NOXIOUS WEEDS IN SAN JUAN COUNTY FORESTS: A BRIEF GUIDE. San Juan County Noxious Weed Control Program/WSU Extension 62 Henry Rd. #26, PO Box 1634 Eastsound, WA 98245 (360) 376-3499 http://extension.wsu.edu/sanjuan/noxious/ Introduction. Forest owners and managers have a variety Noxious Weed Classes. of environmental considerations to contend Class A - consists of those noxious weeds not native to the state that are with when undertaking logging operations of limited distribution or are or woodlot management, such as protecting unrecorded in the state and that pose water quality, preventing soil erosion, a serious threat to the state. reducing wildfire risk, and providing Eradication required. wildlife habitat. The control of weeds— Class B - consists of those noxious noxious weeds in particular—probably weeds not native to the state that are doesn’t come to mind, at least prior to of limited distribution or are unrecorded in a region of the state harvest. But state law (RCW 17.10 and and that pose a serious threat to that WAC 16-750) mandates the control or region. Control may be required. eradication of certain state-listed noxious Class C – consists of any other weed species, including some that can be noxious weeds (generally considered detrimental to forests. This guide acquaints more common). May be selected for San Juan County residents interested in control at the county level. forestry practices with some of the species they might encounter, as well as some of the The forest land owner has the duty to ways these plants can be controlled. eradicate Class A weeds. Classes B and C noxious weeds designated by the state or What Is A ‘Noxious Weed’? selected by the county must be controlled (prevent them from spreading within or In the state of Washington, a noxious weed beyond that property). Selected Class C is legally defined, under RCW 17.10.10, as weeds, however, are only required to be “a plant that when established is highly controlled on designated forest lands within destructive, competitive, or difficult to a one-thousand-foot buffer strip from control by cultural or chemical practices” adjacent land uses (RCW 17.10.140 (2)). (Washington State Noxious Weed Control Yet during a single five-year period Board). following harvest for lumber, an owner of forest land must control all county-select choice of last resort for certain Class C species as well. extremely difficult species. The IVM ‘Tool Box’. Spurge Laurel Integrated Vegetation Management (IVM) Daphne laureola, Class B takes a variety of approaches to control Control Required. troublesome plants. The first step in any IVM program is to know your plants and their biology. What is the weed in question, its preferred habitat, and how does it reproduce and spread? Prevention -- truly the most economical way to deal with noxious weeds but requires awareness by the forest owner or manager. Examples include: cleaning equipment prior to entering or leaving forest land; This evergreen shrub was introduced as a using weed-free seed or mulch in garden ornamental and blooms in the revegetation; minimizing soil wintertime. If left unchecked, it may disturbance; and acquiring clean eventually take over the forest floor, aggregates for road-building. outcompeting native vegetation. Irritating Cultural – overlaps with prevention: toxins in the leaves, fruit, stems and sap planning to use non-invasive post- require the use of gloves and protective harvest plant materials and clean clothing when handling. Small plants can be mulch to suppress weed seedlings; pulled up by the roots when the ground is maintaining shade; burning. moist. A weed wrench is effective for larger Biological – can mean the use of shrubs, or use a mattock or shovel to cut the livestock to browse weeds, or roots at least two inches below the soil carefully selected insects or diseases surface. Spurge laurel spreads to new that specifically target a particular locations via birds, who consume its ripe, noxious weed species (“host black berries. The best time to control it is specificity”). in the Fall/Winter. Mechanical control with Manual/Mechanical – the use of a weed trimmer is not recommended due to hand- or power tools such as shovels, the volatilization of the toxins, which can weed wrenches, mowers or one’s cause severe irritation to exposed parts of gloved hand to control weeds. the body (eyes, skin, respiratory tract), and Chemical – herbicides, either stump-sprouting is likely. systemic or contact, ‘naturally- derived’ or synthetic, may offer a Old Man’s Beard English Ivy Clematis vitalba, Class C Hedera helix, Class C Control Recommended. Control Required. Many gardeners love English ivy as a This woody, ornamental vine has escaped ground cover, but the Washington State cultivation in a big way, especially near Noxious Weed Board considers four Eastsound, where it is