Dutch Crocus, Giant Crocus, Spring Crocus
Crocus x luteus 'Yellow Mammoth'

Family: Iridaceae (eye-rid-AY-see-ee) (Info)
Genus: Crocus (KROH-kus) (Info)
Species: x luteus
Cultivar: Yellow Mammoth
Additional cultivar information:(aka Golden Yellow, Dutch Yellow, Golden Mammoth, Large Yellow, Mammoth Yellow)
Synonym:Crocus x stellaris
Synonym:Crocus flavus
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Category:

Alpines and Rock Gardens

Bulbs

Height:

under 6 in. (15 cm)

Spacing:

3-6 in. (7-15 cm)

Hardiness:

USDA Zone 3a: to -39.9 C (-40 F)

USDA Zone 3b: to -37.2 C (-35 F)

USDA Zone 4a: to -34.4 C (-30 F)

USDA Zone 4b: to -31.6 C (-25 F)

USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

Sun Exposure:

Sun to Partial Shade

Light Shade

Danger:

All parts of plant are poisonous if ingested

Bloom Color:

Gold (Yellow-Orange)

Bloom Time:

Late Winter/Early Spring

Mid Winter

Foliage:

Herbaceous

Variegated

Other details:

Average Water Needs; Water regularly; do not overwater

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

Patent Information:

Non-patented

Propagation Methods:

By dividing rhizomes, tubers, corms or bulbs (including offsets)

Seed Collecting:

N/A: plant does not set seed, flowers are sterile, or plants will not come true from seed

Regional

This plant has been said to grow in the following regions:

Garberville, California

Clinton, Connecticut

Hawkinsville, Georgia

Logansport, Indiana

East Longmeadow, Massachusetts

Florence, Mississippi

Albuquerque, New Mexico

Akron, Ohio

Salt Lake City, Utah

Newport News, Virginia

Vancouver, Washington

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Gardeners' Notes:

3
positives
0
neutrals
0
negatives
RatingContent
Positive

On Mar 10, 2012, JonthanJ from Logansport, IN wrote:

Today's show in my scree reminds me that these guys bloom just a little bit ahead of the Crocus vernus. These guys popped in last week's warmer weather. Today, I found shoots from C. vernus budding. Yellow Mammoth give more flowers to a shoot as well, more like the snow crocus- also narrower leaves.

Positive

On Apr 15, 2008, ladychroe from Bridgewater, NJ wrote:

This is one of the few crocus that, in my opinion, really have presence in the garden. Very bright and large-flowered. Mine are planted near the house so I can see them from the windows, but they can be seen all the way from the street, too.

Positive

On Mar 14, 2008, David_Paul from Clinton, CT (Zone 6b) wrote:

Sold by Van Engelen as "Crocus flavus Yellow Mammoth".

The Pacific bulb society writes of c. flavus "This is a wild, or typical, form of the commonly grown early spring yellow crocus. Usually seen in gardens in the larger sterile form 'Golden Yellow' (syn. 'Dutch Yellow', 'Yellow Mammoth')."