Seasonal growth cycles of <i>Zoysia matrella</i> (L.) Merr. (manilagrass) and <i>Agrostis stolonifera</i> L. (creeping bentgrass) putting greens in Japan

Abstract The seasonal shoot and root growth of Zoysia matrella (L.) Merr. (manilagrass) and Agrostis stolonifera L. (creeping bentgrass) were pictorially analyzed in golf course putting greens in the Kanto region of Japan. Profile samples of shoots and roots were harvested seasonally, washed free of soil, and subsequent observations of tiller, root, and thatch/mat structure were recorded. The seasonal growth cycle of creeping bentgrass was determined as (1) autumn (late September through November)—roots and shoots initiated during the previous spring and summer mature; (2) winter (December through February)—nutrients are stored; (3) early spring (March through April)—growth is more active; (4) spring (May through June)—vigorous growth occurs with initiation of new shoots; and (5) summer (July to mid‐September)—parent roots and shoots senesce and are replaced by new shoots and roots. More specifically, summer growth was observed as the initiation of new shoots in June with increasing new shoot development through late July. The peak of tillering and root growth was noted as occurring from late August to early September. Most of the shoots become a single layer of new shoots from late September to early October, and autumn growth begins based on these new shoots. The seasonal growth cycle of manilagrass was determined as (1) spring (late March to late May)—parent shoots and roots senesce, and a new foundation of shoots and roots is built from those produced during the previous autumn and now in active growth; (2) summer (early June to late September)—vigorous shoot growth; (3) autumn (early October to before the first frost in December)—new shoots gradually become independent through replacement of the parent shoots; and (4) winter (first frost to mid‐March)—growth is suspended and becomes dormant. An understanding of these seasonal growth cycles can be utilized by golf course superintendents in accordance with their fertilizer and thatch management programs.