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How to Grow Arum

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Arum

Arum maculatum

flower

Arum is a tuberous perennial plant native to Europe, known for its distinctive arrow-shaped leaves and unusual spathe flowers that range from pale yellow to deep purple. The plant produces striking mottled foliage and unique club-like inflorescences followed by bright red berries. It's a dramatic addition to woodland gardens and shaded borders.

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Example Arum timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Arum

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. First Arum blooms

    Around Apr 18

    ≈ 1 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Arum dates for your own zip code.

Growing Conditions

☀️
Sun: Partial shade to dappled shade; prefers 2-4 hours of indirect light
💧
Water: Keep soil consistently moist during growing season (spring-summer); reduce watering in dormancy (fall-winter). Avoid waterlogging.
📏
Spacing: 12-18 inches
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Days to maturity: Not applicable (flowering perennial); tubers establish in 1-2 growing seasons
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Planting depth: 4-6 inches for tubers

Soil

Type: Humus-rich, moist but well-draining soil
pH: 6.0-7.0
Amendments:
Compost Leaf mold Peat moss or coco coir Organic matter

Growing Zones

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Thrives in zones 5-9, prefers cooler temperate regions

5a 5b 6a 6b 7a 7b 8a 8b 9a

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Growth Stages

1

Dormancy

Fall to early spring (4-6 months)

Tubers underground, no visible growth; plant is resting

Keep soil dry but not completely desiccated; protect from frost if in cold regions; cool period helps break dormancy

2

Emergence & Vegetative Growth

Early spring (3-4 weeks)

Mottled arrow-shaped leaves emerge and unfurl; foliage expands with distinctive patterns

Begin regular watering; ensure consistent moisture; apply balanced fertilizer; remove dead foliage

3

Flowering

Mid to late spring (2-4 weeks)

Distinctive spathe (modified leaf) emerges, ranging from pale yellow to dark purple; spadix (flower spike) visible inside; produces strong odor

Do not disturb flowers; ensure adequate moisture; maintain shade conditions; note that smell attracts flies for pollination

4

Fruiting & Seed Development

Late spring to early summer (4-6 weeks)

Flowers fade; bright red berries develop in clusters on the spadix, ripening as foliage begins to decline

Reduce watering gradually; allow berries to ripen fully; monitor for self-seeding if desired; stop fertilizing

5

Senescence & Dormancy Preparation

Summer to fall (6-8 weeks)

Foliage yellows and dies back; tuber consolidates energy underground; plant prepares for rest period

Allow foliage to die back naturally; cease watering; stop fertilizing; mulch tubers lightly for frost protection

Companion Planting

Plan your garden →

Plant with:

Hellebores Hepatica Ferns Hostas Astilbe Primrose Wood anemone

Avoid planting near:

Direct sun-loving plants Drought-tolerant plants Aggressive spreading perennials

Common Pests

  • Increase humidity; spray with water; use insecticidal soap if severe

  • and

    Hand-pick; create barriers with copper tape; use organic slug bait; encourage ground beetles

  • Remove affected leaves; improve air circulation; avoid overhead watering; apply fungicide if necessary

  • Spray with water jet; use neem oil; encourage beneficial insects

Uses

🌿

Dramatic Woodland Garden Accent

Ornamental

The striking mottled foliage and unusual purple or yellow spathes make Arum a focal point in shaded borders and woodland gardens. The bright red berries that follow provide late-spring interest and attract birds. [source]

🦋

Pollinator & Bird Attraction

Wildlife

The distinctive flowers with their unique odor attract flies and other pollinators for reproduction. The ripening red berries are attractive to birds in early summer. [source]

🏠

Floral Arrangements & Cut Flowers

Household

The dramatic spathes are used by florists in unique cut arrangements. Berries can be dried for long-lasting botanical displays. [source]

Harvest Tips

Arum is grown ornamentally, not harvested. Allow berries to fully ripen (bright red) in early summer if collecting seeds. Foliage dies back naturally by early-mid summer; do not cut prematurely. Note: All parts are toxic if ingested; wear gloves when handling.

Fun Facts

  • 🌱 Arum maculatum has an unusual pollination strategy—its flowers produce a strong foul smell that attracts flies, which then become trapped briefly inside the spathe and transfer pollen before escaping.
  • 🌱 The plant's common names include 'Cuckoo Pint,' 'Lords-and-Ladies,' and 'Jack-in-the-Pulpit' (though true Jack-in-the-Pulpit is a different genus, Arisaema).
  • 🌱 All parts of the plant contain calcium oxalate crystals and are highly toxic if ingested; consuming even small amounts causes intense burning in the mouth and throat.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Mulch Partial Shade Perennial Pollination
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