University of Illinois Extension
University of Illinois Extension - Selecting Shrubs for Your Home
http://www.urbanext.uiuc.edu/shrubselector
Kalm St. Johnswort
Hypericum kalmianum
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Kalm St. Johnswort flowers
Size:
Size: small
Small

Medium

Large
Exposure/ Light Requirements:
Full Shade not required.
Full Shade
Full Sun required.
Full Sun
Partial Sun/Shade not required.
Partial Sun/Shade
Hardiness Zone: 4 - 7 
Mature Height: 2-3 Feet
Mature Width: 2-3 Feet
Features: Bright yellow flowers (July- August); blue green leaves in summer; autumn color is yellow green.
Culture: Full sun; prefers moist to wet sites, but can tolerate some dryness; tolerates alkaline soil.
Cultivars:
  • 'Ames' - Neat, mounded form, 2-3 feet tall.
  • 'Gemo' - Flowers from July through September.
Mature Form: Rounded
Native To: United States (and Illinois)
Soil Conditions:
Dry
Soil condition: Moist, Well-DrainedMoist, Well-Drained
Soil condition: WetWet
Tolerance:
Tolerance: Alkaline SoilAlkaline Soil
Tolerance: Dry SitesDry Sites
Tolerance: SaltSalt
Tolerance: Soil CompactionSoil Compaction
Tolerance: Wet SitesWet Sites
Tolerance: WindWind
Uses:
Barrier
Use for: Border.Border
Use for: Foundation.Foundation
Hedge
Use for: Massing.Massing
Naturalizing
Screen
Use for: Specimen.Specimen
Foliage Color: Green
 
Fall Foliage Color: Green
Yellow
 
Additional Notes: