Dogfennel

Description

Dogfennel is a perennial weed common to turf, roadsides and container plants. Depending on the management practices for the site, dogfennel can grow to be a very tall plant (exceeding 3 feet in height), or may reach maturity as a short plant (less than 6 inches). The finely dissected leaves of the plant make it easy to identify, and when crushed, the leaves and stems have a very distinct odor that is slightly sour and musty. The stems of dogfennel are soft and easily broken when young, but become very tough and woody as it ages. In addition, the stems are very conspicuously hairy, especially when young, but leaves are always hairless. Dogfennel could be confused with several other common turf weeds, including horseweed and mugwort. However, mugwort has very distinctive white wooly hairs on the underside of each leaf, and horseweed has elongated leaves with few to no serrations, and dogfennel has highly divided leaves.

Dogfennel, perennial weed.Figure 1. Dogfennel.

Cultural Control

Perennial broadleaf turf weeds are capable of living more than two years. They thrive in weak, thin turf; golf fairways and roughs; home lawns; playfields; and industrial grounds. Proper turf maintenance is the key to control of this weed. First, select adapted turfgrass cultivars for your area and then properly fertilize, mow, and water to encourage dense growth.

Chemical Control

Herbicide and Formulation Amount of Formulation per 1,000 sq ft Amount of Formulation per Acre Pounds Active Ingredient per Acre
Preemergence and Postemergence Control
mesotrione, MOA 27 (4 SC) (Tenacity) 0.092 to 0.183 fl oz 4 to 8 fl oz 0.125 to 0.25
Precaution and Remarks: Use on residential turf, golf courses (not greens) and sod farms for pre- and postemergence weed control. Tolerant turfgrasses include St. Augustinegrass, centipedegrass, tall fescue, fine fescue, Kentucky bluegrass, and perennial ryegrass. Add a nonionic surfactant and repeat application after 2 to 3 weeks for improved postemergence control. Tank mix with prodiamine 65 WG for extended preemergence grassy weed control. Can be applied at seeding to all tolerant grasses except fine fescue. After turf germination, wait 4 weeks or until turf has been mowed twice before making a postemergence application. Also controls henbit, chickweed, dandelion, white clover, Florida betony, Florida pusley, ground ivy, oxalis, wild violet, creeping bentgrass, and yellow nutsedge.​
[sulfentrazone + prodiamine], MOA 14 + 3 (4 SC) (Echelon) 0.184 to 0.826 fl oz 0.5 to 2.25 pt 0.25 to 1.125
Precaution and Remarks: For use in residential and institutional lawns, athletic fields, sod farms, golf course fairways and roughs, roadsides, utility right-of-ways, railways, and industrial areas. Apply to turf following a second mowing if a good root system has been established. Apply up to 12 fluid ounces per acre to bentgrass at 0.5 inch or higher, fine fescue, and perennial ryegrass. Apply 18 to 24 fluid ounces per acre to perennial bluegrass, tall fescue, and all warm season grasses except St. Augustinegrass (do not apply) and bermudagrass (apply 18 to 36 fluid ounces per acre). For sod production, apply 6 months after establishment, and do not harvest within 3 months. Do not apply with adjuvants or surfactants. [Sulfentrazone + prodiamine should not be applied to cool-season turf with N-containing fertilizers unless some short-term discoloration is tolerable.​

Species Data

  • GROWTH SEASON / LIFE CYCLE
    • perennial weed
  • GROWTH HABIT
    • upright, may reach more than 6 feet (2 m) in height
  • LEAFLET NUMBER
    • one
  • LEAF MARGIN
    • deeply lobed, with serrated edges
  • LEAF HAIRS
    • none
  • LEAF VENATION
    • pinnate
  • LEAF ARRANGEMENT
    • lower leaves may be opposite, but upper leaves are alternate
  • ROOT TYPE
    • fibrous
  • FLOWER COLOR
    • inconspicuous, greenish-white

Written By

Photo of Charles Peacock, N.C. Cooperative ExtensionDr. Charles PeacockProfessor and Extension Turfgrass Specialist (919) 515-7615 charles_peacock@ncsu.eduCrop & Soil Sciences - NC State University
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This Extension factsheet can also be viewed at:
https://content.ces.ncsu.edu/dogfennel