Latitude first
Latitude sets the length of the growing season, and the growing season sets almost everything else.
Xinyang（信阳）in Henan sits near 32°N and its bushes stop for the winter. Dian green tea from Yunnan sits near 25°N and never really does.
Resting for months lets a bush put its stored reserves into one short spring flush, and that is where the thick sweetness of a northern green tea comes from.
A bush that never rests grows continuously and gets picked continuously, which produces more leaf with less in it.
This is why southern green tea is often cheaper and often needs more leaf per cup to taste like much.
Latitude also decides winter survival, which is why the northern limit of tea in China runs where it does and not further.
Rizhao（日照）in Shandong is the usual example of how far north the bush can be pushed, and the leaf there grows thick and slow.
Shelter and selection can push it further, but the season eventually gets too short for the harvest to pay for the winter.
Then elevation
Within a latitude, elevation does the fine work.
A garden at 200 m and a garden at 1,000 m in the same county can pick weeks apart, and the high one will usually produce a slower, thicker leaf.
Cool nights slow respiration, so the compounds the leaf made during the day stay in it rather than being burned off.
Cloud also matters. Diffuse light at height produces a different balance of amino acids to catechins than direct sun does.
The result in the cup is usually more sweetness and less bite, which is what people mean when they call a mountain tea soft.
Elevation is not free, though. High gardens are small, hard to work, and pick later, so the tea costs more before it is any good.
Rain matters as much as temperature here, and a wet high garden gives a different leaf from a dry one at the same height.
Two counties at identical elevation can produce nothing alike if one of them sits in cloud and the other in open sun.
Then the cultivar
The third variable is the plant, and it is the one that most buyers never see.
Longjing 43（龙井43）is a selected clone that leafs early, holds a flat shape and gives a mild cup. It is planted far beyond Zhejiang.
Local seed populations, often called qunti（群体种）, leaf later and less evenly, and they taste more particular.
Fuding Dabai（福鼎大白）is a Fujian cultivar planted across several provinces because it yields well and handles being made into many shapes.
Anji white tea is not a white tea at all but a temperature-sensitive green cultivar that loses chlorophyll in cold springs.
Two teas made on the same day in the same county from two of these plants will not taste like each other, and no amount of terroir talk changes that.
The plant also sets what shape the leaf can be pressed into, which is why some cultivars end up flat and others end up curled.
A grower who bought the wrong clone for the local climate spends every season fighting it, and the cup shows the strain.
Reading a label
So read a label in that order: where, how high, and what plant.
Most labels give you the first and hide the other two.
If a seller can tell you the cultivar, they almost certainly know the garden, and that is a better signal than any certification mark.
If they can only repeat the region name, assume the cheapest cultivar that grows there.
And when two teas from the same region taste nothing alike, the plant is usually the reason before the soil is.
Region narrows the field. Cultivar and elevation pick the tea.
None of this needs specialist equipment to work out, and it does not require trusting a certificate either.
It requires a seller who answers three plain questions instead of repeating the name of a mountain.
Keep a note of what you liked and what you did not, and the pattern will show up within a handful of purchases.
Most people end up preferring one latitude and one style, and learning which is worth more than memorising regions.