Trifolium incarnatum L.

Symbol: 
TRIN3
Group: 
Dicot
Family: 
Fabaceae
Uses: 
Beautification
Grazing
Pasture
Pollinators
Soil Improvement (Green manure)
Soil Protection (Cover Crop)
Description: 

Herbaceous winter annual legume with an erect growth habit. Plants are densely hairy. Unbranched stems reach 1-3 feet tall. Inflorescence is a cylindrical or conic flower head 1-2 1/2 inches long containing many small (1/2 inch) bright scarlet (or occasionally white) florets that open in succession from the bottom to the top of the head. Trifoliate leaves are palmately trifoliolate, with egg- to heart-shaped leaflets 1/2 to 1 inch long, finely toothed near the tip.  Stipules are elliptic, blunt, violet-veined, reddish-tipped, and mostly fused with the stem. Taproot and numerous fibrous roots extend 12-20 inches deep. Seeds are yellow and borne singly in small pods. Seeds are larger and more rounded than red clover seeds, with approximately 120,000 to 150,000 seeds per pound.

Identification

Type: 
Legume
Life cycle: 
Winter annual
Growth Season: 
Cool
Identification Characteristics: 

Crimson clover plants are densely hairy. Unbranched stems originate from a rosette, reaching 1 to 3 feet tall. It has a central taproot and many fibrous roots. The trifoliate leaves have egg- to heart-shaped leaflets that are ½ to 1 inch long and are distinguished from the leaves of red clover by their rounded tips and absence of V-shaped leaf marks.

Inflorescence: The cylindrical or conic flower heads at the ends of stems are 1 to 2 ½ inches long (2.54cm) and contain many small (½ inch; 1.27 cm) bright scarlet (or occasionally white) florets that open in succession from the bottom to the top of the flower head. Flowering is induced by day-lengths over 12 hours, and in the northern hemisphere, plants bloom between April and August, depending on the climate and region. Flowers are generally self-fertile but not self-pollinating (about 68 to 75% out-crossing), relying on bees that visit the flowers for nectar and pollen. Crimson Clover Inflorescence

Seeds: Crimson clover seeds are yellow and borne singly in small pods and are larger and more rounded than red clover seeds, with approximately 120,000 to 150,000 seeds per pound (54,531 to 68,039 seeds / kg). Typical seed potential is 1,000 to 1,200 lb/acre (1,132 to 1360/ha).  However, harvested yields are generally only 750 lb/acre (850 kg/ha) due to shatter before and during harvest. Crimson Clover Seeds

Stems: Stems are stout, erect, and densely pubescent. Typical height is 18 inches (45.7 cm), but variation occurs depending on cultivar. Stipules are short and rounded and stipules, like stems, are densely pubescent. Crimson Clover Stem

Leaves: Compound leaves are palmately trifoliolate, with round- to egg-shaped leaflets that are narrower near the base and finely toothed near the tip.  Crimson Clover Leaf

Root system: Crimson clover has a taproot and numerous fibrous roots that are often well nodulated. Plants normally root to a depth of 12 – 21.5 inches (31–55 cm).  Crimson Clover Roots

Other Sources for Crimson Clover Images:

Growth Habit and Production

Growth Habit and Persistence: 

Crimson clover has an erect growth habit, growing to a height of 1 to 3 feet (30-90 cm).

Physiology and growth period:

Crimson clover is a winter annual legume and does not tolerate extreme heat or cold. It grows best during the cool, humid weather that typifies the winter in mild climates. Optimal growth mean annual temperature ranges from 40 to 70°F (5-21°C) and production is greatly reduced above 80° (27°C), with an optimum germination temperature of 70°F (21°C).

Invasive Potential: If not properly managed, crimson clover may become a weed problem in some regions or habitats and may displace desirable vegetation. Categorized as mildly invasive.

Persistence: Annual (established in the fall, overwinters, and flowers in the spring)

Production Profile: 

Seasonal growth is primarily affected by temperature and precipitation. Thus, it is location dependent. Vegetative growth and forage availability by month have been stylistically drawn in various publications, with zones based on average annual temperature.  Crimson clover is shown in comparison to other appropriate species for Zone A in the southeastern region of the USA, corresponding to northern Florida to southern South Carolina (mean annual temperature > 65°F, 18°C) (Ball, Hoveland, Lacefield, 2007. Southern Forages. 4th Ed. International Plant Nutrition Institute. 322 pp. ISBN 0-962-9598-6-3).

