Weed number 7 and the also-rans

Photo by Ronald Calhoun (copyright!)

Deciding which were the worst six weeds in my garden was a no-brainer. After thinking it over for a week, I decided that there is only one other weed species that deserves special recognition. And after consulting a helpful authority, I found out its identity: nimbleweed (Muhlenbergia schreberi) a native grass with underground rhizomes that break off when you pull up the stems. The rhizomes produce new stems, making eradication very difficult.

The other garden weeds I consider also-rans. In my more intensively managed beds, there is  lambquarters, black nightshade and a bit of plantain (Plantago spp.). In the less-managed shrub borders, I struggle with two species of Cardamine, motherwort, celandine (Chelidonium majus) with the orange sap, and foxtails (Setaria). In shady edges, Impatiens pallida is abundant.

Corydalis incisa (photo by Arrowhead Alpines)

And then there are my mistakes. I thought the cute little cranesbill (Geranium (robertianum?)) growing along East Delhi might make a nice addition to my garden. Now it is competing against garlic mustard.  When Corydalis incisa didn't thrive in my rock garden, I assumed it must be a finicky plant. Wrong! You can purchase this species from Arrowhead Alpines, but be forewarned. And the alliums . . I pull them out by the hank.

And let's not forget the woodies which went unmentioned in my last post: common buckthorn, redbud (I've heard several complaints about this plant from others this season), poison-ivy, etc.

Here's an off-the-cuff top-10 list of worst weeds submitted to me by Tony Reznicek of the University of Michigan Herbarium:

1. Oxalis sp. (O. stricta, O. dillenii, and even O. corniculata)

2. Digitaria sanguinalis (hairy crabgrass)

3. Conyza canadensis (horseweed)

4. Erigeron annuus (annual fleabane)

5. Setaria sp (foxtail grass)

6. Medicago lupulina (black medic)

7. Shrub seedlings (Lonicera sp., Rhamnus sp.)

8. Tree seedlings (Quercus sp., Juglans nigra, Cercis canadensis especially)

9. Solidago sp.(goldenrods, especially S. altissima)

10. Taraxacum officinale (dandelion, mostly in my paths)