Trifolium fragiferum L. ssp. bonannii (C. Presl) Soják

http://npdc.usda.gov/� most saline tolerant clover commercially available. Strawberry clover withstands flooding because the stolons have a tropic response that causes the tips to be elevated above the water level (Stevens and Monsen, 2004). It is adapted to a wide range of soil textures from loam to clay and tolerates soil pH of 5.3-8.2. It is tolerant of flooding for up to 2 months, salinity (up to 3 percent concentration), and short-term drought. It needs at least 25 inches of annual precipitation to thrive but can withstand mean annual precipitation as low as 17 inches and can tolerate mean annual temperatures of 40-50°F. (UC SAREP Online). Strawberry clover is more hardy and tolerant of harsh environmental conditions than white clover.

Establishment

There are approximately 300, 000 seeds per pound (PLANTS Database) and the seeding rate is 4 pounds Pure Live Seed (PLS) per acre. If used as a component of a seeding mix, adjust to percent of mix desired. For grazing situations, strawberry clover should be limited to 1 pound PLS per acre or 25 percent of the total seed mix (Ogle, et.al 2009). Strawberry clover seed requires inoculation in order to fix nitrogen and also requires the special strain of Rhizobia leguminosarum trifolii (Miller, et. al, 2010), (UC SAREP Online). Seedbed should be clean (weed-free) and firm and seed may be drilled to ⅛ - ¼ inch depth and light but firm soil cover or broadcast seeded followed by culti-packing or a light harrowing. On saline soils, a cover crop of barley is recommended to help establish strawberry clover (Frame, 2005). A cover crop to help establish strawberry clover is not recommended for non-saline sites. Planting should take place in late fall (dormant) or in spring. Late summer planting can be successful if there is adequate moisture (may require irrigation) and time for seedlings to establish before cold temperatures. Seed may contain up to 70 percent hard seed, so if seeding during the growing season, seed should be scarified prior to seeding. Dormant fall planting will allow natural seed scarification. Strawberry clover seedlings are easily established and grow rapidly but do not compete well with weeds (Frame, 2005). Successful stands establish from seeding and natural spread and get better over time (Stevens and Monsen, 2004).

Management

Strawberry clover is tolerant of grazing once the plants have developed strong stolons or runners. It is suited to either rotational or set-stocking and heavy grazing pressure. McDonald, 2006) recommends that a 2-4 inch stand be maintained to reduce shading by grasses so that strawberry clover persists. Close grazing (2 inch stubble height) favors clover persistence and light grazing (grass taller than 4 inches) favors grass growth (Ogle, et. al, 2008). The recommended minimum plant height to begin grazing or haying for most clovers is 4 inches and the minimum stubble height to remain at end of grazing or haying is 3 inches (Ogle, et. al, 2008). Strawberry clover can cause bloat in ruminants and increase the incidence of urinary calculi in sheep. These problems can be managed by maintaining a significant component of grass in the pasture. In waterlogged, mildly saline conditions, tall wheatgrass or ‘Newhy’ RS Hybrid wheatgrass are good companion crops and for non-saline, waterlogged conditions, tall fescue, perennial ryegrass and paspalum are suitable companion crops (McDonald, 2006). When seed is properly inoculated at time of planting, strawberry clover will fix nitrogen from N2 in the atmosphere, requiring little or no additional nitrogen fertilizer. However, legumes require relatively large amounts of phosphorus, potassium and sulphur, and will respond to additions of these nutrients as fertilizer when they are not adequately supplied by the soil. In grass-legume mixtures, it is not possible to supply the ideal combinations of elements for both grass and legume. If nitrogen is applied, the grass will tend to increase at the expense of the legume (Ogle, et. al, 2008). Strawberry clover in mixture with grass is highly suitable for hay but care needs to be taken to avoid the loss of the nutritious leaf from the clover during the curing and bailing process (Frame, 2005).

Pests and Potential Problems

Strawberry clover is susceptible to clover rot (Sclerotinia trifoliorum), clover rust (Uromyces spp.) and root-knot nematodes (Meloidogyne spp.) (Frame, 2005), (UC SAREP Online). Based on observations in California, strawberry clover may attract gophers (UC SAREP Online).

