For the size of plant they look awesome, if you want to get them bigger I would increase the size of pot they are in or do a raised bed , the plant will grow to the size of the root ball , so if you can have a large root system the plant will grow big , I do my plants in the ground , I dig a hole about 6 foot across and two feet deep and fill with a good soil , then amend and cover with compost every season and it will just get better year after year . Your doing a great job and love seeing your posts 😎