Spread Out! Tillers, Rhizomes and Stolons
by Mary Owen
hizomes, stolons and tillers are zornes and stolons, turf becomes an about the crown. The crown itself is a the lateral stems of the turf- interconnected, dynamic community tightly compressed stem. Being a R grass plant. By their growth of plants. Let's consider these parts of stem, it has nodes, internodes and, at an individual turfgrass plant spreads the turfgrass plant, how they grow, the nodes, it has meristems (growing vegetatively, providing for the initia- how they function and what factors points). These nodal meristems give tion and development of new turf- influence their growth. rise to buds. These buds are capable grass plants. This sideways or lateral of giving rise to new stems: tillers, growth thickens a turf and influences The stems rhizomes and stolons. its ability to recuperate from wear Stems store food reserves needed for and other damage. The growth of a growth. The crown is the major stor- Tillers network of rhizomes or stolons is age organ for carbohydrates. The Tillers begin to develop only after the crucial to the production of strong lateral stems, especially the rhi- grass plant has reached a certain sod. The continued development and zomes and stolons, also are storage level of maturity. This level may growth of daughter plants ensures a areas for those products of photosyn- differ by type of grass. continuous replacement of plants thesis, which, when broken down in Growing conditions and the level which naturally senesce and die, or the plant, provide energy for growth of carbohydrate reserves influence are damaged beyond growth by and development. the rate of tillering. When energy traffic, wear or other factors. To understand how lateral stems status is high, tillers are produced at Through the growth of tillers, rhi- arise, first understand some things a greater rate.
Call 1(800)817-1889 use Fast Fax #1050800 and/or Circle 105 on Inquiry Card When conditions of maturity and culminate at a single plant. Each rhi- rooting per unit area. energy level are right, a crown nodal zome continues to grow until it is bud will begin to develop into a tiller. stimulated or physically forced to Stolons This new shoot grows upward within turn upward, or until the tip is Stolons are lateral stems which begin the surrounding leaf sheaths and damaged or removed. Even when the their growth from a crown nodal bud, eventually emerges as a new shoot. tip of the rhizome is intact, new , as does a rhizome, but stay above The new tiller will develop its own shoots develop readily at the nodes ground. Like rhizomes, stolons have leaves and root system, relying less along the stem underground. The nodes and buds at the nodes capable on the parent plant for sustenance as result is a denser turf, with many of forming new shoots and roots. it matures. more shoots and more extensive Because they are above ground, When tillers are the only type of lateral stems produced by a grass, the result is a non-creeping growth habit.
Rhizomes Rhizomes are lateral stems that grow underground. When condi- tions of plant development and energy status are right, a nodal bud will begin to develop into a rhizome. This new rhizome heads downward a short way, then levels off, growing horizontally and elongating. The rhizome then turns upwards until it reaches a position near the surface. There the presence of light and possibly the change in concentra- tion of C02 causes the rhizome to stop elongating and begin the process of forming a new aerial shoot. High nitrogen levels, high temperatures and shortening days can stimulate the terminal growing point of the rhizome to turn upward. ...WhenYou In the presence of light, the leaves at the rhizome tip begin to
Call 1(800)817-1889 use Fast Fax #1060800 and/or Circle 106 on Inquiry Card
sporfsTURF· http://www.sporsturfonline.com August 2000 13 nial ryegrass and grass and tall fescue and of rhizoma- tall fescue, are not tous grasses like Kentucky bluegrass able to fill the is slowed by close mowing. spaces between Frequent mowing removes a small seedling plants as amount of leaf tissue at a time, leav- quickly as stolonif- ing the maximum leaf residual. This erous or rhizoma- allows the plant to maintain a high tous grasses. Resist level of photosynthesis and produc- the temptation to tion of carbohydrates that will be use excessive needed for new leaf tissue and amounts of seed. lateral stem growth. Turfgrass seedlings can compete with Fertility one another like Nitrogen nutrition has a profound weeds if too many impact on the development of tillers, are present, result- rhizomes and stolons. Excessive ing in thin, weak nitrogen inhibits rhizome and stolon plants. development. Stolons of heavily The thick, white rhizomes in this Kentucky bluegrass sod contrast fertilized grasses may have shorter with the darker, more fibrous roots. A network of rhizomes helps Light internodes. Phosphorous deficient to make this sod strong. Courtesy: Mary Owen Both the duration turfgrass plants have reduced tiller- exposed to light, they have the capa- and amount of light may affect the ing. Good potassium nutrition bility of forming new plants (shoots, tillering and lateral stem growth of increases the development and crown, roots, tillers and lateral turfgrass. growth of rhizomes and stolons. With stems) wherever a node may contact Most turfgrasses grown for athlet- limited fertilizer budgets, schedule the ground and form roots. New aeri- ic fields, with the exception of applications at periods conducive to al shoots also may arise at the termi- bermudagrass, will increase the tillering and lateral growth. nal if the tip of the stolon turns amoun t of tillering as the days upwards. When the terminal of a shorten. The length of light duration Moisture stolon is removed during mowing or also influences the growth habit of Irrigation timed to provide moisture is damaged, the nodes along that some grasses. Kentucky bluegrass soon after mowing lessens plant stolon are further stimulated to tillers, for example, grow more stress and results in more tillers and grow. upright when days are long and more lateral stems growth. Low moisture The growth and development of prostrate when days are short. levels decrease tillering. lateral stems varies from grass to As the amount of light available to grass, and may be influenced by a the plant decreases, photosynthesis Aeration and ~ultivation host of factors, including tempera- also decreases. With less photosyn- Cultural practices like core aeration, ture, plant stand competition, light, thesis, there are fewer carbohydrates spiking, verticutting and slicing mowing, fertility and moisture. available for plant growth and sever stolons and rhizomes. These development and activity slows in practices increase branching of these Temperature areas of high energy demand, like stems leading to the development of Cool season grasses tiller most vigor- newly growing stolons, rhizomes and many new shoots and lots of new ously when air temperatures are tillers. Therefore, the less light avail- crowns with buds ready to send out between 50 to 60 degrees Fahrenheit. able to the plant, the less lateral new tillers, stolons and rhizomes. At lower temperatures, Kentucky stem growth there will be. Tillers, rhizomes and stolons are bluegrass tends to produce more rhi- critical for turfgrass recuperation, for zomes than tillers. Low temperatures Mowing renewal of turfgrass plants from nat- may cause a more horizontal growth Close mowing of stoloniferous ural senescence and for maintenance while warmer temperatures may grasses such as bentgrass, bermuda- of a functional playing surface. stimulate more upright tillering. grass and zoysiagrass increases the Through good cultural practices, a Photoperiod, the length of day, in amount of tillering and development sports field manager will keep the combination with temperature, may of stolons. As the tips of stolons are turfgrass plants spreading out to influence the rate of tillering as well. removed by mowing, the stolons are create and maintain a great playing Warm season grasses tend to tiller stimulated to branch and to develop surface. prolifically at temperatures in the 80 new plants at each node. Mary Owen is extension educator to 90 degree Fahrenheit range. Mowing too high within the mow- and specialist, University of ing tolerance range for stoloniferous Massachusetts Turf Program. She Plant stand competition grasses will result in stemmy, puffy has served on the STMA board of Meeting recommended seeding rates turf that is easily scalped. On the directors and currently serves on the is especially important for grasses other hand, the lateral growth of Certification and Conference that only tiller. These grasses, peren- tillering grasses like perennial rye- Education Committees.
14 August 2000 sporfsTURF· http://www.sporsturfonline.com