Seal Rock Garden Club

      Kudzu vs. Wild Cucumber ????

      By Sally Noack

     Common Names:  Kudzu, Japanese arrowroot

     Scientific Name:   Pueraria montana (syn:  Pueraria  

     montana var. lobata, Pueraria lobata)    

• Description:  Kudzu is a fast growing perennial vine in the Fabaceae (pea) family.  The dark green leaves alternate on the vines, have three distinct leaflets that are sometimes lobed, and are hairy on the undersides.  The taprooots can grow to be quite massive, and can weigh hundreds of pounds.  The pea-like flowers are dark pink to purple, (sometimes red), and they are often pleasantly fragrant, like grapes.  Kudzu mostly spreads vegetatively, but it also can spread by seeds that grow brown, hairy, flattened pods.  

• The plant grows a bit like English ivy (Hedera helix) or manroot (Marah oreganus, also called wild cucumber).  However, the leaves,  fruits, and flowers of these plants are quite distinct.  Ivy has small yellow-green flowers and dark purple berries.  A vining native perennial in the cucumber or gourd family (Cucurbitaceae), manroot has white flowers and green spiky cucumber-like fruits, while kudzu has purple flowers and dark brown pea-like pods.  All three plants have lobed leaves, but kudzu is the only one with 3 separate leaflets. 

•  The reason why common names can be confusing:  the following describes another plant sharing the name wild cucumber, but it is not our manroot.  "In late summer you may notice trees or shrubs festooned with crowns of white flowers that obviously are not the woody plant blooming.  Look closely and you'll notice the leaves and individual flowers look just like that of a cucumber -- this is wild cucumber or balsam-apple, Echinocystis lobata.  The name Echinocyctis comes from the Greek echinos for "hedgehog" and systis for "bladder", appropriately describing the spiny fruit.  A vining native annual in the cucumber or gourd family (Cucurbitaceae), wild cucumber is often overlooked until it it large and sometimes has engulfed the other plants it is growing on.  It occurs throughout much of North America, including all of Wisconsin.  Its native habitat is along streambeds, swamps, and moist thickets or roadsides.  As a fast-growing, warm season annual, wild cucumber grows from seed each year, germinating after the last frost."  Remember, Manroot is a perennial.  

• Similar Symptoms, Different Causes:  A friend  asks, "Why are some branches of my lilac (Syringa spp.) showing wilted leaves, dieback, and/or weakened growth, and even death?"  Here are a few answers: 1) Physical tree or shrub damage, which can be caused by lawnmowers or weed-eaters scarring the base of the plant and disrupting the flow of the nutrients to branches.   2)  The Red-breasted Sapsucker (a woodpecker) is responsible for some tree damage in our area.  Sapsuckers drill 1/4 inch holes in the bark of trees and large shrubs, especially those with thin bark, in horizontal or vertical lines.  These holes are often mistaken for insect damage by beetles and other bark boring insects.  However, insects inflict random bark damage; their holes are fewer and smaller and not in orderly rows like sapsucker holes; and there is often boring dust (frass) in or on the ground around them.  Sapsucker damage does not indicate that the tree or shrub has an insect problem as sapsuckers drill for tree sap, not insects.  (For more information and control of sapsucker damage see https://pnwhandbooks.org/node/269).   3) Insect damage by the Lilac (Syringa) - Ash borer (Podesesia syringae).  This insect resembles a paper wasp.  Adult moths overwinter in the bark, emerging from small exit holes in spring.  They mate, deposit eggs on the bark at the base of plants leaving telltale sign of frass or sawdust, and the young larvae tunnel under the bark.  At maturity the life cycle begins again.  After infestation, plants will eventually show branch dieback and weaken growth or die.  (For more information including management/control of this insect pest see https://pnwhandbooks.org/node/6938).      

• Other Gardening News:  1)  Garden Gate magazine May/June 2019 and April 2019 issues have wonderful articles and photos of butterflies, their larval caterpillar stage and their host plants, and spring gardens.  I found both issues packaged as one item at Costco.   2) Better Homes and Gardens magazine published a special issue entitled "Succulents" which has lots of great information and ideas for using  succulents in gardens and containers, etc.  3)  A note on best practices:  please try to use the least toxic control method for weeds, plant pests, and diseases.  Recently court cases regarding glyphosates (such as Round-Up) as cancer causing agents have been won against chemical manufacturers (reference: Science Magazine, May 22, 2019).  Please always follow the package directions if you use any chemical.  More information is available at your local OSU Extension Office.