When you buy a tea blend, much effort might have gone into providing a tea with a stable flavor profile from year to year. The teas that go into the blend sometimes come from different harvests and farms, and also from different countries. When you buy a major label brand tea, for example, the tea blenders know that you want to have the same taste experience from year to year. They take great pains to blend a tea that will provide this for you.
Contrarily, many tea connoisseurs value teas that are not blended, but come from one particular harvest, which means they come from the same country and farm as well. Teas such as this can change in taste pretty dramatically, not only from season to season, but even from one day's harvest to the next. What is offered from season to season and harvest to harvest has its own characteristics that
cannot be duplicated, and for some of us, that is the point!
If you are such a tea person, you might be searching for "single estate" teas. These are teas that come from one tea garden. The tea may come from different harvests (generally in the same season) , but the tea in your bag comes from the same farm. It is also possible to find "single harvest teas", which come from a particular day's picking. Tasting a tea that is plucked on Thursday will necessarily taste slightly different than the tea that is plucked on Saturday. It is quite educational to have the opportunity to taste teas plucked and processed on different days. They can be dramatically different in character, even when processed by the same farmer or tea master.
Then, there are "single trunk" or "single bush" teas. These are teas that often come from older, more mature, and "famous" tea trees, particularly Wuyi teas or Puerh teas coming from "ancient trees" in Yunnan, where tea originated. In this case the tea in your bag comes from just one tree or bush. This is rare, indeed, and of course, the harvest from just one tree or bush will provide just a small amount of tea and so is more rare and difficult to obtain.
As a tea seller, I have had the opportunity to try teas from one harvest to the next, and the effort to buy the same tea twice can be frustrating. It has happened, for example, that I try to buy more of a harvest only to receive several pounds of tea that is a pale cousin to the tea I have been selling. In this case, I often have to eat the cost of my purchase. Even though the tea might be from the same farm and the same season, it is not at all the same tea, and my own standards won't allow me to sell a tea that I don't wholeheartedly believe in.
Thanks for your feedback, which keeps me alert not only to great new harvests but careful of teas that, while coming from the same farm and the same season, might not be the same harvest and therefore not quite make the cut.