St. John's Wort

hypericum calycinum

Also known as: ["Rose of Sharon","Aaron's Beard"]

Family: Hypericaceae Genus: Hypericum Category: Shrubs

Overview

A low-growing, evergreen shrub with large, yellow flowers and small, oval leaves.

Benefits & Perks

["long-flowering","deer resistant","wildlife attractant (bees, butterflies, birds)","drought tolerant","shade tolerant"]

Botanical Classification

Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Malpighiales
Family: Hypericaceae
Genus: Hypericum
Botanical Name: Hypericum calycinum

Plant Characteristics

Basic Information
  • Category: Shrubs
  • Suitable Location: ground cover in garden beds, slopes, or as a low hedge
  • Suitable For:
    Beginners Busy People (low Maintenance) Outdoor Landscapers Wildlife Supporters
  • Is Weed: No
  • Allergenicity: low
Environmental Needs
  • Climate: {"temperatureRange":"–15–35°C"}
  • Hardiness: {"zones":"5–9"}
  • Misting: rarely required, only if ambient humidity is very low
  • Drainage: Moderate to fast-draining; avoid waterlogged conditions.
  • Soil Type: Well-draining, loamy soil with organic matter; tolerates average garden soil.
Maintenance Level
  • Maintenance Level: moderate
  • Toughness Level: high
  • Pruning Frequency: Annually after flowering or every 2–3 years to rejuvenate.
  • Pruning Intensity: Moderate; remove up to one-third of old growth to encourage new shoots.
Care Details

Ideal Sunlight Coverage:
Full sun to partial shade; 6–8 hours of direct sunlight in cooler climates, partial shade in hot regions.

Sunlight Tolerance Tips:
Acclimate plants gradually to intense sunlight; protect from harsh afternoon sun in hot climates; adjust placement based on seasonal light changes.

Warning Signs: Yellowing leaves, root rot, or stunted growth indicate poor soil conditions or improper drainage.

Care Requirements

Care Difficulty
easy

moderate

Sunlight

full sun to partial shade

Morning sun is ideal; provide shade during peak heat; rotate plants for even light exposure.

Watering

every 7–10 days during active growth, reduce in winter

Water thoroughly until runoff, allow soil to dry slightly between waterings, avoid waterlogging.

Soil

well-drained, loamy soil with moderate organic content

pH: Slightly acidic to neutral (pH 6.0–7.0).

Ensure good drainage; amend with organic matter; avoid compacted soil.

Temperature

Hardy in USDA zones 5–9; prefers 60–75°F (15–24°C); tolerates cold but may suffer in extreme heat.

Protect from frost; avoid sudden temperature fluctuations; maintain consistent soil moisture in heat.

Fertilizing

every 4–6 weeks during spring and summer

Fertilize lightly; apply before new growth emerges; stop fertilizing in late summer to avoid tender growth.

Propagation

Methods

Stem cuttings or layering; softwood cuttings in spring or early summer yield best results.

Step-by-Step Propagation Guide
  1. Take 4–6 inch cuttings.
  2. Remove lower leaves.
  3. Dip in rooting hormone.
  4. Plant in medium.
  5. Maintain humidity.

Best Time: Spring or early summer when the plant is actively growing.

Environment

High humidity (70–90%), warm temperatures (65–75°F), and indirect light.

Medium

Peat-based mix with perlite or sand for good drainage and aeration.

Hormone

Rooting hormone is recommended to improve success rates.

Timeline

Roots develop in 4–8 weeks; plants may take a full growing season to establish.

Tools Needed

Pruning shears, rooting hormone, small pots, misting spray bottle, plastic bags or propagation dome.

Quick Tips

Use healthy, non-flowering stems; maintain consistent moisture; provide bottom heat if possible.

Pruning & Repotting

Pruning Guide
Method

Selective thinning of branches; heading back to promote denser growth.

Pruning Plan

Prune to maintain shape, encourage bushiness, and remove dead or diseased growth; best done after flowering or in late winter/early spring.

Tools

Pruning shears, loppers (for larger branches), sterilizing solution.

Checklist

Sterilize tools; prune dead or crossing branches; make clean cuts just above buds; clean up debris.

Repotting Guide
Best Season

Early spring before new growth begins.

Pot Size

Increase pot size by 2–3 inches in diameter; ensure good drainage holes.

Method

Remove plant gently; trim roots if necessary; place in a slightly larger pot with fresh soil; water thoroughly.

Suggestions

Repot every 2–3 years or when roots fill the container; beneficial for container-grown plants to refresh soil and space.

Checklist

Choose appropriate pot size; prepare fresh soil mix; handle roots carefully; water after repotting; place in appropriate light.

