Blackberry: Identification and Management in Pasture and Rangeland by James M

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Blackberry: Identification and Management in Pasture and Rangeland by James M. Locke NF-SO-14-02 Blackberry (Rubus sp.) are native (usually) woody shrubs or brambles. They are members of the Rosaceae, or rose family, which includes over 600 species and developed varieties of blackberries, raspberries and dewberries in the Rubus genus. Many improved varieties of blackberry have been developed by plant breeders, and blackberry species readily hybrid- ize, so some species can be difficult to differentiate and there can be large differences between species. Due to this wide variation, this publica- tion concentrates on Oklahoma blackberry, Rubus oklahomus Bailey. Oklahoma blackberry is common in the eastern portions of Oklahoma and Texas in areas that typically receive more than 25 inches of annual rain- fall. Other blackberry species occur throughout North America, having different growth and habitat char- Blackberry flower acteristics, and potentially requiring different management strategies. Management Considerations ing or attempting to utilize forage in Blackberry management depends on infested pastures. Identification the goals for the property. The fruit Blackberry is a warm-season peren- is a favorite ingredient in jellies, pies Management Methods nial shrub with upright, arching stems. and cobblers, so it may be a desirable The stems are armed with many sharp plant in some situations. If wildlife Prescribed fire thorns or prickles. The stems can grow management is a primary goal, the A well-planned and executed pre- several feet tall and intertwine to form fruit is a valuable food source for scribed fire usually top-kills blackber- virtually impenetrable thickets. The many wildlife species. The thickets ry, but it readily resprouts from seeds leaves are alternate and palmately can provide good cover for some and buds on underground rhizomes. compound with three to five leaf- species, so maintaining blackberry Maintaining a short-interval pre- lets with serrated edges. Blackberry as part of a diverse plant community scribed burning program suppresses blooms from early spring through ear- can be beneficial. If livestock or for- blackberry and generally prevents ly summer with five-petalled, showy age production is the primary goal, it from developing into a significant white flowers. The fruit consists of an then blackberry is detrimental due problem but does not eliminate it aggregation of drupelets that change to reduced forage production and from the landscape. Prior to initiating from red to black when mature. Black- limited access to the forage that is a prescribed burning program, obtain berry reproduces from seed, basal produced. The stout blackberry prick- all necessary training and become buds on root segments and from arch- les may also cause injury and subse- familiar with laws pertaining to pre- ing ends of stems that reach the soil. quent infection to livestock travers- scribed burning in a specific locality.4

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Mechanical methods Blackberry may be managed by mowing when terrain and surround- ing tree and brush species permit. Blackberries readily resprout from basal or rhizomatous buds, so mowing does not provide long-term control. Mowing can be beneficial to remove existing top growth and allow livestock access to desirable forages. However, mowing can also leave stobbs that can contribute to foot problems. Mowing can also be used to remove old, dead canes and reduce the mass of a thicket in preparation for subsequent herbicide application. If mowing is for this purpose, do not apply the herbicide for at least 12 months after mowing.

Biological control Intensive stocking with browsing species, such as goats, can reduce blackberry density and open up areas to sunlight to allow desirable grasses to establish. Goats have a high preference for blackberry, among many other plant species, and will aggressively consume the leaves and berries. Depending on stocking rate, goats may be able to provide significant control of blackberry within three years. Considerations for using goats for blackberry management include proper installation and maintenance of goat-proof fencing, predator control, parasite management, and providing water, shelter and adequate handling facilities.

Chemical control There are several herbicides labeled Top photo: Blackberry fruit for blackberry control or suppression. Bottom photo: Blackberry leaves and stems with sharp thorns Due to blackberry plants’ extensive root systems and ability to resprout efficacy is the differences in various Spot treatments from secondary buds, more than blackberry species’ susceptibilities to The preferred application method is a one application is often necessary to herbicides. Although control recom- high-volume foliar treatment of indi- obtain satisfactory control. A com- mendations vary, the following are vidual plants or thickets. Apply 0.25% plicating factor affecting herbicide the most successful in our experience. to 0.5% triclopyr (Example: Remedy

