The total lifetime of a rhizome and its terminal shoot is usually less than two years. Carbohydrate accumulation in rhizomes peak in late fall when above ground growth of Kentucky bluegrass slows. As temperatures become favorable for growth in the spring, these carbohydrate reserves become available for development of new shoot growth. Factors that reduce carbohydrate accumulation in the fall include high nitrogen fertilization and close mowing. Roots of Kentucky bluegrass develop from the underground nodes of rhizomes and from the basal nodes of above ground shoots, the crown.
Roots also develop at the terminal nodes of rhizomes that emerge above the soil as shoots.
Root growth is greatest in fall and spring and slows dramatically in summer. High nitrogen fertilization and close, frequent mowing greatly decrease root growth in Kentucky bluegrass. Select a blend of about 3 varieties for planting in the transition zone to increase your opportunity for success. Many of these grasses differ in their degree of susceptibility to leaf spot diseases and Fusarium blight, both being troublesome in the transition zone. A blend of several varieties will usually appear superior to a single variety since all varieties are usually not affected by adverse conditions at the same time or to the same degree.