engulfing cultivars to be noxious (this includes H. neighborhood forests. It can grow as much hibernica). The main task for forest lot as 5 meters in a single year, and its seeds owners is to keep the vines from climbing spread by air, water, animal, or machinery. trees, where they can produce flowers and A 0.5 square-meter area may produce as seeds that will be spread by birds to new much as 17,000 viable seeds per year sites. The sheer mass of ivy vegetation in a (WSNWCB). Engulfed trees may tree’s canopy can increase the likelihood of eventually collapse and are a significant windthrow during winter storms. Control hazard. To remove from trees, use loppers techniques are much the same as for old or hand saws to cut vines at ground level man’s beard (Clematis vitalba). Cut vines at and again several feet up (stem or root the base of all trees and several feet up, fragments can re-root if in contact with stripping them from the trunk. Ground ivy moist soil). Danger: do not pull cut vines can be cut and rolled up like a carpet, from trees due to risk of falling limbs. Use a grubbing out the roots along the way. Island shovel or Pulaski to dig up the base, or pull deer are known to browse ivy on the ground, by hand if the plant is still small. Grazers often stripping the leaves. Herbicide options like sheep can consume young seedlings and include triclopyr amine (Brush-B-Gone, young vines at ground level. A cut-and-paint Brush Killer), used full-strength for cut-stem approach with a systemic herbicide can be applications (within 5 minutes of cut), or very effective (aminopyralid, imazapyr, glyphosate (at least 41 % a.i). Caution: glyphosate), applied to the outer ring of the vines may re-root if in contact with moist cut surface (cambium) immediately after soil, and ivy can irritate the skin for some cutting, best when done in the early fall. people. English Holly lance). If you cut the tree down without Ilex aquifolium, State Monitor List herbicides, expect stump-sprouting and Control Recommended. potentially many new plants along the root system. English Hawthorn Crataegus monogyna, Class C Control Recommended. English hawthorn, yet another introduced This ornamental, non-native evergreen tree ornamental, also served as a handy or large shrub nearly made the noxious weed hedgerow for early farmers, who could keep list but was vigorously championed by the their livestock better contained due to its state’s holly growers association (it sizeable thorns and dense growth. The continues to be sold at plant nurseries). worst infestations are found in parts of San Nonetheless, the uncontrolled spread of Juan Valley, where acres of former pasture English holly is a considerable threat to are now solid hawthorn. Doug McCutcheon forests of western Washington, suppressing of the Land Bank says that this species is native vegetation at the ground and middle one of the most dangerous trees that he canopy. It can spread by seed (birds works with. Though it is still widely consuming the red berries) or vegetatively if admired for its beautiful flowers and bright the tree is damaged or disturbed red berries, which are also said to be (adventitious shoots can form from lateral medicinally useful, English hawthorn can, in roots). Small plants can be removed by heavy infestations, prevent most other land pulling or digging. Larger specimens, uses, including commercial forestry. In unless they can be removed in their entirety Europe and New Zealand, this species hosts with heavy equipment, will have to be a fire blight bacterium which can infect treated with herbicides. Cut-stump or apples and pears (WSNWCB). Like holly, frilling application with triclopyr works smaller plants can be removed when the soil well, either spring or fall. Stem injection is moist (a weed wrench or by hand). with imazapyr works even better (EZ-Ject Mowing is generally ineffective but can buy time and prevent fruit set. Some islanders called rhizomes: a single, large patch may have used heavy machinery to clear large actually be one clonal mass. If cultivated, patches, but the resultant disturbance to the Canada thistle even grows anew from root soil may produce many new seedlings, fragments as small as 1/8 inch—truly a especially if done when ripe berries are resilient species. Repeated cultivation can present. As with holly, it is best to avoid work if done every 7 to 28 days during the cutting down hawthorn as a stand-alone growing season, as can mowing or pulling treatment, given its ability to stump-sprout plants by hand when it is in the tight bud and produce new shoots from its root stage before flowering (repeat as necessary). network. In Multnomah County, Oregon, Cultural control is said to work quite well if there has been success using cut-stump or competitive forage grasses or forbs like frilling with triclopyr (amine formulation).