Viper Balansa Clover

Quick to establish and early to bloom, Viper provides early nutrients and feed for both soil and animal health. Great for pollinators too!

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Variety Summary

Viper balansa clover is an early maturing, high-yielding annual legume able to tolerate a wide range of soils. It produces significant amounts of nitrogen, ideal for cover crops and animal feed. Viper may be cut for stored forage or grazed. It is highly digestible, and adapted to rotational grazing. Viper can also take close grazing, even when young. Abundant flowers attract pollinators while hard seed production provides natural reseeding. Early trial results indicate Viper also has moderately good winter hardiness.*

*Viper has been tested in the United States since 2017. While we have much to learn about it, so far, Viper has shown moderately good winter survivability in PA, OH, & IN, along with early growth and vigor.

Close up of Viper Balansa plant showing its growth pattern
Viper balansa clover in a research trial

Grows Like No Other

Viper is quick to germinate, with better vigor/earlier growth than some other balansa varieties. Initially, Viper forms a small, multi-branched rosette emerging from a single, deep taproot. Under a grazing regime, Viper will remain prostrate. However, allowed to grow, Viper’s stems will eventually turn upright, forming a multi-branched hollow stem with copious amounts of plant mass up to three feet high.

As the plant matures, it will continue to grow and produce blossoms that are very attractive to pollinators. Allowed to seed, Viper is capable of producing large amounts of regenerative hard seed viable up to three years.

Tremendous Tolerance

Viper balansa performs well in an extremely wide range of soils, tolerating pH levels from 4.5-8.3 and able to survive in waterlogged soils and short periods of flooding.

A Multipurpose Clover

Cover Crop

Viper’s nitrogen production, soil-building root structure, and extensive biomass production make it a top choice for adding to a cover crop mix. Viper can be combined with grasses, brassicas and other legumes. Balansas have been shown to fix over 100 lbs. N/acre per year. Viper, in particular provides that N earlier, due to its earlier maturity.


Viper can be frost seed or broadcast into existing pastures to boost protein levels of forage, while contributing nitrogen to other crops. With excellent digestibility and protein levels in the upper 20’s, Viper is an ideal component in a small grain/grass/legume sward that can be harvested by grazing, hay or silage. Viper can take close grazing, even when young. Use with other non-legumes will reduce bloat potential.


Viper produces abundant flowers. Honeybees and other pollinators love it and so do the deer!

Yield Data

Mississippi State University

Cover Crop Trial

Starkville, MS



VarietyYield (DM/AC)Total Yield

*Statistically equal to top scoring variety.

Planted: 10/18/19.

Fertilizer: 100 lb/A of 0-0-60, Herbicide: 5 oz/A of Pursuit® (imazethapyr)

Soil type: Marietta Fine Sandy Loam

Cover Crop Performance

In the October of 2019, researchers with the University of Tennessee planted extensive cover crop trials in three Tennessee locations – Knoxville, Spring Hill, and Milan. In addition to assessments of nitrogen content and release, assessment were conducted for ground cover, biomass and height. The data below reflects averages of all three sites. Site-specific data and complete results available upon request.

University of Tennessee

Biomass, Canopy Cover, and Height

Three Location Average



VarietyBiomass (Tons DM/A)Canopy Cover (%)Height (in)

See complete trial here.

University of Tennessee

Nitrogen Content/Estimated Nitrogen Release

Three Location Average



VarietyBiomass (Tons DM/A)Total Nitrogen (%)Est. N Released: April Termination (lbs/ac)Est. N Released: May Termination (lbs/ac)
 AprilMayAprilMay2 wks.4 wks.12 wks2 wks.4 wks.12 wks

See complete trial here.

Trial Data

Winter Hardiness

Early trial results indicate Viper also has moderately good winter hardiness. Viper has been tested in the United States since 2017. While we have much to learn about it, so far, Viper has shown moderately good winter survivability in PA, OH, & IN, along with early growth and vigor.

Early Flowering

In both the South and the North, we have seen Viper demonstrate abundant growth, early flowering and extensive pollinator activity.

More To Come

As part of our continued research efforts, Viper was recently planted at numerous locations, with new data anticipated soon.

Planting Instructions

Before You Plant

Viper balansa can grow over an extremely wide range of soils tolerating pH levels from 4.5-8.3. It is quite tolerant of waterlogged soils and can even withstand short periods of flooding. For best performance, saline and drought soils should be avoided. Seeding into deep, sandy soils or soils prone to drought is not recommended.

For optimal performance, conduct a soil test and follow the recommended lime and fertilizer recommendations. In established pastures, remove excess forage through grazing or late season haying. This will help ensure successful seedling emergence and establishment. Reduce weed population prior to planting. Be aware of herbicide carryover/residual of chemicals applications prior to planting.

Planting Method

Plant into a prepared/firm seedbed by broadcast or drill. Planting too deep may lead to poor establishment or stand failure. Cultipacking or dragging before and after seeding helps create a firm seedbed.


Viper needs to be inoculated with Rhizobium leguminosarum biovar trifolii. This is best achieved with Nitro-Coat®.

Seeding Rate

Pure Stand
5-8 lbs/ac
Mix with Grasses
3-5 lbs/ac
Established Grass Pasture
3/4 lbs/ac

Planting Dates

Lower Southern USA
Late fall
Upper Southern USA
Mid-late fall or early spring
Northern USA
Early fall or early spring (frost seeding works well)

Planting Map

Planting Depth


Optimal pH



Apply lime, potassium and phosphorus per soil test results. No nitrogen is necessary.