Sun-loving mountain hollyhock is garden stunner

This sun-loving native perennial is a stunner in the wild and in the right garden location. For much of the summer Mountain Hollyhock (Iliamna rivularis) produces showy loose spikes of lavender-pink to almost white flowers. It grows in meadows, along stream banks, on forested slopes and in disturbed areas mainly east of the Cascades to Montana, south to Wyoming and north into British Columbia and Alberta. There are isolated pockets in Indiana, Illinois and West Virginia.

In spring, sturdy stems of Mountain Hollyhock grow from rootstock (a caudex) to form a nicely-shaped shrub from three to six feet high and several feet in diameter. The leaves range in size from a few inches up to five or six inches. They are palmate, resembling maple leaves, with three to seven triangular lobes, each with a large vein running to the tip. They are arranged alternately along the stem.

Like its distant cousin, the familiar garden hollyhock, the leaves and stems are covered in hairs. The leaves are soft, giving rise to common names like Checkermallow and Globemallow. Mallow means soft and is the common name for Mountain Hollyhock's botanical family, Malvaceae.

Flowers, one to one-and-a-half inches in diameter, appear in early summer, growing from the upper leaf axils on tall sturdy stalks. Lavender-pink to white in color, five overlapping, rounded petals form the corolla. In the center, multiple stamens (male flower parts) are joined at the base and spread out to surround the stigma (female flower part). Bloom can be prolonged by clipping off developing seed heads. This encourages new bloom stalks to grow from lower leaf axils.

Mountain Hollyhock seeds are borne in capsules that are round and flattened in wedge-shaped segments resembling a cheese wheel. The tough seed coats require some environmental scarification, such as wildfire or being roughened by tumbling in a stream, in order to germinate. In the ground, seeds can remain viable for up to a century. In the wild, they germination is triggered by wildfire, and Mountain Hollyhock returns early to burned over areas.

Native Americans chewed Mountain Hollyhock stems like gum, but there are no other known food or medicinal uses. Seeds can be toxic to children.

A relatively disease-free plant, Mountain Hollyhock is a favorite with deer and elk. Young leaves stripped from your garden specimen will quickly recover and the plants will still flower. Deer repellent sprays also help. Native bees, butterflies and hummingbirds are attracted to Mountain Hollyhock and aid in pollination.

In the garden, Mountain Hollyhock is happiest in moist, well-drained soils in full sun. It tolerates some shade and is drought-tolerant, but is more robust and blooms best and longest with adequate water and light. It makes a nice backdrop for shorter plants and can be used in borders or informal plantings. It is a true perennial and will regrow from rootstock, blooming every year.

Mountain Hollyhock grows in the moist forest and near the dry rockwall in the North Idaho Native Plant Arboretum, 611 S. Ella Ave. in Sandpoint. Pictures and a description can be found in “Landscaping with Native Plants in the Idaho Panhandle,” a KNPS publication available at local bookstores and the Bonner County History Museum adjacent to the Arboretum.

Native Plant Notes are created by the Kinnikinnick Native Plant Society. To learn more about KNPS and the North Idaho Native Plant Arboretum, visit www.nativeplantsociety.org.