Always I am having to guard against too much yellow in the garden. It is easy to over-yellow the garden scheme in the spring, and again in the autumn there is a chance that the golden- flowered plants will be too overpowering. And if one isn’t very careful there will be too much yellow in July.
Most of the silver plants have yellow flowers. The buds of Seneci o greyii are as white as snow but they open to strong yellow, and a big bush of this senecio is very yellow when it is in full flower. Cutting off the flower-heads means cutting back the bush rather drastically, but that isn’t very serious for in a few weeks it will be bursting out of the bed again. But it will not look very pretty until it grows again, so a way out is to give it a nice green background so that it can flaunt its golden shower without upsetting the color balances. A background of Esphorbia mulfinii will calm it.
The helichrysums can get very yellow and again a lot can be done by careful planting. I have the airy-fairy H. plieatum perched at the side of the little crooked path, so that it grows over the low wall that holds up the path above the lawn. At the height of its flowering the bush is a mass of yellow, which I find almost too much so dose at hand. It is quite easy to cut off the flat, yellow heads on their long and slender stems, but it seems ungrateful to remove the result of a year’s effort When I am torn between humanity and aesthetics I wish I had a high rocky bank in which to plant this helichrysum. A friend of mine had a garden in Devonshire quarried out of solid rock, and this plant was perfectly placed in a pocket on that rock face which was draped with the evergreen Clematis armardii. It is a rather flimsy creature liable to be knocked about by wind or rough treatment, and the wall of rock gave it the protection it needed and the clematis toned down the dazzling display of gold.
That neat little bush H. trilineatum also has yellow flowers on every stem, but they are small and of a quiet tone; in fact they look like little clusters of old-gold plush and are short-stemmed so that they nestle in the bush and have the background of silver to temper their yellowness.
There are two helichrysums that smell strongly of curry. The one that is commonly known as the “curry plant” is H. angulosum and, as one can guess from the name, has fine silver foliage. The flowers are burnished gold rather than yellow and blend well with the leaves. The foliage of H. siculum is wider and pure white. It makes a big spreading bush and after the flat, yellow heads of flower are over tiny sprigs of flower open up the stalks.
Seneeio White Diamond has the whitest of white leaves—and the yellowest of yellow flowers, so when the dazzling white buds start to open they have to be removed. The flowers of Centaurea gymnocarpa are not yellow daisies but dirty-mauve thistles, so they have to be removed from the luxuriant fern-like leaves, of which they are quite unworthy.
The santolinas have sheaves of deep yellow button flowers and it takes a long time to cut them off. It is easier in the case of the compact S. incana than when S. neapolitana has to be shorn. This cotton lavender is the tallest and whitest. I keep two of its billowing mounds but prefer the ivory-flowered S. sulph-urea, which came to me years ago as an achilleal S. Lemon Queen has grey-green foliage and parchment-coloured flowers.
I thought I had found yet another santolina. I have a very large bush of S. neapolitana that has spread itself over several plants growing nearby I noticed one day that its flowers were lemon yellow, lemon yellow with a touch of green like an unripe lemon, and I was overjoyed at the sight. But my excitement was short lived, for when I investigated I found that the big S. neapolitana was sitting on top of a poor little plant of S. pinnata with green leaves and which, though flattened, was not going to be completely squashed and had thrust its flowers up among the silver foliage of S. neapolitana.
There are two santolinas with green leaves; the one I don’t grow because it has the yellowest of yellow flowers is S. viridis; the other, with its gree-ny-lemon flowers, is S. pinnata, and it makes luxuriant rounded bushes of evergreen foliage which spread attractively over the top of a wall.
Unfortunately, the best of the silver plants are not quite hardy that is as delicate as a fern and as white as anything in the garden. And to make it even more valuable the flowers are ivory and not yellow. Sensible gardeners don’t attempt to keep it through the winter but have a good supply of cuttings which they put out in the spring. There are two good ways to grow it. It makes a delightful effect if planted at the front of a raised bed where it will make a wide, horizontal plant by the end of the summer. For a prominent place this silver plant looks well with pink ivy-leaved geraniums or plumbago, which give color all through the season.
Not being a sensible gardener, I grow my senecio against a south wall in the hope that it will go through the winter—and sometimes it does. Not realising how rampant it could become I planted the climbing groundsel Senedo scandens near the silver groundsel and it does give it protection, although it almost smothers it.
I fell in love With Attend:la arborescens in an Irish garden where it was growing in a bed about six feet from the ground and hanging over the wall. It was summer and the artetnisia was in flower, typical artemisia flowers, so that it looked like a miniature mimosa frothing over that grey stone wall. I begged a cutting and have managed to keep it ever since by cosseting the cuttings in the winter. It has the most delicate foliage I know and makes it.