A CULTIVAR IS ONE BUSH, PROPAGATED BY CUTTINGS
The tea plant does not pollinate itself: its own pollen germinates, but fertilisation fails. Tea seed therefore always has an outside father, and a seedling never repeats its mother bush. A plantation grown from seed is not a cultivar but a mixed population in which every row is slightly different.
That is why every named cultivar exists only as cuttings. Yabukita was picked out in Shizuoka in 1908 from a single seedling; today it accounts for about three quarters of Japan’s tea acreage — millions of plants genetically identical to that one bush. Longjing 43 was made the same way: selected from a single plant, then taken forward by cuttings.
The practical part follows. When a packet names a cultivar, you get the same genotype every time, and the difference between years is weather and hands. When it says "old bushes" or "seed-grown", the bushes differ from each other as well, and nobody is promising the same cup next year.