is an enzyme a living organism
An enzyme is a protein. If you are asking if an enzyme could be considered to be an independent living organism... generally no. However, a bit of artistic interpretation of the seven signs of life (listed below) could lead one to interpret some enzymes as independent living organisms.
If you have a shrub-form crapemyrtle, simply shape it as desired. Remember that it grows vigorously in summer. If you want it to be six feet high, prune back to 4 – 5 feet in winter to allow for new growth. And here’s a link to a study of how pruning affects the growth and blooming of crapemyrtles.