When we first built our house, we took our parents to the local plant nursery to buy some herbs for a small area of the farm. We planted four small basil trees in a hard clay soil. At first they didnt grow much. Then after 2 months they started to reach up and grow wider. As of today they are over 1 meter tall and nearly a meter wide.
The basil tree flowers constantly little bluish/purple flower on a long stem. It has a wonderful basil smell and attracts ALOT of pollinators to our yard. Their seeds drop into the garden bed meaning we have a constant supply of basil for thai dishes.
I use two methods for growing basil trees. By seed or by cuttings. Seed is easy enough, sprinkle roughly 5-6 seeds into a 50 or 104 pot seed tray and cover lightly with potting mix. You should see germination in 14-21 days. They start off as very small sprouts and should be grow under shade till they have a leaf size of 1-2cm.
I have repotted the last set of seedlings that are going well. The second option is to take cuttings and place them in damp soil. Keep under low light till they start to take root.
Basil trees also act as a great refuge for our chickens. We have had numerous hawk attacks. When a hawk is spotted the young bantams run to the basil tree to take cover. They can also be trimmed into a hedge around your garden.