Mother Nature's Montrose Garden: November 2022

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum): in winter

Attracting butterflies, other pollinators and birds is an important goal for many gardeners. The challenge is to provide plenty of food throughout the warm months – as well as some for winter. The fall-blooming sunflowers are a great way to extend the gardening season – even into late fall. And one of our favorites is the Stiff Goldenrod. The scientific name is currently under some debate: this plant is known as either Solidago rigida or Oligoneuron rigidum. The genus Oligoneuron includes other flat-topped Goldenrods. The name pronunciations are: so-lih-DAH-go RIH-jid-uh and ah-lih-go-NYEW-ron RIH-jid-um.

Stiff Goldenrod is native to much of the United States and southern Canada, with the exception of the Pacific Coast. In Colorado, Solidago rigida ssp. humilis grows wild on the Front Range and Eastern Plains. [1] The more common – and taller - Solidago rigida ssp. rigida occurs mostly on the midwestern plains and Eastern U.S.

Solidago rigida is a goldenrod of prairies, meadows and grassy woodland openings. The soils may be dry or not and range in texture from sandy to loamy. This hints that Stiff Goldenrod is adaptable to a range of garden conditions. And, contrary to popular belief, Goldenrods do not cause hay fever (that honor goes to Ragweed, which often blooms at the same time).

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum):
growth habit

Stiff Goldenrod is a winter-deciduous perennial. The plant dies back to a basal rosette, which may remain partly green throughout the cold season (above). The growth habit consists of this basal rosette, whose leaves may be up to 8 inches long and 2 inches wide, and erect flowering stems.

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum): foliage

The stout, upright stems begin their growth in spring. Stems are usually 3-5 ft. tall. The stems have alternate, clasping leaves that decrease in size up the stem. The leaves are lance-shaped to elliptical, gray-green and stiff at maturity. The entire plant is covered in stiff hairs, giving leaves and stems a rough texture. Leaves often take on a showy red- or purple hue with the onset of cold weather.

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum):
flowering stalks

Stiff Goldenrod blooms anytime from August through October, depending on the weather. It often flowers for about a month in September or early October in Western Colorado gardens. But the plants remain showy well into winter.

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum):
note individual flower heads

The flowers are individually small, in typical sunflower ‘heads’ (heads have both petal-like ray flowers and central disc flowers). The flowering heads are bright yellow and clustered in flat terminal clusters at the ends of the stems (above). The blooming plants are quite showy, with the yellow clusters rising above other garden foliage (see below). The seeds, with their tufts of light colored hairs, remain on the plant into early winter. The seeds are enjoyed by seed-eating birds.

Goldenrods are easy to grow. This one is happy in whatever soil texture you have, and from pH of 5.0 to over 8. It can be grown in USDA Zones 3-9. Like most plants in the Sunflower family, Stiff Goldenrod does best in full sun, although it can be grown in part-shade. And it thrives in medium to dry soils, so is adaptable to a range of precipitation and irrigation regimens.

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum): seeds on plant

This is a ‘well-behaved’ goldenrod, in that it doesn’t spread by rhizomes. That being said, it does re-seed, sometimes prolifically, on bare soils. If that’s an issue, removed the seeds before they ripen. Otherwise, let the birds eat their fill and remove the seedlings in the spring. We choose the latter, cutting down the old stalks to 8-24 inches in the spring.

That’s really about all there is to growing Solidago rigida. Plants benefit from being divided every 2-3 years. And flowering stalks may need support in windy gardens. Plants grown in containers should be fertilized in the spring (recommended dose is fine). Plants in garden soil likely won’t need any fertilizer. And that’s about it.

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum): seeds are small

Stiff Goldenrod can be started from seed, but it does benefit from winter cold exposure. Even with that, germination percentage may be low. It’s best to use fresh seed, and we’ve found it easiest to plant seeds in pots that are over-wintered outdoors. Plant seeds in late fall to early winter. Barely cover the seeds and be sure to water pots during dry spells. Seedlings will sprout as weather warms in spring.

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum):
emerging seedlings

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum): seedlings

All Goldenrods are great habitat plants, and Stiff Goldenrod is no exception. The flowers attract a wide range of late-season pollinators, including Honey Bees, native bees, pollinator flies, moths and butterflies. It’s often planted as a source of nectar for Monarch butterflies. And the pollen is an important source of food for the young of native bees. For some great pictures of insect visitors see: Restoring The Landscape With Native Plants: Native Plant of the Week: Stiff Goldenrod ~ Oligoneuron rigidum (Solidago rigida).

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum):
many pollinators (including Honey bees) love this plant

The seeds are loved by seed eating birds. The goldfinches and others go to great lengths to eat the seeds in Mother Nature’s Montrose Garden (below). The winter stalks also make great perches for birds.

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum):
finches love the seeds

Why consider Solidago rigida for your home garden? For many gardeners, the habitat value is enough of an incentive. Plant them near or in an herb or vegetable garden to take advantage of the beneficial insects attracted by this plant. Or use as a transition plant between the garden and more natural areas. You could even plant it in a large container if space is limited.

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum):
in Mother Nature's Montrose Garden

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum):
Lovely contrast with Common Ironplant

We also love the looks of Stiff Goldenrod. It provides a nice shot of pure yellow in late season. It looks particularly nice when contrasted with the purples and blues of late-blooming asters, Azure Blue Sage (Salvia azurea), Common Ironplant (Vernonia fasciculata), Joe Pye Plant (Eutrochium maculatum) and Hoary Vervain (Verbena stricta). We also appreciate the red-purple foliage colors in fall.

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum):
good fall color

Stiff Goldenrod is used as a traditional herbal medicine by several native cultures. [3, 4] Young leaves can be cooked and eaten as greens (as you would cooked spinach). [5] And yellow, orange and brown dyes can be obtained from all parts of the plant. [6, 7]

Stiff Goldenrod (Solidago rigida / Oligoneuron rigidum):
valued habitat plant

In summary, Stiff Goldenrod is an easy-to-grow plant that provides pollinator habitat through fall and into winter. Plants are showy, providing a spot of yellow in the fall garden. We heartily recommend this useful perennial for the home gardener.