In these days of year-round growing of vegetables in temperature-controlled conditions and air shipments of fresh produce from around the world, it's all too easy to forget the seasons. But in Japan, seasonality is still highly treasured, and there's no time like the spring to enjoy certain vegetables that are only available for a short time.

Japanese spring vegetables (clockwise from top): Yama udo, no me, fuki no zenmai, nanohana and takenoko. Many of these delicacies can be found only in Japan and only in springtime. MAKIKO ITOH

You'll see vegetables that are familiar to the Western palate, such as green asparagus, watercress, sora-mame (fava beans or broad beans) and green peas. There are also spring versions of sturdy year-round produce to enjoy, like tiny new potatoes and sweet spring cabbage. You may already be familiar with quintessential Japanese vegetables such as gobō (burdock root) and takenoko (bamboo shoots) — the ones gathered in the spring are particularly fresh and tender.

Joining these on the shelves of greengrocers for a short time in spring are several vegetables commonly known as sansai, or mountain vegetables. Many bear names for which there are no straightforward English translations: seri, tsukushi, fuki, tara no me and yama udo (more on these later).

While some sansai are cultivated these days, connoisseurs prefer the stronger bitterness of sansai gathered in the wild. Sansai went out of vogue for a while, but with the recent interest in health and "natural living" they've made a big comeback. Their bitter, even tannic quality is believed to have a salutary effect on the body, especially after a winter of stodgy food. According to folklore, bears waking up after their winter hibernation nibble on sansai to get their digestive systems going. Most sansai are also rich in vitamins and minerals as well as fiber.

If you're lucky, a neighbor may have gone sansai hunting in the countryside and come back with bounty to share. Sansai gathering used to be something only your grandmother bothered to do, but now hip urbanites go on organized gathering trips in the mountains on weekends. If you're interested in collecting your own sansai, make sure you go with an experienced guide at least for the first time. Just as with mushroom picking in the fall, there is the danger of mistaking a poisonous plant for an edible delicacy.

One caveat regarding sansai: It may not be advisable to eat the more bitter kinds in excess. Like certain medicinal herbs, too much of a good thing may lead to unfortunate side effects such as diarrhea or stomachache. In small quantities as part of a meal, they are fine, and a great way to savor springtime before the heat of the summer comes upon us.

Let's look at ways to prepare and enjoy some popular or unusual spring vegetables, starting with takenoko. While you can purchase precooked or canned bamboo shoots all year round, in spring you can find ones that have just been dug up from the ground. Fresh takenoko are usually sold with a little packet of nuka (rice bran). Peel off the dark skin of the takenoko until you get down to the pale beige part. Put the nuka in a pot of boiling water and add the takenoko; simmer for 20 to 30 minutes. (If you didn't get any nuka, you can also use the cloudy white water produced when rinsing rice instead.) Turn the heat off and let the takenoko rest in the water until cooled. Rinse well and cut up to use in tempura or in nimono (stewed dishes), cooked with rice, and so on.

Gentle kick: Wasabina or hawasabi, the tender leaves of the wasabi plant.

Fuki no tō are the sprouts of the fuki plant: Peel off the outside stem-end parts (called the hakama, or "pants") plus any discolored bits. The sprouts can then be stewed in a mix of dashi stock, soy sauce, mirin and sugar, or turned into tempura (see recipe). The stems of the grown fuki plant are also eaten: Peel off the stringy outer parts, and stew as with the sprouts or blanch and marinate for a day or more in a miso, mirin and sugar base with a chili pepper added for a little spice.

Tara no me are the young offshoots of a tara tree, part of the aralia family. Most of the tara no me you can buy in stores these days are cultivated and are only mildly bitter. Take off the hakama as with fuki no tō, clean and use in tempura, blanched and served with soy sauce and bonito flakes, sauteed and so on.

Yama udo are offshoots of the udo tree, also from the aralia family, that are grown in the dark or with the earth mounded around them to blanch them, like white asparagus. Peel off and discard the tough, hairy outer skin, then peel the hard outer part of the white stem, leaving the tender core. Both parts should be soaked in water, with a little vinegar added, for 30 minutes to reduce the bitterness. Julienne the outer part and saute in sesame or olive oil; slice the core thinly and use raw in salads.

Warabi, or fiddlehead fern shoots, should be prepped by pouring boiling hot water over them and adding a pinch of bicarbonate of soda or wood ash. Leave to soak until the water is cool, then rinse and use in miso soup, salads and so on.

Wasabina or hawasabi are the young leaves of the wasabi plant. They have a mild wasabi taste and only need to be blanched for a few seconds, cooled and served with dashi stock and soy sauce. You can also saute them briefly in butter or olive oil, with a little chopped garlic, and serve them over hot pasta for a special treat.

Ki no me (which literally means "tree buds") are the tender young leaves of the sanshō pepper tree. Grind up the leaves to sprinkle as a condiment, or just use a small sprig as a garnish.

Recipe for spring vegetable tempura Tempura is a great way to enjoy many spring vegetables without a lot of fuss. Deep-frying takes the edge off any bitterness, without the need for parboiling and so on. Here I've fried up some tara no me, fuki no tō, young gobō and seri. Serve with a little bit of salt to let the vegetable flavors shine though. Besides sea salt, you can find colorful matcha salt, yuzu salt, lemon salt, sakura salt and so on for sale in department-store food halls and better supermarkets. Serves 4 as part of a Japanese meal Seri, cut into 15-cm-long pieces — 1 small bunch Gobō (burdock root) cut into fine julienne — 1 15-cm piece Fuki no tō — 15 to 20, bottoms trimmed Tara no me e_SEmD 15 to 20, bottoms trimmed Tempura flour or all-purpose flour — 110 g (about ¾ cup) Potato starch or cornstarch (only if you're using all-purpose flour) — 2 tbsp Large egg — 1 Ice water — 500 ml (2 cups) Oil for deep frying, such as natane (canola/rapeseed) oil, peanut oil or "tempura oil" Sea salt or special flavored salt as desired The vegetables should be perfectly dry on the surface to ensure a crispy finish. Pat the washed and prepped vegetables dry with kitchen towels, or leave them out in a single layer on a sieve or basket until they have dried out completely. It's fine if they wilt a bit as they dry. Put the vegetables into a large plastic bag with one-third of the flour (if using all-purpose flour and potato or cornstarch, mix together beforehand). Close the mouth of the bag and shake to coat the vegetables. Remove the vegetables, shaking off any excess flour. In a large bowl, beat the egg and add about two-thirds of the ice water. Add the flour and mix lightly with a whisk or cooking chopsticks. Don't worry about any flour lumps or unmelted ice cubes; if you mix the batter too much, the tempura will become doughy. The batter should resemble thin unbeaten cream: If it looks too thick, add a bit more water; if too thin, a bit more flour. Prepare a large plate or tray lined with newspaper, with a layer of paper towel on top, to drain the tempura. Fill a pot or wok no more than 1/3 with oil. Heat until quite hot: If you are using a thermometer, the temperature should be at least 175e_SDgr Celsius. These tender vegetables cook very quickly, so should need no more than 30 seconds or so per side. Start with the fuki no tō, dipped and turned in the batter then into the oil one by one. Follow with the tara no me, also fried individually. Finally, toss together the seri leaves and gobō, and fry in small clusters. Do not overcrowd the pan at any time, and drain the cooked vegetables immediately. Serve while piping hot and crisp, with a small mound of salt on the side of each plate.