Blackjack Oak

quercus marilandica

Also known as: ["Blackjack","Black Oak"]

Family: Fagaceae Genus: Quercus Category: Trees

Overview

A deciduous oak tree native to the eastern and central United States, known for its distinctive thick, dark bark and acorns.

Benefits & Perks

["wildlife attractant (bees, butterflies, birds)","drought tolerant","shade tolerant"]

Botanical Classification

Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Fagales
Family: Fagaceae
Genus: Quercus
Botanical Name: Quercus marilandica

Plant Characteristics

Basic Information
  • Category: Trees
  • Suitable Location: outdoor landscape in open areas with good air circulation
  • Suitable For:
    Outdoor Landscapers Wildlife Supporters
  • Is Weed: No
  • Allergenicity: low
Environmental Needs
  • Climate: {"temperatureRange":"–28–38°C"}
  • Hardiness: {"zones":"4–8"}
  • Misting: rarely required
  • Drainage: Fast-draining to prevent root rot.
  • Soil Type: Well-draining loamy or sandy soil with organic matter.
Maintenance Level
  • Maintenance Level: moderate
  • Toughness Level: high
  • Pruning Frequency: Annually in late winter or early spring; light pruning as needed year-round.
  • Pruning Intensity: Moderate; remove up to 25% of growth if necessary for health or shape.
Care Details

Ideal Sunlight Coverage:
Full sun (6–8 hours of direct sunlight daily); tolerates partial shade but may become leggy.

Sunlight Tolerance Tips:
Acclimate gradually if moving from shade to sun; protect from intense midday sun in summer; ensure good air circulation to prevent scorching.

Warning Signs: Yellowing leaves (overwatering or poor drainage); stunted growth (nutrient deficiency or compacted soil).

Care Requirements

Care Difficulty
moderate

moderate

Sunlight

full sun

Avoid sudden light changes; use shade cloth in extreme heat; rotate plant for even growth.

Watering

every 2–3 weeks during dry periods, less frequently in winter

Water thoroughly until runoff, ensure good drainage, and avoid frequent shallow watering.

Soil

well-drained, acidic to slightly alkaline loam

pH: Slightly acidic to neutral (pH 5.5–7.0).

Avoid heavy clay; ensure good aeration; test pH periodically.

Temperature

Hardy in USDA zones 5–9; tolerates temperatures from -20°F to 100°F; prefers moderate temperatures in spring and fall.

Protect from frost; water early to avoid heat stress; adjust care by season.

Fertilizing

annually in early spring with a balanced slow-release fertilizer

Test soil before fertilizing; avoid fertilizing in late fall; water well after application.

Propagation

Methods

Seed or root cuttings; seeds require stratification for germination.

Step-by-Step Propagation Guide
  1. Collect mature seeds or healthy root sections.
  2. Prepare medium.
  3. Plant seeds or cuttings.
  4. Maintain humidity.
  5. Transplant when rooted.

Best Time: Late winter or early spring for seeds; summer for root cuttings.

Environment

Warm (70–75°F), high humidity (70–80%), partial shade for cuttings.

Medium

Seed: moist sand or peat; cuttings: well-draining soil mix with perlite.

Hormone

Not necessary for seeds; rooting hormone can aid cuttings.

Timeline

Seeds: 18 months to germinate; cuttings: 4–8 weeks to root.

Tools Needed

Pruners, rooting hormone, pots, misting spray bottle, heating mat.

Quick Tips

Stratify seeds for 60–90 days; use bottom heat for cuttings; keep cuttings out of direct sun.

Pruning & Repotting

Pruning Guide
Method

Thinning cuts to open canopy; heading cuts to control size; avoid excessive topping.

Pruning Plan

Remove dead or diseased branches; shape for structure; encourage airflow; maintain natural form.

Tools

Hand pruners, loppers, pruning saw, sterilizing solution.

Checklist

Sterilize tools; prune during dormancy; make clean cuts; remove crossing branches.

Repotting Guide
Best Season

Early spring before new growth begins.

Pot Size

Increase pot size by 2–3 inches in diameter for container plants.

Method

Remove soil gently; prune roots if pot-bound; use fresh well-draining soil; ensure proper drainage.

Suggestions

Not typically repotted; container-grown plants may need repotting every 3–5 years.

Checklist

Check root bound status; prepare new pot; prune roots if needed; use fresh soil mix.

