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How to Manage Pests

UC Pest Management Guidelines


Weeds growing in and around drip irrigated potted geraniums.

Floriculture and Ornamental Nurseries

Weed Classifications

(Reviewed 3/09, updated 3/09)

In this Guideline: More about weeds in loriculture and ornamental nurseries:

Weeds can be divided into broadleaf plants (dicotyledons) or narrowleaf plants (monocotyledons). Most narrowleaf plants are grasses, but this group also includes sedges such as yellow nutsedge, which are important weeds. Another way to classify weeds is by when they germinate and grow. Many common weed species are winter annuals, germinating mainly in fall, growing through winter and spring, and flowering and setting seed. Summer annuals germinate in spring, grow through summer, and flower and set seed. A few weeds complete a life cycle in 2 years and are referred to as biennials (e.g., bristly oxtongue). Some of the worst weed species (e.g., bermudagrass, creeping woodsorrel, and nutsedge) are perennials; they live for 2 years or more.

TABLE 1. Common Weeds in Floriculture and Ornamental Nurseries.
COMMON NAME SCIENTIFIC NAME
WINTER ANNUALS
bittercress Cardamine sp.
bluegrass, annual Poa annua
burclover, California Medicago polymorpha
chickweed, common Stellaria media
cudweeds Gnaphalium spp.
filarees Erodium spp.
goosefoot, nettleleaf Chenopodium murale
groundsel, common Senecio vulgaris
lettuce, prickly Lactuca serriola
mallow, little (cheeseweed) Malva parviflora
mustard, wild Brassica sp.
nettle, stinging Urtica dioica
pearlwort Sagina sp.
radish, wild Raphanus raphanistrum
rocket, London Sisymbrium irio
shepherd's-purse Capsella bursa-pastoris
sowthistle, annual Sonchus oleraceus
spurry, corn Spergula arvensis
willowherbs Epilobium spp.
 
SUMMER ANNUALS
barnyardgrass Echinochloa crus-galli
buttercup, yellow Ranunculus sp.
crabgrasses Digitaria spp.
fleabane, hairy Conyza sp.
henbit Lamium amplexicaule
horseweed Conyza canadensis
junglerice Echinochloa colona
lambsquarters, common Chenopodium album
nightshade, black Solanum nigrum
nightshade, hairy Solanum physalifolium
pigweed, prostrate Amaranthus blitoides
pigweed, rough Amaranthus sp.
pigweed, tumble Amaranthus albus
puncturevine Tribulus terrestris
purslane, common Portulaca oleracea
sprangletops Leptochloa spp.
spurge, prostrate or spotted Euphorbia (=Chamaesyce ) maculata
 
COMMON BIENNIALS AND PERENNIALS
bermudagrass Cynodon dactylon
bindweed, field Convolvulus arvensis
johnsongrass Sorghum halepense
kyllinga, green Kyllinga brevifolia
nutsedge, purple Cyperus rotundus
nutsedge, yellow Cyperus esculentus
oxtongue, bristly (biennial) Picris echioides
woodsorrel, creeping Oxalis corniculata
 
MISCELLANEOUS
liverwort Marchantia polymorpha

Growing site and production practices largely determine which weeds are likely to become problems at a site. For example, weeds commonly associated with container nursery production include creeping woodsorrel, common groundsel, lesser-seeded bittercress, and prostrate and spotted spurge. Sometimes pearlwort, liverwort, annual bluegrass, or willowherb are a problem. In field sites, weed species vary greatly but the weed spectrum can be influenced by management practices in the field and by the environment. Because of these variations, each type of production situation is addressed separately in this guideline. After the section on general methods of weed management, there are special sections for weed management in:

  • container nurseries,
  • field-grown trees and shrubs,
  • field-grown flowers, and
  • greenhouse-grown crops.

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Floriculture and Ornamental Nurseries
UC ANR Publication 3392
Weeds
C. A. Wilen, UC IPM Program, UC Cooperative Extension, San Diego County
Acknowledgment for contributions to Weeds:
C. L. Elmore, Vegetable Crops/Weed Science, UC Davis

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