As I drive down the road the sweet smell in the air reminds me summer is here. To me nothing says summer like fresh cut alfalfa (though I do not miss throwing small squares). This year in alfalfa fields, growming along the edges and in the low lying areas, I have noticed quite a bit of yellow flowers.

This weed is Yellow Rocket (Barbarea vulgaris). A winter annual or biennial with shiny green foliage and bright yellow flowers that may reach as much as 3 feet in height.  Primarily found growing in winter small grains, forages, and pastures. 

The preference of Yellow Rocket is full sun, moist conditions, and a fertile loam or clay-loam soil. Growth is less robust at drier sites with poor soil. A little shade is also tolerated. Most vegetative growth occurs during the cool weather of early to mid-spring.

Yellow Rocket is Also Known As...

 
If you have yellow rocket it’s because your management practices have made a great environment for it. Once we know what kind of conditions it likes we can take steps to select against it.

According to Weeds and Why They Grow, Yellow Rocket (Winter Cress) likes soils very low calcium, low in phosphate, high in potash, very high in magnesium. It likes soils low in humus, soils that are anaerobic, and moist.

To reduce the vigor and eliminate Yellow Rocket in alfalfa, cut the amount of potash applied and increase the amount of SuperCal SO4. Based on the type of environment that Yellow Rocket likes this makes a lot of sense.

Muraite of potash reduces humus, calcium and soil porosity, making it less aerobic and water logged. This makes for a perfect environment for Yellow Rocket. SuperCal SO4 increases soil calcium, porosity, and sulfur levels, exactly what alfalfa needs.

Did we mention that SuperCal SO4 cost a fraction of potash? That SuperCal SO4 increases feed value of alfalfa?

What are you waiting for the countdown is on to growing high quality alfalfa, now if the perfect time to apply SuperCal SO4 and launch yellow rocket out of your fields!