Environmental Concerns

Concerns

Concerns

Strawberry clover spreads primarily by stolons and to a lesser degree by seed and can spread into adjoining vegetative communities under ideal climatic and environmental conditions. Contact your local extension specialist or county weed specialist to learn what works best in your area and how to use it safely. Always read label and safety instructions for each control method. Trade names and control measures appear in this document only to provide specific information. USDA NRCS does not guarantee or warranty the products and control methods named, and other products may be equally effective.

Seed Production

For seed production, plant strawberry clover seed at 1 to 3 pounds PLS per acre in 20-24 inch rows. To facilitate seed production and between-row weed control, it is desirable to plant strawberry clover in spaced rows instead of a solid stand. Seed yields in the United States range from 35 – 265 pounds per acre and average 90 pounds per acre (Frame, 2005). Common strawberry clover is reported to be self-fertile but the variety ‘Salina’ is reported to be self-sterile and needs cross pollination. Self pollinated plants are less vigorous. Placing colonies of honey bees near fields will help increase seed yields (Hollowell, 1939), (McGregor, 1976). Seed is usually harvested in July by swathing to allow the seed to complete maturity and dry followed by combining. Fields should be swathed when most seed envelopes are light brown and slightly damp (from dew) to avoid seed loss due to shattering. Vacuum collection of seed has been reported to be possible but not common. Processed seed may have 40-70 percent hard seed but under proper seed storage conditions, seed will remain viable for a long time (UC SAREP Online), (Frame, 2005). Cultivars, Improved, and Selected Materials (and area of origin) ‘Fresa’ strawberry clover was developed and released by the Department of Crop and Soil Sciences at New Mexico State University in 1982. The original collection was from Turkey and was selected for its low growing habit in southern New Mexico. It remains green throughout the year, but shows some dormancy with extremely high or low temperatures (Curtis and Curtis, Inc.). ‘Salina’ was released by the California Agricultural Experiment Station in 1962. It is palatable to all classes of livestock, can tolerate periods of winter flooding and is suitable for poorly drained soils in low-lying areas (Curtis and Curtis, Inc.). ‘Palestine’, ‘Prinsep Park’, ‘O’ Connors’, ‘Grasslands Onward’ and ‘Grasslands Upward’ are strawberry clover releases developed and used in Australia and New Zealand (McDonald, K. 2006). Acknowledgement The authors acknowledge and thank the Food and Agriculture Organization of the United Nations for use of the photographs in this plant guide. Photographs were obtained from the FAO Grassland Database: http://www.fao.org/ag/AGP/AGPC/doc/gbase/Defaul t.htm

References

Curtis and Curtis, Inc. Strawberry Clover. [Online]. Available at http:www.curtisseed.com/index.cfm?show=10&mid=11&pid=10 (accessed 23July2010). Frame, J. 2005. Trifolium fragiferum L. [Online]. Available at http://www.fao.org/ag/AGP/AGPC/doc/gbase/data/pf000500.htm (accessed 26July 2010). Hollowell, E.A. 1939. Strawberry Clover. Leaflet No. 176. United States Department of Agriculture. U. S. Government Printing Office. Washington, D.C. McDonald, K. 2006. Strawberry Clover. In: Perennial pastures for Western Australia. Department of Agriculture and Food Western Australia, Bulletin4690, Perth. McGregor, S.E. 1976. Chapter 3: Clover and Some Relatives. In: Insect pollination for Cultivated Crop Plants. [Online]. Available at http://www.beeculture.com/content/pollination_handbook/strawberry.html (accessed 20 July 2010). Miller, R., Kaiser, J., Ogle, D. 2010. Legume Inoculation. USDA-NRCS. IDTN26. Boise, ID Ogle, D., St. John, L., Stannard, M., Holzworth, L. 2009. Grass, grass-like, forb, legume and woody species for the Intermountain West. USDA-NRCS. ID-TN24. Boise, ID Ogle, D., St. John, L., Cornwell, J., Stannard, M., Holzworth, L. 2008. Pasture and

Range

Seedings: Planning – Installation – Evaluation – Management. USDA-NRCS. ID-TN10. Boise, ID PLANTS Database. Conservation Plant Characteristics for Trifolium fragiferum. [Online] Available at http://plants.usda.gov/java/charProfile?symbol=TRFR2 (accessed 20 July 2010). Stevens, R. and S.B. Monsen. 2004. Forbs for Seeding Range and Wildlife Habitats. In: Restoring Western Ranges and Wildlands. USDA Forest Service Gen. Tech Rep. RMRS-GTR-136. UC SAREP Online Cover Crop Database. [Online]. Available at Http://www.sarep.ucdavis.edu/cgi- bin/CCrop.exe/show_crop_38 (accessed 20 July 2010).

