Intermediate Tulip Growing: Divisions, Forcing & Extended Displays

Mastering Tulip Diversity

The 15 official tulip divisions represent centuries of breeding and selection. Understanding these categories enables sophisticated garden design and informed variety selection. This guide explores the full range of tulip types and advanced cultivation techniques.

The 15 Official Divisions

Division 1: Single Early

Characteristics:

• Bloom: Late March-early April
• Height: 10-14 inches
• Form: Single, cup-shaped

Best Uses:

• Early color
• Containers
• Forcing

Top Varieties:

Division 2: Double Early

Characteristics:

• Bloom: Late March-early April
• Height: 10-12 inches
• Form: Peony-like double

Notes:

• Heavy flowers may droop
• Excellent for cutting
• Fragrant varieties exist

Top Varieties:

Division 3: Triumph

The most versatile and widely grown class.

Characteristics:

• Bloom: Mid-April
• Height: 16-20 inches
• Form: Classic cup

Strengths:

• Huge color range
• Strong stems
• Weather resistant
• Great for cutting

Top Varieties:

Division 4: Darwin Hybrid

The best for perennializing.

Characteristics:

• Bloom: Mid-April
• Height: 20-24 inches
• Form: Large, substantial

Strengths:

• Excellent return rate
• Very large flowers
• Strong stems
• Bold colors

Top Varieties:

Division 5: Single Late

Characteristics:

• Bloom: Late April-May
• Height: 24-28 inches
• Form: Egg-shaped to cup

Strengths:

• Tall and elegant
• Long-lasting
• Many colors
• Excellent cut flowers

Top Varieties:

Division 6: Lily-Flowered

Characteristics:

• Bloom: Late April
• Height: 18-24 inches
• Form: Pointed, reflexing petals

Notes:

• Elegant, distinctive form
• Good for cutting
• Wind can damage

Top Varieties:

Division 7: Fringed (Crispa)

Characteristics:

• Bloom: Late April
• Height: 18-26 inches
• Form: Crystalline fringed edges

Notes:

• Unique, intricate appearance
• Various base flower forms
• Good cut flowers

Top Varieties:

Division 8: Viridiflora

Characteristics:

• Bloom: Late April-May
• Height: 12-20 inches
• Form: Green stripes on petals

Notes:

• Unusual coloring
• Long-lasting
• Conversation pieces

Top Varieties:

Division 9: Rembrandt

Characteristics:

• Bloom: Late April
• Form: Broken color patterns

Historical Note: Original Rembrandts had viral patterns (Tulip Breaking Virus). Today's varieties have stable genetic patterns, not virus-caused breaks.

Division 10: Parrot

Characteristics:

• Bloom: Late April-May
• Height: 16-22 inches
• Form: Ruffled, twisted petals

Notes:

• Dramatic, exotic appearance
• Heavy heads need support
• Originated as mutations

Top Varieties:

Division 11: Double Late (Peony-Flowered)

Characteristics:

• Bloom: Late April-May
• Height: 16-20 inches
• Form: Fully double, peony-like

Notes:

• Very heavy flowers
• Fragrant varieties
• Need support or shelter

Top Varieties:

Division 12: Kaufmanniana

"Waterlily Tulips"

Characteristics:

• Bloom: March-early April
• Height: 4-10 inches
• Form: Opens wide, flat

Strengths:

• Very early
• Reliably perennial
• Often mottled foliage
• Rock garden ideal

Top Varieties:

Division 13: Fosteriana (Emperor)

Characteristics:

• Bloom: Early-mid April
• Height: 8-18 inches
• Form: Large, long blooms

Strengths:

• Very large flowers
• Early bloom
• Good perennialization
• Bold colors

Top Varieties:

Division 14: Greigii

Characteristics:

• Bloom: Early-mid April
• Height: 8-14 inches
• Form: Various, often multi-flowered

Distinguishing Feature: Maroon-mottled or striped foliage

Strengths:

• Attractive foliage
• Fairly reliable return
• Rock gardens
• Containers

Top Varieties:

Division 15: Species (Miscellaneous)

Wild species and their selections.

Characteristics:

• Bloom: Various (often early)
• Height: 4-18 inches
• Form: Variable

Strengths:

• Most reliably perennial
• Often naturalizing
• Rock garden favorites
• Unique charm

Notable Species:

Forcing Tulips Indoors

Pre-Chilling Requirements

Cold Period:

• Duration: 12-16 weeks
• Temperature: 35-45°F (2-7°C)
• Darkness preferred
• Consistent temperature critical

Methods:

• Refrigerator (produce drawer, NO fruit)
• Cold garage or shed
• Outdoor cold frame
• Purchased pre-chilled bulbs

Forcing Process

Week 1-16 (Cold Period):

1. Pot bulbs in fall
2. Water thoroughly
3. Place in cold location
4. Keep barely moist
5. Check occasionally for root growth

Week 16-19 (Forcing):

1. Move to cool room (50-55°F)
2. Low light for 1-2 weeks
3. Gradually increase light
4. Move to bright, cool location
5. Blooms in 2-4 weeks

Best Varieties for Forcing

Perennialization Strategies

Choosing Perennial Types

Best Bets:

• Darwin Hybrids
• Species tulips (Division 15)
• Kaufmanniana, Fosteriana, Greigii

Cultural Practices for Return

1. Full sun location
2. Excellent drainage (critical)
3. Let foliage mature completely
4. Fertilize after bloom
5. Avoid summer irrigation
6. Hot, dry summer conditions ideal

Why Tulips Decline

• Bred for first-year performance
• Bulb splits into smaller offsets
• Insufficient photosynthesis
• Too much moisture in dormancy
• Inadequate chilling
• Shallow planting

Extended Season Design

Bloom Sequence Planting

Layered Planting (Lasagna)

Bottom Layer (8-10"): Large Darwin Hybrids, Single Late Middle Layer (6-8"): Triumph, Lily-flowered Top Layer (4-6"): Small bulbs (crocus, muscari)

Color Themes Through Season

Week 1-2: White/yellow species Week 3-4: Pink/salmon earlies Week 4-5: Red/purple triumphs Week 5-6: Dark/dramatic lates

Propagation

Natural Multiplication

Tulips produce offsets (daughter bulbs):

• Visible after lifting
• Separate and replant
• May take 2-3 years to bloom size
• Darwin Hybrids multiply best

From Seed (Species Only)

Process:

1. Collect ripe seed
2. Sow in fall
3. Cold stratification needed
4. Germination spring or second spring
5. 4-7 years to first bloom

Understanding the full range of tulip divisions enables sophisticated planting designs and informed variety selection. Combine early, mid, and late varieties for weeks of color, and choose perennial types for returning displays.