Zone A - Forage Availability

Climate and Soil Suitability Zones

Climate

Crimson clover is native to southeastern Europe and southwestern Asia Minor and is now grown widely as a winter annual in the Southeast from Kentucky southward and from eastern Texas to the Atlantic Coast (USDA Hardiness Zones 6-9).  It is also grown as a winter annual in the Pacific North West and California, and a summer annual in the extreme northern US and parts of Canada (Hardiness Zones 3-4) (USDA NRCS, 2009).

Crimson clover has been a popular winter pasture crop in the southeastern and south-central parts of the US since the 1940’s due to its good growth under cool temperatures.  However, it does not tolerate extreme heat or cold, with optimal growth in cool, humid conditions.  Crimson clover does not tolerate drought conditions, typically requiring 30 inches (760 mm) of rainfall during the growing season.

Soils

Crimson clover will grow on soils of poorer quality than most other clovers, thriving on both well-drained sandy and clayey soils.  It does not do well in extreme cold or heat and prefers a pH range of 6.0 to 7.0 (SARE, 2012)

Crimson clover grows best on well-drained, fertile, loamy soils, and is adapted to sandy to clayey soils of moderate acidity (pH 4.8 to 8.2). It will tolerate more acidity than white and red clover, but does best when the pH is 6.0 to 7.0 (SARE, 2012).  It does not grow well on poorly-drained or highly alkaline soils.  Once established, it produces more biomass at lower temperatures than most other clover species.

 

 

Climatic tolerances are primarily cold temperature-related, with primary use zones being areas with mean annual temperature of 60°F (15°C) or warmer.

Quantitative Table:

 

July 
Max Temp (°C)

Jan 
Min Temp (°C)

Annual 
Precip.   (mm)

Soil pH

Soil Drainage
(categories)1

Soil Salinity
(mmhos/cm)

 

Low

High

Low

High

Low

High

Low

High

Low

High

Low

High

Well Adapted

   

7.0

21.3

330

  1580

5.5

7.0

MWD

SPD

0

2

Moderate

   

6.5

23.0

320

1600

6.0

8.0

MWD

WD

0

3

Marginal

   

5.9

26

310

1630

4.8

8.2

SPD

SED

0

4

1Soil Drainage categories: VPD (very poorly drained), PD (poorly drained), SPD (somewhat poorly drained), MWD (moderately well drained), WD (well drained), SED (somewhat excessively drained), ED (excessively drained).

Quality and Antiquality Factors

Quality Factors: 

Crimson clover is a high quality forage. In early spring, it may exceed 25% crude protein and 80% digestibility on a dry matter basis, decreasing to 12-14% and 60-65%, respectively at full bloom stage.

Anti-quality Factors: 

Bloat is much less likely in animals grazing crimson clover than white clover or alfalfa. Nevertheless, for use as forage, it normally is grown in mixtures with grasses to reduce this risk.

Cultivars

Cultivars:

Historically, the cultivars 'Dixie,' 'Autauga,' 'Auburn,' 'Chief,' and 'Kentucky' were developed to self-reseed and have a high proportion of hard seed. For non-irrigated fall plantings, hard-seeded cultivars are preferred.  Currently available cultivars will be identified by vendors and suppliers and characterized for their most appropriate uses and suitable climate and soil zones. 

Vendors:

Advance Cover Crops - Crimson Clover

Burlingham Seeds LLC:  http://www.burlinghamseeds.com/

Green Cover Seed - Crimson Clover

Oregro Seeds, Inc.:  http://www.oregroseeds.com/

Outsidepride.com:  http://www.outsidepride.com/

Pennington Seed - Crimson Clover

Saddle Butte Ag:  http://www.saddlebutte.com/

Silver Falls Seed Company:  http://www.silverfallsseed.com/

Smith Seed - Crimson Clover

Sustainable Seed - Crimson Clover

Territorial Seed - Crimson Clover

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