Advanced Care Tips

Watering Mastery
Watering Checklist

Check soil moisture before watering; water deeply; ensure proper drainage; adjust for weather conditions.

How to Apply Water Properly

Water at the base of the plant, ensuring moisture reaches the root zone; water early in the morning to minimize evaporation and fungal issues.

Pro Tip: Use a soaker hose to deliver water directly to the roots, reducing waste and leaf wetness.
Watering Schedule Tips

Water deeply once a week during active growth, reducing frequency in winter; adjust based on rainfall and soil moisture.

Soil Improvement

Add compost or well-rotted manure for fertility; mix in perlite or sand for drainage; avoid heavy clay soils.

Temperature Stress Management
Signs of Temperature Issues

Chlorosis, leaf scorch, bud drop, or stunted growth in extreme heat; wilting or leaf drop in cold stress.

Cold Stress

Leaves may turn yellow or brown; growth slows; may die back in severe cold; root damage possible.

Solution: Mulch heavily in winter; protect from freezing winds; move potted plants indoors or to a sheltered location.

Hot Stress

Wilting, leaf scorch, reduced flowering, or leaf drop due to excessive heat and dryness.

Solution: Provide shade during peak heat; increase watering; use mulch to retain soil moisture; ensure good air circulation.

Fertilizing Guide
Fertilizing Checklist

Use balanced fertilizer; apply in early spring; water after fertilizing; avoid contact with stems or leaves.

Fertilizing Method

Use a balanced, slow-release fertilizer in early spring; avoid over-fertilizing, especially in late summer or fall.

Common Problems & Solutions

Yellowing leaves in Hypericum calycinum may indicate nutrient deficiencies, overwatering, or pest infestations such as spider mites or aphids, which disrupt chlorophyll production and photosynthesis.

Wilting in Hypericum calycinum can be caused by water stress, either due to drought or overwatering, leading to root damage and impaired water uptake, which may result in leaf drop and plant decline.

Leaf spots on Hypericum calycinum may be caused by fungal or bacterial pathogens, such as Cercospora or Xanthomonas, leading to defoliation, reduced photosynthesis, and weakened plant vigor.

Rotting in Hypericum calycinum is often associated with root or stem rot caused by fungal pathogens like Phytophthora or Fusarium, typically resulting from overwatering or poor drainage, leading to plant death if untreated.

Toxicity Warning

Cats
Slightly Toxic

Cats that ingest Hypericum calycinum berries may experience mild gastrointestinal upset and photosensitivity. The plant's compounds can irritate the digestive tract and increase sensitivity to sunlight in felines.

⚠️ Symptoms:
vomiting diarrhea lethargy photosensitivity
🌿 Toxic Parts:
berries
⚡ Toxic If:

if eaten

Prevent cats from accessing the berries. If ingestion is suspected, seek veterinary advice promptly.
Dogs
Slightly Toxic

In dogs, ingestion of Hypericum calycinum berries may lead to mild gastrointestinal distress and potential photosensitivity. The toxic compounds can cause irritation to the digestive system and increase sensitivity to sunlight.

⚠️ Symptoms:
vomiting diarrhea lethargy photosensitivity
🌿 Toxic Parts:
berries
⚡ Toxic If:

if eaten

Keep dogs away from the berries. If ingestion occurs, monitor for symptoms and consult a veterinarian if necessary.
Humans
Slightly Toxic

Hypericum calycinum contains hypericin and other compounds that can cause mild gastrointestinal upset and photosensitivity when ingested in significant quantities. The physiological impact is generally limited to mild irritation of the digestive tract and increased sensitivity to sunlight.

⚠️ Symptoms:
nausea vomiting diarrhea photosensitivity
🌿 Toxic Parts:
berries
⚡ Toxic If:

if eaten

Avoid ingestion. Wear protective clothing when handling the plant, especially during prolonged sun exposure.
Important: Keep this plant out of reach of children and pets. If ingestion occurs, contact poison control or veterinary services immediately.

Frequently Asked Questions

Q: Is Hypericum calycinum toxic to pets?

A: Yes, it is mildly toxic to dogs and cats if ingested.

Q: Does Hypericum calycinum attract wildlife?

A: Yes, it attracts bees, butterflies, and birds due to its nectar-rich flowers.

Q: Can Hypericum calycinum grow in shade?

A: Yes, it is shade tolerant and can thrive in partial to full shade.

Quick Reference
Family: Hypericaceae
Care: easy
Light: full sun to partial shade
Water: every 7–10 days during activ
Suitable For: ["beginners","busy people (low maintenance)","outdoor landscapers","wildlife supporters (attracts bees, butterflies, birds)"]
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