Terra cotta pots keep the soil well drained, but they are also heavy and likely to crack during the winter until kept indoors. Stone pots can last through a variety of temperatures, but they are often even heavier than clay pots. Plastic pots do not drain water quite as well, but they are light and fairly durable. Containers made of treated wood offer a good balance between durability, weight, and drainage, especially if they have an inner lining made of tin designed to preserve the wood longer.
You can find most of these materials at a garden supply store, but if you are unable to locate them, you can also collect stones from a nearby creek or use a hammer to break an old clay pot into pieces. If collecting these materials from nature, though, you should sterilize them by soaking them in hot soapy water, or in a solution made with one part bleach and four parts water.
The label “10-20-10” refers to the percentages of nitrogen, phosphorus, and potassium. Nitrogen produces leaves, phosphorus strengthens the roots, and potassium helps flower growth. The fertilizer you choose should be balanced in nitrogen and potassium with a slightly higher content of phosphorus.
For clematis that bloom early on the previous year’s growth, you should remove all the dead and weak stems as soon as the plant flowers. For clematis that bloom between mid and late summer on old and new growth you should only remove dead growth once the plant gets crowded. For clematis that bloom between mid and late summer on new growth alone, you should remove all growth from the previous year, only leaving the lowest pair of buds.
