Watch for garlic mustard and giant hogweed emerging in spring

Garlic mustard rosettes in spring often have purplish stems from over-wintering.

Garlic mustard rosettes are get bigger and are easier to spot in March. In April they start bolting and forming flower stalks. Young garlic mustard plants resemble many native forest plants so make sure you have a positive ID before removing.

Noxious weed specialists can help county residents identify and control garlic mustard.

Our staff can help you with identification and control of this Class A noxious weed, which has such a negative impact in forests and native habitats. The seed bank of this plant is amazing and it is very hard to find every plant each year, ensuring that you will keep finding garlic mustard for many years where it has been in the past. Deer, dogs and other animals often track seeds to new locations and yard waste dumping can move it into parks and ravines.

In King County, look for garlic mustard especially in Seattle parks, south Bellevue parks including Coal Creek Natural Area, on the Cedar River, but also in smaller patches in places such as Covington, Black Diamond, Kenmore and Tukwila. We are sure that we haven’t found it all yet, so please let us know wherever you find garlic mustard so we can stop it from spreading further.

Giant hogweed is also emerging and will be easy to find this month, unless they are growing in a blackberry patch, in which case you’ll have to wait until May or June for the stems to reach above the brambles.

Look for raised purple blotches and stiff white hairs on hogweed stems.  The leaves are deeply cut and divided into three main parts.

Even very young giant hogweed plants have hairy stems with purple blotches.

Young hogweed leaves almost look like maple leaves when small but don’t come in pairs like maples and always have the blotchy, hairy stems.

Hogweed juice causes skin to be hyper-sensitive to sunlight and it can cause painful burns and blisters and long-lasting scars. Make sure you take care when handling hogweed and contact your local noxious weed experts to help get a positive ID and to find out the best way to control it.

Giant hogweed can cause burns so make sure to use gloves and caution when handling.

Not only does it cause burns, hogweed is a giant nuisance and is highly invasive, often spreading into ravines and out-of-the-way places where it can form large infestations without being noticed until the plants gain their full 10-15 feet. In Washington, hogweed is a Class A noxious weed. King County residents can get help from our program to control giant hogweed on their property, especially people who have challenges that make it difficult for them to do so.

King County noxious weed specialists help residents remove giant hogweed if they need assistance.

If you have questions, please feel free to contact us. If you spot garlic mustard or giant hogweed in King County, please report it as soon as possible so we can help stop these noxious weeds from spreading.