Weed Management in Fence Rows

Brent Sellers and Jason Ferrell


Weed management in fence rows and non-cropland is often as essential as it is within cropped areas. This is due to the weed's ability to distribute and establish itself rapidly. Weeds are typically prolific seed producers; therefore, they should be controlled prior to seed production. This document is intended for land owners and managers to aid in vegetation control in fence rows.

Cultural Control

Prevention is the key to avoiding weed problems. For example, if weeds are present in fence rows of cropped areas or non-cropland adjacent to cropped areas, they will eventually become a weed problem in the cropped area. Prevention methods include cleaning equipment, keeping noncrop areas mowed (preferably prior to seedhead stage), and maintaining optimum soil fertility and pH levels.

Chemical Control

Foliar applications provide more rapid control of existing vegetation, but for a shorter length of time than soil-applied. The herbicides listed in Table 2 and Table 3 will provide a list of herbicides approved for use on fence rows. Soil applications will provide residual control.

For woody species, specialized application techniques will often need to be employed for adequate control. These include basal, cut stump, and hack-and-squirt applications. For detailed review of these procedures, please reference the EDIS document SS-AGR-260, Herbicide Application Techniques for Woody Plant Control (https://edis.ifas.ufl.edu/ag245).

All labels should be read carefully because the listed herbicides may provide complete bareground control or injure non-target species.

Calibration

Always calibrate the sprayer prior to applying a herbicide. For foliar applications, the spray volume will usually range from 20 to 40 gallons per acre for light to moderate vegetation. For dense vegetation, typically 100 to 200 gallons per acre is required. Mix the suggested herbicide rate per acre in appropriate volumes of water and spray the vegetation until wet.

It is often desirable to know the length of an acre when band-spraying areas such as fence rows. See Table 1 for this information.

Table 1.  Band width and corresponding distance required to treat one acre.

Band width (ft)

Distance required to treat one acre

 

Feet

Miles

1

43,560

8.25

2

21,780

4.13

3

14,520

2.75

4

10,890

2.06

5

8,712

1.65

10

4,356

0.8

Table 2.  Herbicides for Preemergence and Postemergence Applications (Soil and Foliar Applied). Contact: Brent Sellers (sellersb@ufl.edu).

Herbicide active ingredients (Commonly used products)

HRAC

MOA

Application (rate)

Reentry (hours)

Remarks

 

 

 

 

 

Diuron

(Diuron 4L)

or

(Karmex 80)

 

5

 

 

4 to 12 qt/A

or

8 to 15 lb/A

 

12

Broad-spectrum control of many grass and broadleaf weeds. Weak on woody plants. Higher rates will provide bareground for 6 to 12 months. Can be mixed with glyphosate. Best if applied with a crop oil adjuvant.

Stalker

3–5% solution

2

imazapyr

48

Highly effective on woody plants, grass and broadleaf weeds, and cogongrass. Provides up to 1 year of soil residual activity. Can be mixed with water and applied to plant foliage or mixed with basal oil (8 to 12 oz/gal) for basal treatments. DO NOT use Stalker if desirable species are in the vicinity of the treated area. At these application rates, accidental drift or soil movement can potentially kill desirable species. Use only where total vegetation control is desirable. Sweet gum is particularly sensitive to Stalker.

Imazapyr

(Arsenal 2 and other imazapyr products)

1–1.5% solution

2

imazapyr

48

Similar to Stalker, but can only be mixed with water for foliar applications. Beware of off-site movement or desirable species in the vicinity of the treated area.

Hexazinone

(Velpar DF

or

Velpar L)

 

 

 

2.0–10.5 lb/A

or

 

2.0–8.0 gal/A

48

Provides both contact and residual control of annual, biennial, and perennial weeds and woody plants. Moisture is required to activate. Herbaceous weeds should be small if compete control is desired.

Table 3.  Herbicides for Postemergence Applications (Foliar Applied). Contact: Brent Sellers (sellersb@ufl.edu).

