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5.2. SR 11-19-2007Item # 5.2. Citv of fiver MEMORANDUM TO: City Council FROM: Lori Johnson, City Administrator DATE: November 19, 2007 SUBJECT: Buckthorn Presentation -Guenter Sagan Guenther Sagan has asked to give a brief presentation to the Council on buckthorn. He has already made this presentation to the Parks and Recreation Commission. Attached is a brochure he provided with information on buckthorn. Life After'Removal of Buckthorn After buckrhom control, many sites may require replanting of desirable tree, shrub, and herbaceous speces: Removing buckthom will not only benefit the environ- ment, it provides opportunities for you to aeate wildlife habitat, re-design your landscape, and beautify an area. Do not make hasty decisions with your land, once you have removed and/or controlled buckthorn. Think about your goals and objectives for your property And `pause:' If you aze re-planting in the same places buck- thorn once grew, the soil will benefit if you wait one or two years before re-planting other trees and shrubs. Following are some alternative plantings that can be used in place of buckthorn. Check with a local nursery, extension service, Department of Natural Resources, or Depaztment of Agriculture for assistance on species rec- ommended for your azea. Here are a few ideas for replacing buckthorn: Alternative plantings for buckthorn Several species of native trees and shrubs display chaz- acteristics similaz to buckthorn. The following plants aze an example of some of the environmentally-fiiendly species available at gazden centers and nurseries. Note: The plants shown aze just a sampling of alternatives. High-bush cranberry (Viburnum trilobum) This multi-stemmed bush has lovely spring flowers and per- sistent red berries. Left unpruned, it will grow tall, but it can be pruned into a dense hedge. The European species (Vburnum opalus) is often sold in nurseries, but is invasive, and should be avoided. Nannyberry (Vaburnum lentago) Nannyberry is a tall shrub that grows in a variety of soils. It spreads gradually from a central clump, form- ing nicely shaped thicken. It has sweet, edible, blue-black fruity. (Prunes vir~iniana) Chokecherry grows in a vaziety of soil types. It develops into a tall shrub on rich, loam soils. On dry, sandy soil, it .takes on a shorter, bushier form. The bright berries make a delicious jelly and aze an important wildlife food. Grey dogwood (Corms racemosa) Commonly forms thickets at wetland mazgins, woods edges, steambanks, low spots in prairies and savannas, and along roadsides and aban- doned fields. It tolerates a vari- ety of soil types. Good for filling slopes or edges. Pagoda dogwood (Corms alternifolia) Native to rich, deciduous forests but is also commonly planted as a small ornamental tree. It prefers rich, lbam soil where the rooting. area is protected from summer heat or drought. Branches spread in horizontal layers giving ,the tree a beautifirl form. American hazelnut (Corylus amerlcana) A widespread shrub in dry to moist forests and woodlands. It grows in a variety of soil types and tolerates dry, sandy soil or gravelly slopes. In the open, it sends up many stems forming clumps. Great food and cover for wildlife. Black chokeberry (Aronsa melanacarpa) Typically grows at the margins of lakes and wetlands-places where the soil is fairly rich and moist, and where it can get partial sun. It is colonial, but not aggressive. It has attractive white flowers in early summer, and shiny black berries with lovely red foliage in the autumn. For more information: r~ Visit the Minnesota Depaztment of Natural _ urce Website at: bttp://mmm. dnrnate. mn.as/invasives/terrestriadplants/ moody/buektborn/lndex.btml Or contatt the Minnesota Depaztment of Natural Resources. (651) 296-6157 (Metro azea) or (888) MINN-DNR (elsewhere) -Thin pamphlet mar produced mitt funds provided ky ibe Msxinetotdporeit `~ StewardrHip. Program; Minnesota Foremy tt.vocattion aril MFA South ~: Chapur,~ Prairie Bntbsasiaetr, axd In>asive~Spetur Program af~a Mtnnerota Department ra'Nataral Reraprcrs. Edisdng and dessgn`ky Kathleen Preece and Brenda Cooke. Prixiied kY ProPrint, Dulush. B~ What You " JCICT Blackthorn 6eafs ant early and retains leaver late into the full, crearirag dense shade that Helps it ro out-tampete many natiDe plans. ~~ What happens when buckthorn has been planted as an ornamental shrub, a hedgerow, shelterbelt, or as a tree in your backyard? A• An impenetrable, messy thicket grows that: • Out competes our native plants for nutrients, light, and moisture. • Degrades wildlife habitat. •-Threatens the future of forests, wetlands, prairies, and other natural habitats. • Contributes to erosion by shading out other plants that grow on the forest floor. • Serves as host to other pests, such as crown rust fungus and soybean aphid. • Forms an impenetrable layer of vegetation. • Creates messy fruits that stain sidewalks and driveways. • Lacks `natural controls' like insects or disease that would curb its growth. A little history Buckthorn is not native to this country. Common or European buckthorn, and glossy buckthorn aze the two non-native invasive buckthorn species found in Minnesota. European buck- thorn was first