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Broadcast treatment Broadcast treatments are not typically recommended for blackberry control due to the scattered nature of most blackberry infestations, high cost of herbicides, difficulty obtain- ing satisfactory spray coverage and inconsistent control. If a broadcast treatment is necessary due to high plant density, apply 1 to 2 quarts triclopyr (Example: Remedy Ultra®) or 3 to 8 pints triclopyr and fluroxypyr premix (example: PastureGard®) per acre in sufficient volume to provide good coverage of the foliage. Use a high-quality, non-ionic surfactant at 0.25% to 0.5% of the total mix volume. Apply from the full bloom stage in late spring through the berry drop stage in the fall. Do not apply during periods of stress from drought, frosts, Blackberry thicket heavy insect damage, etc. Do not ap- Ultra®) or 1.0% to 2.0% triclopyr and etc. The herbicidal symptoms are ply treatments within 12 months of fluroxypyr premix (example: Pasture- slower to appear, but other researchers mowing or burning of the blackberries Gard®) in enough volume to obtain have reported better long-term control as control is significantly reduced. thorough coverage of the foliage with this treatment than with other Another broadcast foliar treat- and stems. Include 0.25% to 0.5% herbicides. The better control reported ment reported by some researchers high-quality, non-ionic surfactant in by these researchers might be due to to provide suppression of blackberry the mix. Apply during the full bloom treating a different species of black- is applying 0.3 to 0.4 ounces metsul- stage in late spring through the berry than Rubus oklahomus. It should furon-methyl (example: Cimarron berry drop stage in the fall. Do not be noted that metsulfuron-methyl Max Part A®) per acre with 0.25% to apply during periods of stress from significantly damages bahiagrass, so 0.5% high-quality, non-ionic surfac- drought, frosts, heavy insect dam- this treatment should not be used tant. Thorough coverage is critical, so age, etc. Do not apply treatments where bahiagrass is a desired forage. using a high spray volume per acre within 12 months of mowing or The procedure for making a high- improves efficacy. Apply any time after burning of the blackberries because volume foliar application depends the blackberries have fully expand- control is significantly reduced. on the available equipment, and size ed leaves and are not stressed by Another high-volume foliar treat- and density of the blackberry thicket. drought, frost, heavy insect damage, ment reported by some researchers For small thickets, a small sprayer etc. The herbicidal symptoms are to have better activity on blackberry with a hand-wand mounted on a slower to appear, but some research- is applying a mix of 1 ounce metsul- four-wheeler can work quite well. For ers have reported better long-term furon-methyl (example: Cimarron larger or very dense thickets, a tractor- control with this treatment than the Max Part A®) per 100 gallons with mounted or towed sprayer with a alternatives. The better control report- 0.25% to 0.5% high-quality, non-ionic spray gun can be used to spray from ed by these researchers might be due surfactant. Thorough coverage, up to the perimeter into the thicket from all to treating a different species of black- the point of runoff, of all foliage and sides. If the thicket is so large that the berry than Rubus oklahomus. It should stems, is necessary. Apply any time spray gun cannot provide good cover- be noted that metsulfuron-methyl after the blackberries have full leaf age into the interior, it may take more significantly damages bahiagrass, so expansion and are not stressed by than one year to reduce the size of the this treatment should not be used drought, frost, heavy insect damage, thicket until it can all be treated. where bahiagrass is a desired forage.4

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There are several herbicide fits into those goals. If it is determined Extension. SS-AGR-240. Gainesville, FL. premixes or tank mixes containing that control is needed, careful plan- Ferrell, J.A., B.S. Sellers, G.E. Mac- 2,4-D, dicamba, picloram, amino- ning is required to determine the best Donald and W.N. Kline. 2009. Influ- pyralid, etc., that can be used to management strategy to match the ence of Herbicide and Application increase the spectrum of weeds severity of the infestation with avail- Timing on Blackberry Control. controlled, but it appears the major- able resources. Weed Technology. 23:531-534. ity of blackberry control is from Always read and follow label direc- Hart, S. 2000. Goats for Vegetation Man- triclopyr or metsulfuron-methyl. If tions. No discrimination is intended, agement. In: Web-based Training and there are enough other additional and no endorsement is implied for Certification Program for Meat Goat species in the pasture that need to any specific products. References to Producers. Langston University. Langs- be managed, using one of these specific products or trade names are ton, OK http://www2.luresext.edu/ mixes may be justified. In those situa- for educational purposes only. < goats/training/vegetation.html. tions, care should be taken that the Accessed 08/28/2014. triclopyr or metsulfuron-methyl rates Literature Cited Johnson, F.L. and B.W. Hoagland. 1999. are adequate to control blackberry. Anonymous. 2014. Plants of Texas Range- Rubus oklahomus Bailey. Catalog lands – Blackberry, Dewberry, Bramble. of the Woody Plants of Oklahoma: Summary Texas AgriLife Extension, Department Description and Range Maps. Okla- Blackberry is a native (usually) shrub of Ecosystem Science and Manage- homa Biological Survey. http://www. or bramble that is a normal part of ment. http://essmextension.tamu.edu/ biosurvey.ou.edu/shrub/rubu-okl. many landscapes. Its presence can plants/plant/blackberry-dewberry- htm. Accessed 08/28/2014. be positive or negative, depend- bramble/. Accessed 08/28/2014. Stevens, R.L. and C.R. Coffey. 2008. Trees, ing on the goals for the property. Ferrell, J.A. and B.A. Sellers. 2013. Black- Shrubs and Woody Vines: A Pictorial Each property manager must decide berry and Dewberry: Biology and Guide. The Samuel Roberts Noble Foun- whether or to what extent blackberry Control. University of Florida IFAS dation Inc. NF-WF-08-01. Ardmore, Okla.