About five years ago work started on a garden of old roses in the herb garden of the National Arboretum. Even by last year the plants had come to mature size and were extremely handsome.

This year I expect them to be splendid, well worth a visit. Holly Shimizu, curator of the herb garden (which you recall was paid for by the Herb Society of America), suggests the third week of May as a good time to see the roses, though they bloom over a period of some weeks.

My plant of the yellow rugosa rose 'Agnes' was at its height of bloom on May 7, for example, and a few other roses are on the early side, notably the red and yellow shrub rose Rosa foetida bicolor, which is usually gone by the time the great bulk of roses flower.

The arboretum garden displays a fully satisfactory assortment of the main classes of old-fashioned roses (most of them from the 19th century, so they are not all that old) in gallica, bourbon, damask, alba and other classes. The labels are eminently readable, assuming small children or gardeners have not made off with them recently, so that any gardener thinking vaguely of planting some of the no-longer-current roses in his garden can simply write down the names of those he admires and order them from nurseries.

I have a plant of the alba rose 'Celeste,' a soft fragrant pink, that is supposed to be budded on 'Dr. Huey,' but over the years the scion plant has apparently rooted, so there is now another 'Celeste' three feet away. Many of the old roses, on their own roots, will sucker, and some of the gallicas will spread over 20 feet in a few years from these suckers. Thus, such roses should either be budded plants (as virtually all nursery- grown roses are) or else a regular eye kept on the mother plant, to grub out any suckers that appear.

In the late Middle Ages, say the 1400s, gardens sometimes had very pretty wooden arbors, usually arched, and covered with roses. Since climbing roses were unknown in gardens then (apart from one or two wild kinds that I doubt anybody planted), the usual rose used for this purpose appears to have been Rosa alba (a garden rose, not the five-petaled wild progenitor).

The effect may be judged and admired at the arboretum garden, where such varieties as the pink 'Maiden's Blush' are used in this medieval way with great effect.

This may be the place to remind you that while the height of a rose bush may be given (in books and catalogues) as 3 to 4 feet, the plant may easily grow to 8 or 10 feet when tied in to supports and pruned to encourage upward growth. Thus many bush roses serve nicely as climbers of moderate height.

A rose of particular interest to me in that garden is the old noisette 'Champneys' Pink Cluster,' which was the first important American-bred rose, with the twin merits of perfume and constant blooming throughout the season. Its flowers are small, borne in clusters, and it is certainly not a rose for everybody -- for one thing it is a climber making a very large plant when happy.

But the genes of this rose introduced the quality of repeat blooming into the gardens of the West, and it is interesting on that score apart from its own charm. I think that almost my favorite rose is another noisette of about 1830, 'Jaune Desprez,' of soft buff flush with pink and powerfully scented. It is a vigorous climber, likely to be injured or perhaps even killed outright in cold winters, and the flowers are only a bit more than two inches in diameter, in large clusters opening for some days in succession. The color does not carry at all, and possibly most gardeners would want something brighter. But I mention it to suggest that the mere fact a rose is obscure in commerce does not mean it is worthless.

A number of growers -- most of them working on a small scale compared with the great commercial nurseries -- are raising and selling these roses that were unobtainable until quite recent years. The fine old firm of Bobbink and Atkins in New Jersey was a good source in the 1930s, before it went out of business, and I bought my first old roses there. I was going to tell you which one I got first and the name has gone out of my head. Try to avoid getting old and forgetting things. It will come to me at 2 a.m. and I'll phone you. Anyway, virtually every rose you ever heard of is still available from some nursery or other, so if there's one you have in mind and you're determined, don't give up.

I always wanted the mid-Victorian 'Blairi No. 2,' but for decades could not find a source. Finally bought it from Nick Webber on Havilland Mill Road. Mr. Blair introduced two roses, which he imaginatively called No. 1 and No. 2, then never introduced another. The second one was very popular as late as 1900. It gets black spot and blooms only in the spring and has this, that and the other wrong with it, no doubt, but it is marvelous, and God willing, mine will bloom next year.

In the meantime, I shall visit the arboretum old-rose collection. There they have plenty of money and manure and labor, combining to show how pretty these roses are when treated well.