Competition Between Established Tree Roots and Newly Seeded Kentucky Bluegrass¹

Abstract

Landscape situations frequently are such that trees may be well established when an attempt is made to establish turf. This occurs when renovating an old lawn, changing type of turf, or where new subdivisions are located in areas of established trees. This study was initiated to assess the effects of established silver maple (Acer saccharinum) and honey‐locust (Gleditsia triacanthos L.) roots on newly seeded Kentucky bluegrass (Poa pratensis). A connecting pot technique was used to maintain nearly uniform light intensity over tree‐shaded pots with or without tree roots. Silver maple and honeylocust roots established prior to seeding of common Kentucky bluegrass had a highly significant effect on growth of bluegrass, but the bluegrass had no significant effect on tree roots. Dry weight of foliage, sod and root yields, and root/sod ratios were reduced by presence of tree roots. Penetration of bluegrass roots into the main soil mass was restricted by silver maple roots. A mat of bluegrass roots about 0.95 cm (⅜ inch) thick was easily lifted from the soil containing tree roots. Established tree roots reduced the number of bluegrass plants established from seed, but had no effect on tiller production. It is hypothesized that biochemical inhibition (allelopathy) may be involved.

Low-input Performance of Zoysiagrass (Zoysia spp.) Cultivars Maintained under Dense Tree Shade

“…Tree shade represents, arguably, the most stressful of these environments for the establishment and persistence of turfgrass, because it simultaneously reduces light intensity and alters the red:far-red ratio of sunlight (Bell and Danneberger, 1999;Wherley et al, 2005). Changes in microclimate (Giesler et al, 2000) and root competition (Whitcomb, 1972;Whitcomb and Roberts, 1973) associated with tree shade further exacerbate the situation. Shade-avoidance responses by turfgrasses often culminate in undesirable morphological changes, including increased leaf elongation, internode length, and plant height as well as decreased tillering and root:shoot ratio (Shnyder and Nelson, 1989;Tan and Qian, 2003;Wherley et al, 2005;Winstead and Ward, 1974).…”

Impacts of Altered Light Spectral Quality on Warm Season Turfgrass Growth under Greenhouse Conditions

“…T urfgrass growth and development under shade is inhibited by reduced photosynthesis (Jiang et al, 2004; Miller et al, 2005), increased disease pressure (Beard, 1965; Vargas and Beard, 1981) due to extended morning dew duration (Dudeck and Peacock, 1992; Williams et al, 1996), reduced carbohydrate production (Bunnell et al, 2005b, 2005c), tree root competition (Whitcomb, 1972; Whitcomb and Roberts, 1973), and reduced lateral stem growth (Beard, 1997). Another factor limiting turfgrass growth and development under shade are various types of filtered light.…”

Quality and Yield Response of Four Warm‐Season Lawngrasses to Shade Conditions1

“…Plant vigor and hardiness are decreased and succulence is increased by shade (6). Tolerances to temperature extremes, moisture stress and wear are lessened, and susceptibility to pests is increased in shad,~d plants (13,14). Chlorophyll content is also increas,~d while respiration, transpiration rate, carbohydrate/N ratio, and osmotic pressure decrease in turf grown in low amounts of light (3).…”