Provided with the appropriate growing conditions and adequate care, clematis will bloom profusely in summer, making this vine a showy specimen, perfect for growing on trellises, fences, walls, mailboxes and other types of supports.
Evaluate Soil Conditions First...
Because most varieties of Clematis thrive in a wide range of soil pH (6.0-8.0), there's usually not a need to perform a soil test before planting or fertilizing them; however, it may be a good idea to research the various varieties of Clematis you have growing in your garden to see if there are any specific nutritional needs for specific types of perennial plants. Too, your soil may be way out of range and a soil test will indicate such. You can use the Gardenality Search to find Clematis Plant Files on which will you will find the soil pH requirements and other details. Simply type one word in the name of a plant into the search at the top of this page and a list of plants files will appear. For example: If you are looking for Jackmanii Clematis type the word "Jackmanii" or "Clematis" in the search to find the plant.
To test your soil, you can purchase a test kit at your local nursery and garden center or buy a soil test kit online here. Your local extension service might also provide soil testing services.
Feeding Clematis
Clematis are a little slow to establish themselves after planting. Given the proper care clematis will strongly establish themselves and thrive for many years to come.
Clematis is at its best in rich soils with good drainage and prefers a neutral to slightly alkaline soil, so first check pH and add lime if needed to sweeten the soil. Soil test kits are available at most nursery and garden centers or you can have your local extension service test for you. Keep in mind that clematis is a heavy feeder. You'll want to supply a low nitrogen fertilizer such as 5-10-10 in spring, when the buds are about 2 inches long. Then feed every 4 to 6 weeks with a balanced 10-10-10 fertilizer. Continue this alternate feeding until the end of the growing season. Broadcast fertilizer in about a 25 to 50 square foot area around the plant based on the size and age of the plant. Older clematis will have more extensive root systems that reach further out from the base of the vine. Keep fertilizer at least 4 inches away from the base of the stem. Water deeply immediately after fertilizing your clematis.
To give your plant an extra boost of soil fertility, and to improve drainage, spread 1/2 inch of compost around the base of the plant every spring before the start of the growing season, and work it gently into the soil using your fingertips.
Discontinue fertilization if and when blooms appear. Applications of fertilizer during bloom can shorten the length of bloom time for the clematis. If blooms fade before midsummer, resume fertilization. Fertilize your clematis in fall with bonemeal to encourage root growth. Use approximately 1 ounce of bonemeal per square foot of area around the vine.
Watering Clematis
Water your clematis enough during the first growing season to keep soil moist but not soggy or wet. In following years, provide at least 1 to 2 inches of water per week in the absence of sufficient rainfall. It's best to deep soak less frequently than to splash a little water around the vine every day.
Spread a 2-inch layer of organic mulch around the base of the plant to conserve moisture and to prevent weeds from growing. Mulch must not be allowed to touch the base of the plant, so keep it at least 4 inches away from the base of the vine.
