Once upon a time, on the peaceful grounds of a multi-million dollar estate, there was a gorgeous expanse of expensive bluegrass sod. The king and queen loved to stroll throughout the grounds knowing that their lawns were the fairest of them all. “Darling” the kind would say, “Our yard is such a beautiful Emerald Acres green, we must reward the wizard handsomely.”

“But, what’s this?” exclaimed the queen. There on the lawn was a small light green patch; it was not at all in keeping with the beautiful emerald green grounds our royal couple had grown accustomed to. In fact, as the king and queen strolled about in horror, they noticed many more before unseen discolored spots. “Guards!” roared the king, “Find the wizard! Throw him in the dungeons and flog him if he cannot rectify our lawns from this ghastly state.”

Many eons passed, as did the age of wizardry. Still invasive grasses discolor many of our royal lawns. The worst offender is colonial bentgrass. (troublesome colonies) Bentgrass is a native grass of New England. It has been established in this region for many hundreds of years, and therefore competes successfully with desirable introduced species such as bluegrass and fescues.

Bentgrass infestation is usually identified by light green circular patches growing in the lawn. The patches green up a bit slower than most desirable grasses, but look fairly good through the first part of the growing season. Bentgrass does not like summer heat or stress from weed control treatment. It browns out without daily watering in the summer, and looks most objectionable in the fall when it takes on a fluffy unkempt aspect and a pale green and brown color.

Many theories exist as to how it invades. One possibility is contamination from sod farms. Farms that first grow bentgrass for golf courses, then bluegrass for home lawns, can leave behind small bentgrass shoots and seeds which eventually take over. Another possibility is that seeds or plant segments are moved in deer or bird droppings, or on the decks of mowers. The theory to which I subscribe is that the seeds are simply prevalent in area soils and germinate when the correct conditions present themselves. 

Bentgrass is stoloniferous, it grows on top of other grasses, eventually shading them out. This growth pattern accounts for its usually circular appearance. A keen eye can notice bentgrass at about silver dollar size. These small circles eventually coalesce into large exclusively bentgrass patches which can ruin a once beautiful and expensive lawn. Infestation is common; I would not be surprised to find some bentgrass in 50% of area lawns. Since there are no selective controls, eradication can be difficult. Bentgrass has a shallow root system and can be pulled fairly easily, though this will likely be a repetitive process. 

In the bygone era of wizardry there was nothing that could be done to control bentgrass. Recently however we have had great success using a product called Tenacity. The treatment process is a bit cumbersome as three treatments, each applied two weeks apart in the fall is needed for effective control. The bentgrass patches turn white as they die and existing desirable grasses fill in without additional seeding. If you are interested in eradicating bentgrass from your lawn just give us a call to schedule an appointment with one of our lawn technicians, a.k.a. Wizards!

Written By: Terence Boots
Massachusetts Certified Arborist
Owner: Emerald Acres Inc.