Fish Like a GIRL

Earlier this year the Lakeland Gardeners asked me to talk with them about prairie gardening, and last week I did just that. They are a really fun group and it is always a pleasure to hang around with them and to present topics in which they are interested.

In July I was asked to have an educational booth on butterflies at their Garden Fest event, which is the annual fundraiser for the club. I met a lot of fun people there, too, and we talked a lot about monarchs and milkweed.

An interesting conversation came up about milkweed, though: two different people in different situations came up after my talk to chat about problem milkweed. Common milkweed can be very aggressive as it reproduces by both seeds and rhizomes. This can make it quite difficult to control, as both of these ladies noted. Of course, they were worried about providing milkweed for monarchs, but they also had valid concerns regarding the milkweed taking over where it was not wanted.

Unfortunately, some plants with good attributes also have bad ones. That is the case with common milkweed. It can be great in a field off somewhere where it is not going to “bother anyone else,” or infringe on plants a gardener or homeowner would rather have on the landscape. It can truly take over and, as these two ladies mentioned to me, it can create a big problem in an area.

Here in the Northwoods, as many know, we are in the native range for this Monarch-attracting bully. Outside of its native range (Zones 3 to 8), it may not act as aggressively. But here, the plant is well adapted and has everything it needs to grow like crazy. As I said, because it can also grow via rhizomes, it is nearly impossible to get rid of short of burning it down. That is simply not an option in some spots, though, so gardeners are left with the long and arduous process of digging, pulling, tilling and mulching.

Mulching to kill milkweed is possible, from my understanding. 

Mulch should be applied three to four inches deep. This robs the milkweed of the sunlight it needs to grow. I have heard a few stragglers tend to crop up through the mulch, though, so gardeners should be aware of that and be ready to pull those tenacious few.

Digging up the rhizomes is one way to control milkweed.

When digging, gardeners should be sure to not cut through rhizomes and leave portions of them in the ground. They will surely re-sprout more plants, leaving the gardener to wonder what went wrong.

Tilling may be a bit easier on the back than simply digging the plants up, or even hand-pulling them. If the soil can be tilled deeply enough, it can destroy the roots. This will kill the entire plant. As with any method, though, a gardener will have to ensure there are no seed pods present, so tilling should be done before the pods emerge.

Mowing before seed pods open can help to control common milkweed as well. Mowing down plots of milkweed or part of a plot every two to three weeks before seed pods begin forming is also said to be a good way to control this aggressive plant. I have not had a lot of experience with needing to control milkweed, so I may not be the best person to ask as far as effectiveness of any of these methods, but generally, not allowing any plant to seed is usually a good tactic when looking to keep certain plants in check. Mowing is said to eventually weaken the milkweed enough that it will die. Obviously, a bagger mower would be the best option here to ensure seed pods are not redistributed. 

Once stalks no longer reproduce, it is safe to say the roots are dead or dying. But this is more of a long-term approach. However, sometimes long-term is better than an alternative such as using chemicals.

I am not one to use chemicals, but a weed killer with glyphosate has been proven to be quite effective on milkweed. That said, as most gardeners know, it is also quite effective at killing just about everything else. For that reason, I tend to stay away from chemicals. However, there are times when a person really has no choice if things get too far out of control.

I would use this tactic only as a last resort. But that is just my opinion, so that and $4 will get you a up of coffee. 

When dealing with common milkweed, gardeners should remember to wear long sleeves and pants. The sticky substance inside the milkweed stems is slightly toxic. It could lead to an itchy rash. Pets should also be kept away from milkweed, especially once it is cut. If milkweed is consumed in large quantities, it can lead to poisoning in dogs and cats. It can cause cardiovascular issues as well as gastrointestinal issues or even central nervous system symptoms

The good news, though, is that not all forms of milkweed are bullies. Butterfly milkweed, showy milkweed and swamp milkweed are great alternatives and are much better behaved. They will also attract monarchs, making them much better choices for borders and beds. 

For those suffering with common milkweed taking over areas where it is not wanted, I hope some of these tactics work well. For others looking to plant milkweed, my suggestion would be to really consider one of the other milkweeds rather than common milkweed, unless it will be planted in an area that would be acceptable for it to take over. Keep in mind that it will spread over time. Gardeners should have a plan to deal with that, should the need arise.

We can still keep plenty of milkweed on the landscape and provide for monarchs without compromising other species. 

As I told the ladies I talked to last week, do not feel bad if there is some milkweed that needs to go. It can be replaced in other areas by milkweed that is more respectful and well-behaved.

Beckie Gaskill may be reached at [email protected] or [email protected].