Despite being something of an acquired taste, toon tree leaves bring the taste of spring to the table

We have a couple of trees at the bottom of our garden that never seem to grow very tall, or broad. That's because they get a very hard trimming in spring each year when the sap finally flows and they put out tender bunches of maroon-colored shoots.

These are our precious Chinese toon trees, and our nanny watches them like a hawk every year when shoots bud along the nodes for just a few short weeks.

If they are not harvested in time, they all disappear overnight, to enrich the dining table of someone else.

Toon is probably the only tree vegetable in China, and its leaves are pungent and definitely an acquired taste. You can say it is the litmus test for the adventurous foreign gourmet, along with century eggs, stinky tofu and Beijing bean juice.

From north to south, the red shoots herald the arrival of spring and mark the beginning of the growing season. Its Chinese name, xiangchun, literally means the "fragrance of spring". Although it is horticulturally Chinese in origin it has spread to many countries, including the United States and Europe.

My husband remembers seeing avenues of toon trees in Washington DC when he was a foreign correspondent there. I remember toon trees in Brussels, a stone's throw from the EU headquarters.

My introduction to eating toon shoots was memorable.

As a new daughter-in-law arriving in Beijing I had my first taste of toon leaves at my mother-in-law's courtyard home in the hutong. The shoots came from a tree behind the house which my brother-in-law had deftly clambered up and harvested.

His wife had then blanched the leaves, chopped them up and served it with a cold tofu salad. My mother-in-law noted I was looking at the pile of green and white dubiously and had patted my hand.

"Try a little. If you don't like it, don't eat it."

I loved it. The strange pungency of the leaves was addictive. It was a mixture of raw onions and garlic, but strangely subtle and really hard to define.

Eaten with cold mashed tofu, the leaves were slightly crunchy and had just a little bite to them. The tiny bits of stalks added a tactile contrast with the tofu.

I have since eaten many. I have also learnt to fry up toon leaves tempura, and flip a mean toon omelet.

To the Chinese, the toon tree makes its presence felt in the early days of spring and that first taste of the pungent leaves in an omelet or simply tossed in a salad with tender tofu is confirmation that the long bitter winter is really over.

Food is symbolic in China, and certain foods must be eaten at certain months or in certain seasons, and this is a faithfully kept tradition.

This has been how our ancestors ate, and we still continue cooking with one eye on the farmer's almanac. Spring greens from the good earth is one way of cleansing palates dulled by a winter diet dominated by pickles and preserves.

In the good old days, toon trees were everywhere. China's warp-speed urbanization means the jungles are now concrete with carefully cultivated patches of decorative green, and toon trees are now rare in the cities.

Fortunately, rural farmers have seized upon the commercial opportunity of satisfying city dwellers in their annual craving for toon. Improved logistics also mean that warmer climes in the south are freighting toon shoots to the north, at premium prices.

The even more enterprising have taken to sprouting toon seedlings out of season, much like alfalfa sprouts. These are beloved by modern Chinese chefs who adorn their fusion creations with these micro sprigs of green.

Whether greenhouse sprouts or naturally grown shoots freshly plucked from trees, the Chinese toon is one unique ingredient.