Shrub
Kalm St. Johnswort
Hypericum kalmianum
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 Height
2-3 Feet
Size
Small
Mature Width
2-3 Feet
Mature Form
Rounded
Native To:
United States (and Illinois)
USDA Hardiness Zone
4 - 7
Soil Conditions
Moist, Well-Drained
Wet
Tolerance
Alkaline Soil
Dry Sites
Salt
Soil Compaction
Wet Sites
Wind
Exposure/Light Requirements
Full Sun
Uses
Border
Foundation
Massing
Specimen
Foliage Color
Green
Fall Foliage Color
Green
Yellow
Pests and Problems
Environmental Damage
Fungal Disease
Additional Notes
Related Resources
Home, Yard & Garden Pest Guide
The Home, Yard & Garden Pest Guide (C1391) provides is written for homeowners and other residents and provides nonchemical and current chemical recommendations for controlling pests associated with trees, shrubs, turf, flowers, groundcovers, vegetables, fruit, and houses. In addition, you'll find detailed information about integrated pest management, pesticide safety, and pesticide application and calibration techniques. This publication may be purchased at your local University of Illinois Extension Unit office, or by calling 800-345-6087, or by placing an order online (search for "C1391").
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Illinois Commercial Landscape and Turfgrass Pest Management Handbook
The Illinois Commercial Landscape and Turfgrass Pest Management Handbook (ICLT) is written for professional applicators and provides nonchemical and current chemical recommendations as well as application timing information for all major pests of turf, woody ornamentals and herbaceous ornamentals. This publication may be purchased at your local University of Illinois Extension Unit office, or by calling 800-345-6087, or by placing an order online (search for "ICLT").
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U of IL - Distance Diagnosis through Digital Imaging
A free plant, weed, insect and disease identification service available through your local University of Illinois Extension office. Center Educators or State Specialists review & respond to information and digital images submitted by local Extension office personnel. Some samples may require further examination or culture work (nominal fee involved) at the U of IL Plant Clinic.
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U of IL - Plant Clinic
Services include plant and insect identification, diagnosis of disease, insect, weed and chemical injury (chemical injury on field crops only), nematode assays, and help with nutrient related problems, as well as recommendations involving these diagnoses. Microscopic examinations, laboratory culturing, virus assays, and nematode assays are some of the techniques used in the clinic.
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