Solidago altissima (Late Goldenrod) - photos and description

Species is rhizomatous, a colony of S. altissima.

Inflorescence is not leafy (S. lepida has a leafy inflorescence).

Inflorescence is not leafy (S. lepida has a leafy inflorescence).

Bottom of leaf blade. I would call this quite hairy, both on the leaf surface and on the nerves, especially when compared to S. lepida.

 Leaf nerves villous.

Top of leaf mid-stem, FNA describes this hairiness as +- scabrous.

Stems pubescent.

Leaf mid-stem, shallowly toothed; This species has large leaves among Goldenrods.

General: Tall perennial with single stems, a pyramidal inflorescence, and leaves 4x long as wide. Plants rhizomatous, stem is pubescent, leaves have various levels of pubescence.

Note: this species and Solidago lepida have been split by taxonomists from Solidago canadensis. Solidago canadensis as now described is not found in Saskatchewan, grows in eastern and central Canada.

Flowers: Inflorescence is a pyramid-shaped panicle. Inflorescence is not leafy (note that similar species S. lepida has a leafy inflorescence). We measured a single flower at 4 mm diameter and 5 mm long.

Leaves: Leaves are alternate and reduced in size upwards, sessile, lanceolate to elliptical, finely serrate. Top of leaf scabrous (short stiff hairs) and with various degrees of pubescence of the veins and surface of the bottom of leaves. We measured a leaf at 11 cm long by 2 cm wide.

Height: Height is listed in Flora of North America to 200 cm, we measured plants to 115 cm tall.

Habitat: Open woods, scrublands, and moist meadows. Dr. Semple of the University of Waterloo and author of the FNA treatment of S. altissima has published a North American range map for S. laltissima (can be viewed on the U Waterloo link below). It shows S. altissima occurs in SK from the northern Parklands south to the United States... south  of a diagonal line from just south of Duck Mountain on the MB border west across SK to about Lloydminster on the AB border.

Abundance: Common.

Origin: Native.

Similar species: Very similar to Solidago gigantea which is a taller goldenrod with a pyramidal inflorescence. However that species has glabrous stems, while the stems of Solidago altissima are pubescent.

Somewhat similar to Solidago mollis which is also a taller goldenrod with a pyramidal inflorescence. However that plant has leaves only 2-3x as long as wide, and is covered in fine hairs (puberulent) making its foliage velvety to touch and giving it a greyish-green appearance.

And, very similar to Solidago lepida which was split from Solidago canadensis along with Solidago altissima (the plant described on this page).

To distinguish between S. altissima and S. lepida (from the FNA key) it’s the hairiness of the leaves and leafiness of the inflorescence:

- S. altissima leaves moderately to densely villous or strigillose, sometimes more so on abaxial (leaf bottom surface) nerves... (leaves moderately or densely hairy).

- Solidago lepida leaves glabrous or sparsely villoso-strigillose, more so abaxially than adaxially (leaf top surface), especially along main nerves... (leaves hairless or sparsely hairy).

- The FNA species description of
S. lepida states its inflorescence usually leafy while the inflorescence of S. altissima is not described as leafy. We observed this with both species.

- S. lepida with leaves lower on stem to mid- stem having leaf surface hairless, we observed this, too. S. altissima having leaf top surface with hairs.

Also, S. lepida has varying degrees of minute glandular hairs in its inflorescence and upper leaves, however FNA states a 30x-70x magnification is needed to see them. We use a good 10x loupe and examined many flower heads  but couldn’t see any glandular hairs, I guess not enough magnification. So no help in identification.

Vascular Flora of Alberta states S. altissima "stems often with large (1-3 cm) insect galls, S. lepida stems rarely with galls". The day we photographed these plants we saw dozens of these Solidago plants, no galls on any stems, so no help.

S. canadensis is still described by taxonomists, but Dr. Semple of the U of Waterloo states S. canadensis as it's now described is not found in Saskatchewan, it is found in Eastern and Central Canada.

More information:

University of Waterloo Astereae Lab. (Dr. Semple of the Astereae Lab is one of the authors of the Solidago treatment in FNA).

Flora of North America (FNA).

When and where photographed: We took the above photos August 6th, boreal forest in Duck Mountain Provincial Park, about 300 km northeast of our home in Regina, SK.