PROPAGATING WOODLAND PLANTS
These are, of course, hardy perennials. Except for seeds, propagating methods are much the same as for cultivated types. It is important only that, if possible, you find out what is the most effective (often, the only) way each plant can be reproduced. If you can’t track down this information, try several ways at once. In general, those with masses of fibrous roots can be divided immediately after flowering. For upright and branching types, you can usually root stem cuttings in a frame or propagating box. If everything else fails, try layering. You can’t lose anything by it.
Seeds are planted the minute they are ripe, in a cold frame—or in flats that can be set in the cold frame—in a finely sifted mixture of equal parts of loam, woods leaf mold, and coarse sand. For varieties adapted to extremely acid soil, use half as much coarse sand as Michigan peat, without soil. For added insurance, acidify the planting mix with leaf mold or peat, or neutralize it with lime, until the pH is somewhere near that of the soil the plant grows naturally in.
Set the flats in shade and keep the soil moist, and leave the seeds to their own devices, summer and winter, until they germinate. Some species take two months, some take two years. After germination they are handled exactly like other perennial seedlings, except that the only safe fertilizer is very weak liquid manure at very infrequent intervals. Tender types should be grown in pots until they are fully mature, before they’re set out in the garden.