Advanced Care Tips

Watering Mastery
Watering Checklist

Check soil moisture before watering; water deeply; ensure drainage; adjust frequency by season.

How to Apply Water Properly

Water directly at the root zone, apply until water drains from the bottom, ensure soil is moistened to a depth of 6–8 inches, and water early in the morning or late in the evening to minimize evaporation.

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

Water deeply once every 7–10 days during spring and summer; reduce frequency to every 2–3 weeks in fall and winter, allowing soil to dry partially between waterings.

Soil Improvement

Add compost or aged manure for fertility; mix sand or perlite for drainage; use mulch to retain moisture.

Temperature Stress Management
Signs of Temperature Issues

Leaf scorch (brown edges) in excessive heat; leaf drop or dieback in prolonged cold; stunted growth in temperature stress.

Cold Stress

Leaves may curl or drop; growth slows or halts; roots can be damaged in poorly drained soil during freeze.

Solution: Mulch heavily around the base; protect roots with burlap wrapping in extreme cold; avoid overwatering in winter.

Hot Stress

Wilting despite moist soil; leaf scorch; reduced photosynthesis; premature leaf drop.

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

Fertilizing Guide
Fertilizing Checklist

Check soil pH; apply fertilizer in spring; water thoroughly after fertilizing.

Fertilizing Method

Use a balanced slow-release fertilizer in early spring; avoid high-nitrogen formulas; fertilize only once a year for established trees.

Common Problems & Solutions

Yellowing of leaves in Quercus marilandica can indicate nutrient deficiencies, such as iron chlorosis, or stress from environmental factors like drought or excessive waterlogging.

Wilting in Quercus marilandica is typically a sign of water stress, either due to insufficient soil moisture or root damage that impairs water uptake.

Leaf spots on Quercus marilandica are commonly caused by fungal pathogens like Tubakia or Guignardia, resulting in necrotic lesions that can affect photosynthesis and overall plant health.

Rotting, particularly root or crown rot, in Quercus marilandica is often caused by fungal pathogens such as Armillaria or Phytophthora, leading to decay of plant tissues and eventual decline.

Toxicity Warning

Cats
Slightly Toxic

Cats may experience gastrointestinal irritation if they ingest the acorns or leaves of Quercus marilandica due to the presence of tannins. Symptoms are typically mild but can be more severe in sensitive individuals.

⚠️ Symptoms:
vomiting diarrhea lethargy decreased appetite
🌿 Toxic Parts:
acorns leaves
⚡ Toxic If:

if eaten

Prevent cats from accessing acorns and leaves, and seek veterinary advice if ingestion occurs.
Dogs
Slightly Toxic

The acorns and leaves of Quercus marilandica contain tannins that can cause mild to moderate gastrointestinal upset in dogs if ingested. Prolonged or large ingestion may lead to more severe symptoms.

⚠️ Symptoms:
vomiting diarrhea loss of appetite abdominal pain
🌿 Toxic Parts:
acorns leaves
⚡ Toxic If:

if eaten

Keep dogs away from acorns and leaves, and consult a veterinarian if ingestion is suspected.
Humans
Slightly Toxic

Quercus marilandica, commonly known as blackjack oak, contains tannins which can cause gastrointestinal distress if ingested in significant quantities. The acorns are particularly high in tannins, leading to potential toxicity.

⚠️ Symptoms:
nausea vomiting diarrhea stomach pain
🌿 Toxic Parts:
acorns leaves
⚡ Toxic If:

if eaten

Avoid consuming any parts of the plant, especially acorns, and ensure they are kept out of reach of children.
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 the Blackjack Oak suitable for urban environments?

A: Yes, it is drought-tolerant and can thrive in challenging urban conditions.

Q: Does the Blackjack Oak produce acorns?

A: Yes, it produces acorns that are a food source for wildlife.

Q: How fast does the Blackjack Oak grow?

A: It has a moderate growth rate, typically reaching maturity over several decades.

Quick Reference
Family: Fagaceae
Care: moderate
Light: full sun
Water: every 2–3 weeks during dry p
Suitable For: ["outdoor landscapers","wildlife supporters (attracts bees, butterflies, birds)"]
Get Expert Care Tips

Download the Plantious app for personalized care reminders and plant identification!

Google Play App Store
Share This Plant

Related Plants

Mongolian Oak
View
Turkey Oak
View
Nopalera Oak
View
Mediterranean Oak
View