Herbicide active ingredients (Commonly used products)

HRAC

MOA

Application (rate)

Reentry (hours)

Remarks

dicamba

(Banvel, others)

 

4

 

1 – 4 pt/A

24

For control of herbaceous and woody broadleaf plants. Can be mixed with basal oil for stem applications. For broadcast applications, 2 pt/A is maximum rate. The 4 pt/A rate is for spot-treatment only. The addition of a surfactant for foliar applications is suggested.

Metsulfuron-methyl

(Escort XP, others)

 

2

 

0.3 – 4 oz/A

4

Effective for control of annual and perennial weeds, blackberry, kudzu, certain woody species, and Pensacola bahiagrass. A surfactant at 0.25% v/v should be included in the spray mix. DO NOT allow sprays to drift to desirable plants.

2,4-D ester + triclopyr

(Crossbow)

 

4

 

0.5 – 4 pt/A

Once spray has dried

Controls most species of unwanted woody and herbaceous broadleaf plants including annual and perennial broadleaf weeds. Does not possess residual activity. Apply to the foliage of actively growing plants. This is a low volatile ester formulation. Read Florida's Organo-Auxin Herbicide Rule for use restrictions.

2,4-D amine

(Several)

or

2,4-D ester

(Several)

4

 

2 – 8 pt/A

(3.8 lb/gal forumlations)

48

Provides foliar control of many broadleaf weeds. Ester formulations are more effective in cool weather. Does not possess a significant amount of residual activity. A non-ionic surfactant should be added for maximum effectiveness. Read Florida's Organo-Auxin Herbicide Rule for use restrictions.

Glufosinate

(Finale, Rely, others)

3–4 oz/gal (spot treat)

4–6 qt/A (broadcast)

10

 

3 – 4 oz/gal (spot-treatment)

4 – 6 qt/A (broadcast)

12

For non-selective control of grass and broadleaf weeds. No soil residual activity. Will not control woody plants. Add ammonium sulfate to the spray solution to improve herbicide performance. Do not allow grazing of treated foliage.

paraquat

(Gramoxone SL 3.0)

 

or

(Gramoxone SL 2.0)

22

 

1.7 – 2.7 pt/A

or

2.5 – 4 pt/A

24

RESTRICTED USE PESTICIDE. Controls most annual grasses and annual broadleaf weeds. Has no residual activity, and control of perennial weeds is poor. Apply to the foliage of actively growing weeds. A nonionic surfactant at 0.25% v/v should be included in the spray mix.

Triclopyr + fluroxypyr

(PastureGard HL)

1–2 pt

4

 

1 – 2 pt/A

12

Similar to Remedy. See label for specific use instructions.

Triclopyr ester

(Remedy, others)

4

 

1 – 4 qt/A

12

Controls most woody plants and many annual and perennial broadleaf weeds. Does not possess residual activity and will not control grasses. Apply in a minimum of 10 gpa. Apply to the foliage of actively growing plants. For woody plants, most effective as a basal or cut stump treatment.

glyphosate

(Roundup, others)

9

0.375–3.75 lb

4

Provides non-selective control of broadleaf and grassy weeds. Generally weaker on woody species. Does not possess residual activity. Apply to the foliage of actively growing plants. A nonionic surfactant should be added to spray mixture at 0.5% v/v if adjuvant is not pre-mixed in the product.

chlorsulfuron

(Telar XP)

 

2

 

0.25 – 3 oz/A

4

Primarily effective for the control of annual and perennial broadleaf weeds. Effective on blackberry, but more selective than Cimarron. A surfactant at 0.25% v/v should be included in the spray mix for postemergence applications.

2,4-D + dicamba

(Weedmaster, others)

 

4

 

2 – 6 pt/A

48

Controls many broadleaf weeds and brush. Does not possess a significant amount of residual activity. Spray when the leaves are full size, but have not hardened because of drought or maturity. Spray individual plants to wet with hand-gun. For larger stems (up to 3 in diameter) and hard to control species, direct spray stream to base of stems to wet the stem at the soil surface in addition to wetting foliage. Do not apply under drip line of desirable trees or adjacent to desired vegetation. For hard to control woody brush, mix Weedmaster (2.5% solution) with water (87.5%) and diesel oil (10%).