In general, the weeds that are problematic for tree fruit growers are grasses and perennial broadleaf weeds. Management strategies are dramatically different than in other commodities; the most common conventional management strategy is grass drive lanes between tree rows with herbicide used to remove weeds within the tree row. Row covers, mulches, organic pesticides such as limonene, mowing, and tillage are non-chemical management options, each with its own benefits and drawbacks. Each management system also impacts tree root growth and fruit yield. As our climate shifts towards more intense rain events with significant dry spells between rains over the summer, the impacts of weed management strategies on soil moisture may become increasingly important for unirrigated orchards.
Photos below link to species specific pages for identification and management of the most problematic species. Text below provides links to other problem species available from extension services around the US.
Bindweeds: field and hedge bindweed
Bull thistle (Cirsum vulgare)
Canada thistle (Cirsum arvense)
Curly dock (Rumex crispus)
Dandelion (Taraxacum officinale)
Japanese knotweed (Polygonum cuspidatum)
Horsenettle (Solanum carolinense)
Horseweed (Conyza canadensis)
Yellow nutsedge (Cyperus esculentus)
Poison Ivy
Broadleaf dock (Rumex obtusifolius)
Broadleaf dock identification resources available through the University of Missouri Weed ID Guide.
Broadleaf dock management discussed by Whatcom County Extension in Washington State in a presentation on identification and management of broadleaf dock.
Goldenrod (Solidago) and fleabane (Erigeron) species
New York has thirty-eight goldenrod species and ten fleabanes, but only a few of them are weedy. The most common are found in our guide to spring rosettes: Canada goldenrod and annual fleabane. Goldenrod control is discussed in the Goldenrod page of the Bugwood Wiki; fleabane control is discussed by the Penn State Extension staff in their Lawn and Turfgrass resources, in a post on orchard herbicide trials by extension staff at the University of California, and in an article on spring weed control in hay and pasture from Penn State University Extension.
Yellow toadflax (Linaria vulgaris)
Identification and control of yellow toadflax available through the University of Wisconsin Horticulture Extension’s website.
Sowthistles (Sonchus spp)
New York has five sowthistle (Sonchus spp) species, three of which are common weeds: annual sowthistle (Sonchus oleraceus), perennial sowthistle (Sonchus arvensis), and spiny sowthistle (Sonchus asper). Spiny sowthistle is an annual orchard weed; perennial sowthistle is a prerennial weed of meadows, pastures, disturbed lands, and cultivated crops; annual sowthistle is more often found in wetter soils in disturbed areas and gardens. See the links in the sentence above for identification and management options from the Bugwood Integrated Pest Management Wiki.
References
Arthur Agnello, Kerik Cox, Jaume Lordan, Poliana Francescatto, and Terence Robinson. 2017. Comparative Programs for Arthropod, Disease and Weed Management in New York Organic Apples. Insects (8), 96, 20p; doi:10.3390/insects8030096 .
Shengrui Yao , Ian A. Merwin, and Michael G. Brown. 2009. Apple Root Growth, Turnover, and Distribution Under Different Orchard Groundcover Management Systems. HortScience 44(1), 168-175. DOI: https://doi.org/10.21273/HORTSCI.44.1.168.
Deborah Breth and Elizabeth Tee. 2013. New Findings in Weed Control in Young Apple Orchards. New York Fruit Quarterly, 21 (4), 13-18.
Pennsylvania State University. Integrated Weed Management: Weed Scouting for Fruit Production. Video.
Images included from Invasive.org. Offers an extensive online library of images for invasive and exotic species of North America.
Image also included from flickr.com.