Chapter 23

Vineyard Weed Management

Classification of Weeds

Weeds can be classified into one of three different categories: broadleaves, grasses or sedges. Broadleaf weeds have leaves that are broad, and are generally produced in pairs or multiples, have wide, flat leaves situated on a stem. Broadleaf leaves may be simple (having one leaflet, like dandelion) or compound (having more than one leaflet, like clover). Veins within the leaf give a netted appearance in most cases. Broadleaf weeds often bear colorful flowers of different sizes and shapes. Grass weeds have long, narrow leaves with veins running parallel to each other (they do not form a netlike pattern). Grasses do not have showy or colorful flowers, and leaf shapes are similar among species. In cross-section, the stems in grasses are usually round or somewhat flattened. The stems of sedges, in cross-section, are usually triangular.

Annuals

Plants that complete their life cycle in 1 year are annuals. They germinate from seed, grow, mature, produce seed and die in 1 year or less. Annuals reproduce by seed only and do not have any vegetative reproductive parts.

Biennials

Biennials complete their growth cycle in 2 years.

Perennials

Perennials are plants that live for two or more years. Perennials can reproduce by seed or vegetatively. The plant parts that allow perennials to spread without producing seeds are stolons (creeping aboveground stems—e.g., white clover and strawberries), rhizomes (creeping belowground stems—e.g., milkweed, quackgrass), tubers (enlarged underground stems—e.g., potato, yellow nutsedge) and bulbs (underground stem covered by fleshy leaves – e.g., tulip).

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