Prepared By

Loren St. John, USDA, NRCS, Plant Materials Center, Aberdeen, ID Daniel G. Ogle, USDA, NRCS, Boise, ID Derek Tilley, USDA, NRCS, Plant Materials Center, Aberdeen, ID Citation St. John, L., D.G. Ogle, D. Tilley. 2010. Plant Guide for Strawberry Clover (Trifolium fragiferum). USDA-Natural Resources Conservation Service, Aberdeen, ID Plant Materials Center. Edited: 28July2010 LS; 10August DGO; 28July2010 DT; 20August2010 LS; 5August2010 JB For more information about this and other plants, please contact your local NRCS field office or Conservation District <http://www.nrcs.usda.gov/>, and visit the PLANTS Web site <http://plants.usda.gov> or the Plant Materials Program Web site <http://Plant-Materials.nrcs.usda.gov> The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer." Read about Civil Rights at the Natural Resources

Plant Traits

Growth Requirements

CaCO3 Tolerance	Medium
Frost Free Days, Minimum	180
Frost Free Days, Minimum	150
Frost Free Days, Minimum	150
Fire Tolerance	Medium
Fire Tolerance	High
Fire Tolerance	High
Fertility Requirement	Medium
Fertility Requirement	Medium
Fertility Requirement	Medium
Drought Tolerance	Low
Drought Tolerance	Low
Drought Tolerance	Low
Cold Stratification Required	No
Cold Stratification Required	No
Cold Stratification Required	No
Temperature, Minimum (°F)	-40
CaCO3 Tolerance	Medium
CaCO3 Tolerance	Medium
Anaerobic Tolerance	Medium
Anaerobic Tolerance	High
Anaerobic Tolerance	High
Adapted to Medium Textured Soils	Yes
Adapted to Medium Textured Soils	Yes
Adapted to Medium Textured Soils	Yes
Adapted to Fine Textured Soils	Yes
Adapted to Fine Textured Soils	Yes
Adapted to Fine Textured Soils	No
Adapted to Coarse Textured Soils	No
Adapted to Coarse Textured Soils	No
Adapted to Coarse Textured Soils	No
Hedge Tolerance	None
Temperature, Minimum (°F)	-33
Temperature, Minimum (°F)	-3
Shade Tolerance	Intolerant
Shade Tolerance	Intolerant
Shade Tolerance	Intolerant
Salinity Tolerance	High
Salinity Tolerance	High
Salinity Tolerance	High
Root Depth, Minimum (inches)	12
Root Depth, Minimum (inches)	12
Root Depth, Minimum (inches)	12
Precipitation, Minimum	30
Precipitation, Minimum	20
Precipitation, Minimum	20
Precipitation, Maximum	59
Hedge Tolerance	None
Hedge Tolerance	None
Moisture Use	High
Moisture Use	High
Moisture Use	High
pH, Maximum	8.4
pH, Maximum	8.6
pH, Maximum	8.6
pH, Minimum	6.0
pH, Minimum	6.0
pH, Minimum	6.5
Precipitation, Maximum	50
Precipitation, Maximum	60

