Randy Prostak, UMass Extention Weed Specialist, will speak at Elm Bank on Thursday, July 25 beginning at 7 pm as part of the Massachusetts Horticultural Society’s Thursdays at the Hort speaker series. While there are more than 2,200 weeds found in Massachusetts there are roughly 15 to 20 that cause repeated grievance to the homeowner in their gardens. Join Randy Prostak as he identifies the most common problems and ways to prevent or eradictate them with the least amount of detrimental impact to the environment. $10 for Mass Hort members, $15 for non members. Register at www.masshort.org.