Wednesday, December 19, 2012

The December Garden - Ajuga reptans "Black Scallop"

Solid, dependable and slowly spreading Ajuga reptans "Black Scallop". This photo does not accurately capture the beautiful black-purple glossiness of the leaves.

Ajuga, also known as bugleweed, has been one of the toughest and most reliable perennials that I installed this past year. My Black Scallop Ajuga reptans didn't even blink in the 100+ temps we had last summer and it is supposedly hardy down to zone 4 so I'm guessing it should sail through out zone 6/7 winters without any worries.

Ajuga comes in lots of flavors. I added a couple of green Ajuga genevensis plants a few months ago that are supposed to have lovely blue flower spikes in the summer. We shall see... So far, they're pretty mousy, but I will stay hopeful and optimistic unless proven otherwise.

Ajuga genevensis flower stalk, photo by Matt Blanc

I've also got some small variegated ajugas (I think they are "Burgundy Glow") that I planted around the same time as the genevensis. They were on sale at the nursery and quite affordable, so I thought the risk was low. They haven't grown much since, but they haven't died either, so again, staying optimistic with those. I'm hoping that if they do grow and expand, their variegated and creamy foliage will make an interesting contrast in the border.

Variegated Ajuga flower stalks, photo by Aqua-Marina

Actually, Black Scallop Ajuga is supposed to have fragrant dark blue flower spikes too. The plant had a few spikes when I planted it last spring (though I don't recall any fragrance). Hoping for a better flower show this year now that the plant has settled in.

There are reports that Ajuga reptans varieties (like Black Scallop) can be invasive, but I can't see how that could be the case. The plant expands, but grows so slowly that I feel as though it shouldn't be too hard to keep it in bounds. That said, I can see how it might crowd out any shy neighbors planted nearby.

Supposedly, the only real danger with Ajugas is crown rot, which can occur in poorly-drained soils. I definitely have drainage concerns with my heavy clay soil, but my Ajugas (especially the largest one) are planted in some fairly heavily amended landscape beds, so I hope they'll be OK.

There are lots of different kinds of Ajuga out there. Presuming that I have good experiences with the ones I've already planted, I hope to add others to my gardens down the road.

A second Black Scallop Ajuga that I planted this autumn. The rich purple coloration of the leaves comes across better in this photo.

Do you grow Ajuga? And if so, have you ever had to divide the plant? goGardenNow says you need to divide at least every three years to prevent crown rot. At least Garden Splendor says it's easy to divide simply by digging up, pulling it apart into fist-size clumps and replanting. Yardener just suggests thinning out an Ajuga planting if the bed has become overcrowded, which I suppose makes sense.

I've also read conflicting reports as to whether Ajuga is edible or poisonous. Until I figure that one out, I'll be erring on the side of caution with a look-don't-taste approach!

Will my ajugas continue to thrive in 2013? Follow their progress with free email updates!


  1. Ahhh, ajuga. I love it. I divide it. I give it away. Tough, great bloomer, great texture. I've let it naturalize in my garden, and I'm not about to reign it in.

    1. A lucky man to have naturalized ajuga in your garden! I aspire to reach such a state of glory someday :)

  2. I grow Black Scallop also and have enjoyed it, but I have found that after a while it looks no different from the more common Ajuga that I have grown for many years, which is fine by me. I also grow the tri-color, and mine hardly grows either. Two that I am trying now are Chocolate Chip and Metallica Crispa, but they're both still too small to assess. Ajuga is one of the showiest plants I have when in bloom, and I have never had one minute's trouble with it. It's a breeze to divide and as far as being invasive, that's a word I rarely use in the garden.

    1. Thanks for the comment, Dottie. I'll keep my eye on Black Scallop to see if it reverts to being a "Green Scallop" ;-) Look forward to hearing about your continuing experiments with new Ajuga varieties!

  3. I'm thinking about using ajuga to fill in between stepping stones in a shady area. I think I like the A. genevensis best.

  4. Aaron, It may be that I have gad some version of black scallop all along because my old Ajuga isn't green but very dark, and I honestly cannot tell the two apart. I think sometimes they bring out the old plants and give them cute names when they're really not all that different.


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