Summer's heat is lingering on, but there are hints in the air that the glorious days of autumn are just around the corner. Fall in Japan is exciting for its famed tree foliage, but the weather is also perfect for gardening -- or for visiting parks during your lunch break or on days off.

A couple of days ago, when I visited the Hattori Ryokuchi Arboretum in Osaka, I was reminded of one of gardening's often unsung delights, whatever the season -- namely that to be derived from members of the grass family (Gramineae) -- though not its best-known members here, which are bamboo and rice.

Anyone lucky enough to have a garden has a wide choice of grasses to grow, either ornamentally or in lawns, while balcony gardeners can beautifully enhance their mini-oasis with some very nice types. At the Osaka arboretum, however, what really caught my eye were the large stands of pampas grasses, which looked just magnificent.

Pampas grass (Cortaderia selloana), not surprisingly, comes from the Pampas, the treeless South American plains most closely associated with Argentina, but which extend into Brazil and Chile. Popular with gardeners, pampas grass grows to a height of 3 meters, with long, thin, arching leaves that have extremely sharp margins. The plumes, in colors ranging from silver-white to pale rose to golden, are at their best in early autumn, with the male and the showier female flowers borne on separate plants.

If a 3-meter plant seems a bit too much to consider for your balcony, some pampas grass cultivars, such as C. selloana "Bertinii," are true miniatures that grow to no more than 1 meter and look very nice in a large earthenware pot. Growing around 20 cm taller than that, the cultivar C. selloana "Silver cornet" has cream-striped leaves, while C. selloana "Pumila" is also very compact as well as being especially floriferous.

All pampas grasses are clump-forming perennials, and if yours are growing in open ground, the best way to keep their size under control is by burning them back just before winter sets in. If you are growing them in containers, on the other hand, cut them back by hand -- but remember those nastily sharp-edged leaves.

Recently in Japan it has become a trend to grow grasses both native and foreign. Beni-chigaya (Imperta cylindrica "Rubra") is a very attractive native perennial cultivar with dark, wine-colored leaves that is considered by gardeners to be one of the most striking of all small ornamental grasses. Chigaya, the parent species of beni-chigaya, is a clump-forming grass whose stems are used for thatching. In its native habitats in Japan, Korea and China, chigaya grows in colonies in open places on low mountains.

In contrast, beni-chigaya will grow in sun or semishade and can tolerate temperatures as low as 15 degrees, making it an option even for Tohoku residents. The leaves are flat and upright, reaching 20-50 cm in height and 7-12 mm wide, and its inflorescence (flower cluster on a common axis) is 30-80 cm long with silvery, erect panicles of spikelets each 3.5-4 cm long and bearing tufts of silvery hairs.

Another beautiful native Japanese grass is urahagusa, also known as fuchiso (Japanese forest grass; Hakonechloa macra). This clump-forming perennial with bamboolike foliage has a creeping rhizome, and in winter the upper part of the plant -- which can reach to 80 cm with graceful, arching stems -- dies back. Urahagusa is endemic to Japan, and in its natural habitat it is found on shaded wet cliffs on the Kii Peninsula and similar areas in the Tokaido region. Flowers are in short panicles, 5-15 cm long, that are borne between August and October.

In place of this native green species, though, two cultivars of urahagusa are more popular with gardeners, and both make ideal pot plants. Kin-urahagusa (H. macra "Aureola") has beautiful leaves with golden margins and a thin green strip in the center; while its H. marca "Alboaurea" variant has golden- and green-striped leaves. In a small garden, plant urahagusa in front of a shaded border or under a small tree in a position where people can easily admire the beautiful summer foliage.

Still with native plants, though not grasses anymore, the variegated Oshima-kansuge (Japanese sedge; Carex oshimensis), which will slightly tolerate drier conditions, has grasslike foliage that grows up to 40 cm high with 4 mm wide leaves whose edges are soft to the touch. The species is an evergreen perennial native to Izu Oshima.

"Evergold," one of its most popular garden cultivars, has golden- and green-striped foliage and is very attractive when grown in pots or small gardens along with with other perennials such as hosta -- the only requirement being that it is in a leaf-rich soil.

Altogether, the sedge family (Cyperaceae), known as kayatsuri-gusaka in Japanese, is represented in this country by more than 200 species, making it hardly any wonder that botanists sometimes differ over the names of particular plants.

One that is extremely well-known and virtually impossible to confuse, though, is susuki (Eulalia grass; Miscanthus sinensis), a native of low-lying areas of Japan that, along with the pampas grass, was in particularly fine form at the Osaka arboretum the other day, growing up to 1-2.5 meters high.

The susuki's silvery-gold, 15-30 cm long plumes that are borne atop long thin stems from now until November are taken to signal the beginning of autumn. Those stems, too, are also used for traditional thatching, as well as to make nari-mono flutes used in sacred Shinto music and in kagura dancing.

On the down side, the leaf margins of susuki, like those of the pampas grass, are very sharp. When planting or cutting back in winter use strong leather gloves and wear a long-sleeved shirt, as even a small cut from this plant can be very painful.

There are numerous lovely cultivars of susuki that are grown in gardens around the world, including M. sinensis "Variegatus," which has white variegation running the length of the leaf. One of my favorites is takanoha-susuki (tiger grass; M. sinensis "Zebrinus") an old variety that dates back to 1877. Its common English name derives from the fact that toward the end of summer, bands of yellow appear on the leaves. Its feathery, pinkish-brown plumes, produced from August till November, are also often seen in flower arrangements.

Finally, susuki is one of the traditional aki-no-nanakusa (Seven Flowers of Autumn), of which the other six are kuzu (kudzu vine; Pueraria lobata), which is, unfortunately, too vigorous for most gardens; kikyo (balloon flower; Platycodon grandiflora); fuji-bakama (Eupatorium fortunei); nadeshiko (pink; Dianthus superbus); hagi (bush clover; Lespedeza thunbergii); and ominaeshi (Patrinia scabiosaefolia). When visiting parks this autumn, see how many of the seasonal seven you can find.