Is Potash Good for Clematis?

Clematis

• Clematis plants are in the buttercup family. There are some 250 species of clematis and hundreds of hybrids. The word clematis comes from the Greek word for vine, though upright growing forms exist. Clematis plants are vigorous, heavy-feeding evergreens or, more commonly, deciduous plants. Clematis are native to fertile, temperate regions of the Northern Hemisphere. Chinese and Japanese species created interest among horticulturists in Europe in the 1850s, and new varieties were eagerly developed and introduced. Modern hardy, disease-resistant varieties make garden clematis culture within reach of the average home gardener.

Clematis Culture

• Clematis require well-drained soil, rich in organic matter, with a pH level of 7.0. Clematis thrive with at least five hours of sunlight daily. Pastel varieties tend to fade in direct sun; provide bright or dappled shade for these during the most intense hours of exposure. Dig a hole 2 feet wide and deep and back-fill with half garden topsoil and half amended soil. Plant clematis with the base of the plant 3 to 5 inches below the soil level to keep the roots cool. Spread a 3- to 4-inch layer of organic mulch atop the root zone 8 inches out from the stem. Begin feeding clematis early in spring when new buds are 2 inches long.

Fertilizer

• The three prominent numbers on U.S. national standard commercial fertilizer labels indicate the amounts of primary nutrients in percentages contained in the formula. The first number represents the amount of available nitrogen, the second number represents the available phosphate, and the third number, the available potash. A label with 10-10-10 displayed contains 10 percent of each nutrient. The American Clematis Society recommends a feeding program alternating a high-potash fertilizer formulated to promote bloom (3-12-12), with an all-purpose blend (5-3-1) throughout the growing and blooming season.

Potash

• Potash production in the U.S. is a multimillion-dollar industry. Michigan, Utah and New Mexico are primary producers. Three mines in southeastern New Mexico provided 75 percent of the total U.S. production in 2010, according to a January 2011 report by the U.S. Geological Survey. U.S. and world production and consumption reached low points in 2009 as a result of high prices, weak demand and the economic downturn. Potassium is an essential nutrient for plants and humans, and potash is the most efficient source of fertilizer potassium. Other mineral and organic fertilizers have low potassium contents and are economically inefficient to transport beyond short distances.