202 Montague et al.: Influence of Irrigation Volume and Mulch Arboriculture & Urban Forestry 2007. 33(3):202–209. Influence of Irrigation Volume and Mulch on Establishment of Select Shrub Species Thayne Montague, Cynthia McKenney, Michael Maurer, and Brian Winn Abstract. In many climates, irrigating shrubs during establishment is critical for long-term growth and survival. However, little research has been conducted to investigate irrigation requirements of newly transplanted container-grown shrubs. During two growing seasons, we investigated gas exchange and growth of newly planted container-grown crapemyrtle (Lagerstroemia indica ‘Victor’), forsythia (Forsythia × intermedia ‘Lynwood’), Vanhoutte spirea (Spiraea × vanhouttei), and photinia (Photinia × fraseri) transplants placed into landscape beds with and without organic mulch. After transplant- ing, plants were irrigated twice each week at the following rates: 100%, 75%, and 50% of reference evapotranspiration (ETO). In general, each year, transplants with mulch and transplants receiving 100% or 75% ETO-based irrigation had greater stomatal conductance when compared with transplants without mulch and transplants receiving less irrigation. Growth of transplants followed similar trends. However, it is key to note all transplants survived and appeared healthy throughout the growing season. Even transplants receiving 50% ETO were aesthetically pleasing and had growth acceptable for landscape situations. These findings should be useful for landscape irrigation scheduling and for irrigation managers incorporating water conservation into their landscape maintenance programs. Key Words. Forsythia × intermedia; Lagerstroemia indica; Photinia × fraseri; reference evapotranspiration; Spiraea × vanhouttei; transplant. In many communities, urban landscape irrigation is a large fraction of total water use. In fact, in arid regions of the United States, landscape irrigation is estimated to consume 40% or more of all residential water used in urban commu- nities (Ferguson 1987). Depletion of water tables (Jensen et al. 1997), poor water quality (McDaniels et al. 1998), and drought (Urbano 1990) have emphasized the need for many communities to implement water conservation programs (Sta- bler and Martin 2000; Spinti et al. 2004). However, these programs are often implemented without regard to plant wa- ter requirements. Therefore, although landscape irrigation is often required, a challenge confronting irrigation managers is to conserve water while meeting the water requirements of landscape plants (Stabler and Martin 2000). Reduced soil moisture evaporation is one of the benefits organic mulch (pine bark, pruning chips, pine needles, and so on) may produce in landscapes (Greenly and Rakow 1995; Montague et al. 2000a). Nevertheless, research on growth of woody landscape plants surrounded by organic mulch has been inconsistent. Many authors report growth of woody plants was not influenced or was reduced by organic mulch (Whitcomb 1980; Litzow and Pellett 1983; Hild and Morgan 1993; Kraus 1998; Montague et al. 2000a; Arnold et al. 2005). However, several researchers indicate woody plants ©2007 International Society of Arboriculture surrounded by organic mulch had enhanced apical (Fraedrich and Ham 1982; Hensley et al. 1988) and root growth (Watson 1988; Watson and Kupkowski 1991) when compared with woody landscape plants grown without mulch. Costello and Paul (1975) found container-grown plants of- ten fail to establish in the landscape because of rootball des- iccation and associated water stress. Rootball desiccation may occur for several reasons. First, containerized plants in a production nursery are irrigated at least once each day, whereas newly transplanted containerized plants generally have a much lower irrigation frequency (Costello and Paul 1975). In addition, there is a limited amount of available water in the rootball of a newly transplanted container-grown plant. Transplants cannot take up moisture from outside the rootball until roots establish into the surrounding soil (Wright et al. 2004). Quick root growth into the soil is critical for survival of container-grown plants (Arnold et al. 2005). How- ever, for many woody container-grown groundcover and shrub species, research on plant water use (gas exchange) has been conducted only after plants have become established in the landscape (Sachs et al. 1975; Paine et al. 1992; Staats and Klett 1995; Pittenger et al. 2001; Shaw and Pittenger 2004). Early and successful growth of a container plant’s root system into the soil after transplanting would greatly increase
May 2007
| Title Name |
Pages |
Delete |
Url |
| Empty |
Ai generated response may be inaccurate.
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success.
Downloading PDF
Generating your PDF, please wait...
This process might take longer please wait
