It is surprising how constantly we require to be learning. It seems that while we are ever learning, we are, at the same time, ever forgetting; and while, on the whole, we may be adding to our stock of knowledge in the aggregate, our mental notes are filed and forgotten, until now and then the eye or ear, like an index to a good book, suddenly prompts the mind that its notes can be utilised to some immediate purpose. It is hard work to think; and we may even see and not observe, consequently we slide along in an old groove, and allow others to think for us: an occasional jerk of shame, necessity, or interest is a wholesome stimulus to action. We have lately been aroused to a sense of our own short-sightedness while comparing the doings of a neighbour with our own, in the matter of hardy plants which might be used for edging or carpeting. In looking round a well-stocked wild garden, which, however, is a rarity; or a richly-planted rockery, which is rarer still - the rockery at the Botanic Gardens, Edinburgh, for instance, - a monument to the maker, and a book of reference to those within its reach - it is surprising how many plants are clearly suitable for edging or carpeting permanently, or changing annually if desired.

Many of them may be poor things, so far as showy flowers are concerned, but form and habit are equally or more essential for the purpose, and, happily, form and habit are becoming equally appreciated with colour. We wish to draw attention to a few of which we have some experience, - and first to some of the neglected Sedums. There are several which have become quite familiar to most people, of the very small S. acre type, such as S. acre aurea and S. acre elegans; also S. glaucum, lydium, dasyphyllum, and corsicum. But there are others equally deserving of culture, and the foremost is surely Sedum album, a dense-growing, reddish-green species; but its beauty is in the flowers - it is quite a flowering plant for edgings. Last summer it lasted a long time on the rockery and in borders; and many yards on the top of a high wall here were quite gay with its elegant flowers, but did not last so long as those on the ground. We intend pressing this into the flower-garden service next summer. Another bold-growing glaucous sort is at present in better condition than it has been all the summer - namely, monstrosum, elegans, or Fosterianum. It sometimes grows with the ends of the shoots fasciated, so called monstrosum.

Whichever is the right name, it is a very desirable plant in the mass, does not flower very freely, the spikes large and heavy, yellow, and best pinched off as they appear. Sedum anacampseros is a really elegant species, with round glaucous leaves, not unlike a small Echeveria secunda glauca. The stems lie prostrate on the ground like other Sedums, but the little pyramidal ends of the shoots are always erect. There is a large sheet of it hanging over a large rockery-stone here, and it is novel and elegant. It is a plant as old as any English garden. We have propagated several hundreds of it by nipping off the leafy points of the shoots and inserting them in prepared ground, and shall give it a place in the flower-beds next year. Sedum acre aureum is now being used to carpet beds of Hyacinths and Tulips, and we expect in the spring that the arrangement will look well. This has a tendency to turn off green on rich soil, when it fast becomes an intolerable weed. It keeps colour best when made to creep and hang over stones. Another of those Sedums, and we have done with them - Sedum spurium or oppositi-folium, we are not sure. It forms a close dense mass of green, close on the ground, the leaves broad and fleshy. There are three varieties growing on blocks, stones, and the open border here.

One variety is the best in colour - a dark-red; the other two are white and rose-colour, the flowers large. This Sedum will make a very desirable change among hardy carpet-plants; even the flowers are showy hanging over a large stone. A few hundreds put in to propagate last month in nursery lines have become quite red in the foliage, as the small Sedum lydium does under a hot sun. There are three of the Periwinkles, which are very neat for permanent edgings to beds - namely, Vinca herbacea, V. minor, and V. minor variegata - the latter a very choice plant, though all are sometimes found carpeting the ground in woods. The variegated variety is a good substitute for Euonymus radicans variegata, which requires rather a warm soil and climate to bring out its character. The Vinca thrives anywhere in sun or shade, creeping over the rockery or in the open border. The double-flowering variety of the green V. minor is desirable even for its flowers, although they, from their colour, cannot be called showy against the dark-green foliage.

Few plants surpass the Ivies for permanent edgings, especially the small - leaved varieties and the gold - and - silver margined, although these last take a longer time to grow and fill up space than the green varieties. As compared with Box for kitchen-garden edgings, we are not sure whether Ivy would not be for the best on some soils where Box does not thrive. For edging flower-beds, the best plan by far is to stretch a strong wire tightly along the edge of the bed or border to be edged, if a straight line; but if curved, a light iron rod bent to the proper curvature on which to train the Ivy. Three or four inches, or six inches above the ground, according to taste or position, will do - the latter height for Roses, the shorter height for flower-beds. Plant thickly and train cordon fashion, and very soon a neat permanent edging is formed, the young side - growths of the Ivy drooping gracefully to the ground; and soon the wire is completely hid, but maintains the edging stiff and straight.

The next plant we will mention may occasion a smile; but we cannot help calling attention to its merits, since its very commonness may cause it to be passed by. Lysimachia nummularia is a plant often used for edging vases, notably at one of the Park Lane gates of Hyde Park many years ago. Its large showy yellow flowers have been very abundant the whole of the last wet summer. It is particularly deserving of a place as a variety in edging any dwarf arrangement, especially in moist shady places, such being the localities where it is found wild. Sagina procumbens is a very common plant or weed, carpeting the ground when not wanted; but common though it be, there is no plant which will form a neater, or greener, or more dense carpet than this. We have this season seen it worked into several very neat designs in carpet-bedding in a first-class garden, and again in a villa garden near Edinburgh. It really seems to deserve a place in preference to such a plant as Herniaria glabra, or even the tender Mentha gibraltarica.

Readers will probably here be inclined to say that we are simply introducing weeds into the flower-garden; but we may fairly ask the question, What is a weed 1 Is a common indigenous plant a weed, or is it, as the late Earl Russell once defined it, any plant out of place?

The Squire's Gardener.