Clematis are notoriously heavy feeders and require rich, organic soil for robust growth. Although slow to start, once established, the Clematis will provide years of enjoyment and bloom. They need cool roots, which means that there has to be something growing on the soil in front of them or the soil should be covered with stone or mulch. Clematis vary as to whether they should be pruned back hard. Some bloom on the new growth and some bloom on the vines from the year before. Make sure you know which type you have! They do not like acidic soil, so if you have added a lot of peat moss you will need to add lime as well.