Wallflowers (Cheiranthus).
This is a good biennial to start with, because every seed comes up and comes quickly. Sow thinly on a partly shaded patch of ground, and prick out when the seedlings have four good leaves. Do this on a showery day, if possible, and plant in rows ten inches apart each way. It is important to sow your seed early in the spring, because where the winter is severe the plants should be in their permanent quarters by May or June. If you transplant them late in the autumn, they suffer greatly from frost. In London market-gardens the seed is sown early in February; the plants are put out in May, and by Christmas are in flower. A seedling Wallflower has a tap-root as well as fibrous roots, and this is why the seedling should be pricked out once before it is transplanted to its permanent quarters. If you left it where it was sown it would send down a great root like a carrot, and then when you tried to move the plant you would kill it. Many gardeners pinch off the tap-root when they prick out, and then the Wallflower makes fibrous roots that can be safely transplanted. Mr. Robinson says that a well-grown Wallflower in a London market-garden could not be covered by a bushel basket, so now you know what size your plants ought to be, and how many you will have room for in your border. If you buy them ready-made late in the autumn, you will probably find that each plant has two bare, lanky stalks, with a miserable little bunch of leaves at the top; and when a frost comes they will look so dejected that you will pull them up and throw them away.