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Garlic Mustard, Rhubarb, Borer Control, and Garden Planting
By John Fulton

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[May 12, 2015]  Garlic Mustard - Garlic mustard is a cool season biennial herb with stalked, triangular to heart-shaped, coarsely toothed leaves that give off an odor of garlic when crushed. First-year plants appear as a rosette of green leaves close to the ground. Rosettes remain green through the winter and develop into mature flowering plants the following spring.

Flowering plants of garlic mustard reach from 2 to 3-1/2 feet in height and produce button-like clusters of small white flowers, each with four petals in the shape of a cross. We haven’t reached the temperature threshold for the flower stalks to elongate, but that will come shortly.

Control of garlic mustard is somewhat difficult. Seeds can remain viable for at least five years in the soil. Small amounts can be pulled up (including the roots). Garlic mustard can re-grow from root material. For herbicides, glyphosate (Roundup) is the most often recommended. Remember glyphosate kills broadleaves and grasses it gets on. There has been some success with 2,4-D LV400 where there aren’t concerns with other understory plants. Very large patches have been controlled with fire, but that completely destroys the understory of timbers. Remember to monitor areas for at least five years due to the seed dormancy period. Some action at this early time may help prevent larger problems down the road. It is much easier to control small patches than large ones.
 


Rhubarb

Rhubarb is a fruit people crave to start the season. As reminders, the first year of establishment, you shouldn’t harvest at all. The second year you can have one or two weeks of harvest. After the second year, you can harvest eight to ten weeks. Pull the stalks, and don’t remove more than a third at any one time. The old adage of “don’t harvest in any month with an “r” in it is also good advice.

The appearance of seedstalks is a common problem. This tends to happen with cheaper plants grown from seed, overcrowding, plants that have begun declining and need to be divided and re-planted, or plants suffering from low fertility. When seedstalks do appear, simply cut them off at the base of the plant. The production of seedstalks tends to make the leaves and petioles smaller.

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 Borer Control

Here is a listing of common borers and their control times: Ash borers (early June and early July), Bronze birch borer (mid May and repeat two times at two week intervals), Dogwood borer (mid May and mid June), Flatheaded apple borer (late May and repeat in three weeks), Lilac borer (early June and early July), Locust borer (late August and mid September), Mountain ash borer (early June and mid July), Peach tree borer (mid June and mid July), Viburnum borer (early June and early July), and Zimmerman pine moth (April or August). The Emerald ash borer, although not confirmed in our area at this time, has a control time in Michigan beginning mid-May and runs through mid-July. The product of choice for many borers is now permethrin or bifenthrin. Imidicloprid, as a soil treatment, has some control of certain borers, but can’t be used on any fruit trees. Sevin (carbaryl) is the product of choice for most fruit trees, and is applied directly to the trunk.

Garden Planting

We are approaching the planting time for warm-loving vegetables, which is May 10 through June 1. Of course, the weather has been slow to cooperate this year. Warm season vegetables include Lima beans, cucumber, eggplant, melons, pepper plants, sweet potato slips, pumpkins (wait until Father’s Day for jack-o-lantern pumpkins), and squash. You can also put out successive plantings of snap beans, beets, carrots, and sweet corn to extend the season.

[By JOHN FULTON, COUNTY EXTENSION DIRECTOR SERVING LOGAN, MENARD, AND SANGAMON COUNTIES]

 

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