I have been weeding the low planting around the garden railway. Prostrate thyme, Thymus serpyllum, plays a large part. In autumn and winter after it has been cut back it can look a bit stark, but at this time of year it is covered in small purple flowers and is very attractive to bees. It is happy growing in the light soil, and seeds itself about moderately, which is useful for filling in the gaps.
Named varieties are available, but ours was grown from seed. If the seedlings are pricked out into modules, twenty-four to a standard seed tray, then once well rooted the plug can be planted successfully straight into the gravel, without further potting on. This is a great saver in time and greenhouse space. In fact, given thyme's preference for perfect drainage, the sooner it goes into the gravel and the less time it spends in a pot the better.
The plants are not awfully good at suppressing weeds, it has to be admitted. They are not dense enough, and seedlings of grass, wild vetch, field maple, and the little yellow flowered annual member of the pea family whose name I have still not discovered, will all germinate under the thin cover of thyme and pop up into view. Two or three years ago I was getting quite disheartened about the prospects of ever getting the weeds in the railway garden under control, but after a fairly concerted effort at weeding over several years there are not so many this year. Much less grass, certainly, though I am afraid I have let rather a lot of wild vetch go to seed and will be pulling their babies out like mad next season.
To thicken up the carpet, and provide some variety, I've been planting low sedum among the thymes. The best and toughest on our extremely light soil has proved Sedum album 'Coral Carpet' which forms gradually expanding mats of densely packed, tiny, fleshy, leaves in a pleasant shade of purplish pink. It is wonderfully easy to propagate, simply pull little pieces from the edges of your established clumps and dibble them into divided trays of well drained compost. A few months later you will have plugs ready to go out like the thyme plants, straight into the gravel. Short cuttings of the dwarf stemmed varieties like 'Vera Jameson' strike very easily too, though the plants don't cope with the sand as well as 'Coral Carpet'.
I have unfortunately lost the name of one splendid, red leaved, low growing, stem forming variety. Pots of it adorn the top of a low wall, along with pots of houseleeks, and I keep adding more plants to the gravel planting where it grows pretty well, but my original plants were used for the failed experiment in making a green roof for the pot shed, and while I salvaged the plants and propagated more from them after dismantling the roof, I failed to keep a note of the name. It has deep pink flowers to go with its red leaves, and is a really useful variety, and I wish I knew what it was. It is probably not especially rare, and if I were to ask somebody like the Plant Heritage national collection holder for sedum they would probably know what it was, but so far fortune has not brought a specialist in sedums my way.
Sedum rupestre 'Angelina' does well too. It has long, ochre yellow leaves and yellow flowers, and roots easily from cuttings. It is a brittle plant, and out in the garden I tend to poke any pieces that fall off straight back into the gravel. If you were a very restrained and tasteful gardener you might think it was too yellow, but I like it in small splashes. Little dabs of it give all that purple a lift. I wouldn't plant a large continuous sheet of it.
The grey, hairy leaved shrub Lotus hirsutus loves the gravel a lot. It was originally in the long flower bed, and still is, but its offspring have been eagerly colonising beyond the border since the gravel was put down. This afternoon I was hard-heartedly weeding tiny ones out of what is supposed to be the path running the length of the railway, otherwise the entire layout could disappear in a Hairy Canary Clover forest, given a few years.