Great St. Johnswort (Hypericum pyramidatum)

Great St. Johnswort

Hypericum pyramidatum

Great St. Johnswort is a tall, striking perennial that can reach heights of 2 to 5 feet. It is found in wet meadows, thickets, and along shorelines in Minnesota. This plant prefers moist, loamy soils and does well in full to partial sun. It produces showy yellow flowers in mid to late summer that attract pollinators. Its upright form and bright blooms make it a valuable addition to rain gardens, wetland restorations, and naturalized landscapes.

Characteristics

Type	Forb
Sun	Full Sun, Partial Sun, Shade
Soil	Clay, Loam, Sand/Gravel, Calcareous
Moisture	Mesic, Wet
Average Max Height (inches)	42
Suggested Plant Spacing (inches)	30
Bloom month(s)	July, August
Bloom Color or Type	Yellow
Dominance	Medium

Range Maps

Sowing Information

Sow seed onto a firm, weed-free seedbed. Hand-broadcast seed making two perpendicular passes for even coverage. If planting a mix, broadcast the grass component first and lightly rake/drag it into the top 1/8–1/4" of soil. Next, broadcast wildflower/forb seed and press it into the soil surface (with a roller/cultipacker or the back of a rake) to ensure good seed-to-soil contact. After seeding, apply a very light layer of clean, seed-free straw (or other weed-free, site-appropriate mulch) to reduce erosion and retain moisture without smothering seedlings. A good rainfall or thorough watering will help settle seed and mulch and improve germination.

Planting Information

Dig a hole in your planting site slightly larger than the plant’s root system. When placing the plant into the hole, ensure that the soil line remains consistent with its original level in the pot. Fill in around the roots with the excavated soil, gently firming it to eliminate air pockets. Water the plant thoroughly the same day to promote successful establishment.