates  daily in the summer.