High-alkaline soil is not as fertile as soil that is slightly acidic. Alkaline is the product of many inorganic metallic elements. Montana lies in hardiness zones 3 and 4, with a minimum average temperature range from negative 20 to negative 40 degrees Fahrenheit. Hardy perennials that do well in alkaline soil include wild columbine, candytuft and pincushion flower.
The wild columbine is a suitable perennial for Montana gardens, according to "The Montana Gardener's Companion: An Insider's Guide to Gardening Under the Big Sky," by Bob Gough and Cheryl Moore-Gough. The columbine ranges in height from 2 to 3 feet. The plant blooms in the spring and summer with red flowers that attract hummingbirds. The plant sprouts from a single rootstock that regenerates after fires.
Candytuft blooms in the spring. The plant reaches a height of 10 inches and spreads to a width of 2 feet. The leaves are green and alternate up the stem to the flowers, which are white and purple. Candytuft is a fire-resistant plant, according to the Montana State University Extension. In the wild, it grows in clumps, along slopes and in forests. In the garden, use it in edging, in a border garden or in a wildflower garden.
The pincushion flower is another native flower suited to the alkaline soil in Montana. The slender stems of the plant are greenish gray, branched and curved, according to "The Right Plant, Right Place: Over 1400 Plants for Every Situation in the Garden," by Nicola Ferguson. The plant grows to a height of 12 inches. The red flowers bloom throughout the summer. In the garden, the plant grows best in dry soils with full sun. The pincushion flower attracts bees and butterflies.