By Gerry McCabe

I transplanted my Dwarf Mountain Laurel recently. Kalmia latifolia, or “Elf,” as she is named, was doing poorly in her pre-selected home base of two years with browning leaves and dead apical growth. Primarily an “understory” shrub (growing within the dappled shade of larger deciduous trees) I had carefully selected a locale on the northeast side of the house between two PJM Rhododendrons.

Whether it was that hot mid-morning sun or the incredible drought of last summer, Elf was looking poorly, to the point of certain demise. So to avoid a certain catastrophe to one of our state flowers, I decided a move to a more sheltered spot was in order, if only to let her expire in peace and dignity.

As I dug her from the ground, I noticed her roots were rather sparse and globular in form, not at all what you would expect from a shrub growing for two years. On closer examination I noticed her foliage was evenly notched along the edges, as if a little mouth had come and taken perfect crescent-like bites out of the leaves.

Every leaf had at least one chomp out of it, leaving a brown scar in the dark green blade. Hmm… I know of only one little bugger which could be the culprit: the Black Vine Weevil. This insect is normally known to attack rhododendrons, yews and hemlocks but way down there in the fine print, mountain laurels can also be a host. 

The Black Vine Weevil is a non-flying, chewing insect that has usually found its way to the plant root ball from the nursery where it was potted or bagged. It is imperative to examine plants thoroughly before purchase. If any “bite” marks are noted on the leaf edges, notify the grower immediately and do not buy.

To control this pest it is important — as with any pest control — to know its life cycle and when it will be most vulnerable. The weevil over winters in grub form deep in the ground around the bush or as adults in the scattered debris. The C-shaped white grubs have a brown head and tend to wake up in late April and start their voracious root feeding.

The adults, who are always female, lay eggs around the base of the plants. These eggs hatch into grubs in ten days, where they feast on the roots of the plants and then pupate. The adults, which emerge, are 3/8 inch long, black with yellow hairs on their back and wingless.

Now here is the eradication clincher: Since the grubs are so deep in the soil, they are impossible to reach with a control. The adults cannot fly and feed at night, scurrying back into the soil at the first sign of dawn’s light. Most adult weevils appear during June and July.

If you suspect these critters, go out an hour after dark some summer night, creep up to the shrub and quickly flash the flashlight into their tiny unsuspecting faces. If you see these black bugs running down the stem for cover then you know what you have got and what you have to do.

Use insecticides with respect and caution. Always read the labeled instructions. More is never better.

What you need to do to control this insect is apply a soil drench during the day, when the adults have retreated back to the soil for an after-dinner rest. This will need to be done at three-week intervals throughout the summer.

Trying to be as organic as I can with my gardening I, too will occasionally resort to the least dangerous form of control available. Sometimes this is an insecticide, but first I will always take into account my personal value of the plant. If I can live without it, I will destroy it before applying any killer.

Visit a reputable garden center and ask questions about an effective insecticidal drench for this critter. Once you know what you have it is easy to take care of the problem.

(When she isn’t tending to her garden at home, Gerry McCabe spends some of her time continuing her gardening education at Naugatuck Valley College in Waterbury. Gerry can be reached at TNGCATS@aol.com.)