brought to the state from Europe in the mid-1800s as a very popular hedging material. It escaped and became a nuisance plant, forming dense thickets in foresn, yards, parks, and roadsides. It crowded out native plane and displaced the native shrubs and small trees in the mid-layer of the forest where many species of -birds nested. European buckthorn is found nearly every Minnesota county, despite the fact that the sale, transport, and movement of these plane is prohibited. Glossy buckthorn, also from Europe, has been sold by the nursery trade in two different forms. The cultivar "Columnazis"is narrow and tall; the cultivaz "Aspenifolia" spreads up to 10 feet and has narrow leaves that give it a ferny texture. The Minnesota Department of Agriculture has declared Common or European'.: . ' ~ buckthorn (Rhamnus cathartics) and glossy buckthorn (Rhamnus frari®uda) as' ` restricted noxious weeds. This means that-the sale, transportarion or movement of these plants is prohibited statewide by the Minnesota Department of Agriculture, . ~ ~;,. ~. __ - Chokecherry Common Buckthorn ' . ! -.- Scientific Name Rhamnur cathartdca Franguda sinus Other Common Name European Buckthorn Fen Buckthorn, Alder Buckthorn Nursery Cultivars None Columnarir (Tall hedge buckthorn) Aspenifolia (Fernleaf buckthorn) Shape of Plant Height: 10-25 feet; oval form, Height 10-18 feet; oval form, upright upright habitat Dry azeas, like woodlands, Primarily wet azeas (bogs, marshes, riverbanks, savannahs, abandoned fields, wetlands, pond edges). It will also grow in dry roadsides. It will grow in both azeas. It will grow in both full sun and in shade. full sun and in shade. Leaves Egg-shaped with Seely tooth Oval, smooth, dark, edges: glossy, with toothless dazk green, dull to glossy edges. 3-5 pair curved leaf veins. 8-9 pair of leaf veins. Leaves slay dazk green Leaves stay green late and on the tree late into ~. into autumn. LUKE SKINNER ~ LUKE SKINNER Flowers Small, yellow-green in color. Small, seamy-green color 4 petals 5 petals produced hi month of May. produced in late May-June. Stems Buds aze opposite. Buds aze alternate. Sharp thorn at tip of the twig. NO thorn at tips of twig. Fruit Arranged in and large clusters $~d round, berry- like fruit - 1/4" diameter. Green/black color. Each fruit has J-Y JCCLLJ. Berries aze persistent. spine at dp Sub- opposite buds Round, berry-like fruit - 1/4" diameter produces less fruit than the com- mon buckthorn. Red/brown to black in color. Each fruit has 23 seeds Berries' aze not persistent. i'+ ~~~ -~-: ~ ~.,:;> _,-<;. alternate leaves 'Asplenifolia' leaf kmleaf Buck[hom bud at tip ehemate buds uckthorn! NOTE: It takes a dong term commitment to .nueesrFreldv manage buckthorn. '.lings or Small Buckthorn Plants For individual plants: If less than'/a inch in diam- eter, retatove by hand Small seedlings can be pulled and will not re-sprout. If greater than a/a inch, use a hand tool that pulls the shrub out, such as a "Weed Wrench" or "Root Talon". The "Weed Wrench" comes in four different sizes and will remove budctitom stems up to 2.5 inches in diameter. The Weed Wrench can cause some soil disturbance so extra care is needed on sensitive sites or steep slopes. Removing by hand is easier if the soil is moist. Before you pull or dig buck- thorn out of your soil, Contact Gopher State One Call (1-800-252-1166) to ensure theee aze no buried utilities in the azea. If pulling individual plants is impractical spray foliage of short buckthorn or seedlings with a herbicde. Glyphosate (one brand name is Roundup) will kill all actively growing vegetation on which it is sprayed. Triclopyr will kill broadleaf plants and will not harm grasses when applied properly. Controlling Large Buckthorn )therwise, :r cuttmg Tridopyr or 4) or !~~ ucts like Gazlon 4, treat the cut surface and the remaining bazk to the ground line. In cases where more than a few plants aze treated, add an indicator dye (avail- able where pestiddes are sold) to the herbi- cide to mark cut stumps you have sprayed:' Colored flags can also help mazk cut stumps. When buckthorn is,cut, the stumps aze easily covered and lost under cut brush. For basal stem treatment, a method that applies chemical through the bark, low volume spray applica- tions can be made with Gazlon 4 and similar oil-based products. This application method uses Triclopyr ester mixed with an oil diluent (i.e. Bark Oil Blue, kerosene or diesel oil) applied directly to the bark of buckthorn from the root collar up about 12-18 inches. This treat- ment works best on stems less than 2-3 inches in diam- eter. An ultra low volume spray wand should be used to minimize herbicide use and reduce the potential for non-tazget injury. Buckthorn treated in this fashion can be lefr standing or cut at a later date. Seed Viability Note: Buckthara seeds in the sail can remain viable far up to five years. Follow-up control of seedlings that emerge afrer initial control efforts is important on all sites. With no follow-up control, buckthorn will come back. Fire offers along-term management option in grassland or savanna cover-types. Burning will need to be done every two to three yeazs. If burnutg is no[ an option, a follow up treatment of the seedlings (pulling or spraying) is needed.