Does tea trees have sex? By sex, it refers to whether a tea tree blooms and produces seeds. Get your mind out of the gutter!
Some trees produce flowers and seeds and some don't, especially the older trees (century years old) that live in ideal environment. This phenomenon also exist in human race. The more educated people are less likely to have more kids if any at all. Theoretically, these are the people with the right genes and means to carry on human race. Ironic, isn't it!
Among ranges of phoenix mountain, high altitude century old trees survived for hundreds years without producing any seeds. Hence unique with its own flavors as single bushes, different from the tree next to it. For this very reason, it's a significant lost once a tree dies. The natural habitat of these century old trees are shielded from decease, the climate is ideal for their longevity. Cause of death of old trees are usually man made, chopped down by human. Ever since cloning method was used to plant small trees from branches, these unique old trees can be "preserved" with their legacy flavors.
One may ask, how come clones from the same tree can bloom and produce seeds? It's nothing more than the law of nature - specie survival. When the livelihood of the tree is threaten by nature, such as lack of nutrition/water/nourishment, harsh weather, the survival mechanism kicks in, it will start blooming, massively producing seeds, ensuring the birth of next generations in case the mother tree can not survive. Trees that blooms are usually abandoned hill side farms in lower altitudes facing west. Well, perhaps in a couple of hundred years, any trees still alive at that time will become the most sought after flavors.