Morphology/Physiology

Active Growth Period	Spring
Toxicity	Slight
Toxicity	Slight
Toxicity	Slight
Shape and Orientation	Prostrate
Shape and Orientation	Prostrate
Shape and Orientation	Prostrate
Resprout Ability	No
Resprout Ability	No
Flower Conspicuous	Yes
Fall Conspicuous	No
Fire Resistant	Yes
Fire Resistant	Yes
Fire Resistant	Yes
Flower Color	Purple
Flower Color	Purple
Flower Color	Purple
Flower Conspicuous	Yes
Fall Conspicuous	No
Flower Conspicuous	Yes
Foliage Color	Green
Foliage Color	Green
Foliage Color	Green
Foliage Porosity Summer	Porous
Foliage Porosity Summer	Porous
Foliage Porosity Summer	Porous
Foliage Porosity Winter	Porous
Bloat	Medium
Resprout Ability	No
Active Growth Period	Spring
Active Growth Period	Spring
After Harvest Regrowth Rate	Moderate
After Harvest Regrowth Rate	Moderate
After Harvest Regrowth Rate	Moderate
Bloat	High
Bloat	High
Nitrogen Fixation	Medium
C:N Ratio	Low
C:N Ratio	Low
C:N Ratio	Low
Coppice Potential	No
Coppice Potential	No
Coppice Potential	No
Fall Conspicuous	No
Lifespan	Moderate
Height, Mature (feet)	0.5
Height, Mature (feet)	1.5
Known Allelopath	No
Known Allelopath	No
Known Allelopath	No
Leaf Retention	No
Leaf Retention	No
Leaf Retention	No
Foliage Porosity Winter	Porous
Lifespan	Short
Lifespan	Short
Low Growing Grass	No
Low Growing Grass	No
Low Growing Grass	No
Nitrogen Fixation	High
Nitrogen Fixation	Medium
Growth Rate	Rapid
Height, Mature (feet)	0.5
Foliage Porosity Winter	Porous
Foliage Texture	Fine
Foliage Texture	Fine
Foliage Texture	Medium
Fruit/Seed Color	Brown
Fruit/Seed Color	Brown
Fruit/Seed Color	Brown
Fruit/Seed Conspicuous	No
Fruit/Seed Conspicuous	No
Growth Form	Stoloniferous
Growth Form	Stoloniferous
Growth Form	Stoloniferous
Growth Rate	Moderate
Growth Rate	Rapid
Fruit/Seed Conspicuous	No

Reproduction

Fruit/Seed Persistence	No
Propagated by Tubers	No
Propagated by Tubers	No
Propagated by Tubers	No
Propagated by Sprigs	No
Propagated by Sprigs	No
Propagated by Sprigs	No
Propagated by Sod	No
Propagated by Sod	No
Propagated by Sod	No
Propagated by Seed	Yes
Propagated by Seed	Yes
Propagated by Seed	Yes
Propagated by Cuttings	No
Propagated by Cuttings	No
Seed per Pound	299371
Seed per Pound	299371
Seed per Pound	299371
Seed Spread Rate	Slow
Seed Spread Rate	Slow
Seed Spread Rate	Slow
Seedling Vigor	Low
Seedling Vigor	Low
Seedling Vigor	Medium
Small Grain	No
Small Grain	No
Small Grain	No
Vegetative Spread Rate	Moderate
Vegetative Spread Rate	Moderate
Vegetative Spread Rate	Moderate
Propagated by Corm	No
Propagated by Cuttings	No
Bloom Period	Early Summer
Bloom Period	Late Spring
Bloom Period	Spring
Commercial Availability	Routinely Available
Commercial Availability	Routinely Available
Commercial Availability	Routinely Available
Fruit/Seed Abundance	High
Fruit/Seed Abundance	Medium
Fruit/Seed Abundance	Medium
Fruit/Seed Period Begin	Spring
Fruit/Seed Period Begin	Spring
Fruit/Seed Period Begin	Summer
Fruit/Seed Period End	Summer
Fruit/Seed Period End	Summer
Fruit/Seed Persistence	No
Fruit/Seed Period End	Summer
Propagated by Corm	No
Propagated by Corm	No
Propagated by Container	No
Propagated by Container	No
Propagated by Container	No
Propagated by Bulb	No
Propagated by Bulb	No
Propagated by Bulb	No
Propagated by Bare Root	No
Propagated by Bare Root	No
Propagated by Bare Root	No
Fruit/Seed Persistence	Yes

Suitability/Use

Palatable Browse Animal	Medium
Palatable Graze Animal	High
Palatable Graze Animal	High
Palatable Graze Animal	High
Palatable Human	No
Palatable Human	No
Palatable Human	No
Post Product	No
Post Product	No
Post Product	No
Protein Potential	High
Protein Potential	High
Protein Potential	High
Pulpwood Product	No
Pulpwood Product	No
Pulpwood Product	No
Veneer Product	No
Veneer Product	No
Veneer Product	No
Lumber Product	No
Berry/Nut/Seed Product	No
Berry/Nut/Seed Product	No
Berry/Nut/Seed Product	No
Christmas Tree Product	No
Christmas Tree Product	No
Christmas Tree Product	No
Fodder Product	Yes
Fodder Product	Yes
Fodder Product	Yes
Palatable Browse Animal	High
Lumber Product	No
Lumber Product	No
Naval Store Product	No
Naval Store Product	No
Naval Store Product	No
Nursery Stock Product	No
Nursery Stock Product	No
Nursery Stock Product	No
Palatable Browse Animal	High

Trifolium fragiferum L. ssp. bonannii (C. Presl) Soják