They're very susceptible to crown rot if their isn't good drainage. I'm not sure if they're fully hardy to zone 3/4.

Well, you're on the tail end of the zone tolerance. 3 is the lowest zone they'll grow in. Maybe it just got too cold and wet?

Deffinitely not wet, but with no snow the cover was sparce. Probably got too cold, even though it was a pretty warm winter by and large.

MINE ALWAYS LOOK RATTY IN EARLY SPRING, BUT GIVE IT A MONTH AND ALL IS WELL AGAIN.

Yeah I have seen ratty, but this is really GONE! I have one small sprout in what was a two by 15ft area. Deeper in the garden I have spots where it survived. Oh well I had heard so much about it being so invasive I was debating how smart I was to put it there anyway.

Here in zone 7/8 around Seattle, it is often times not only hardy, but completely evergreen, and known for being extremely tough to eradicate once it gets established in an area. In will grow into and through lawns and just about anywhere else here, although I have found it is rather hesistant to spread onto or come up through ground bark. But I don't think that will last forever because the bark will degrade and off the ajuga will go. It forms extremely dense mats once it is established, and spreads quickly, as you noted. I myself love it, but my father cringes at the site of it since he has had to try and rip out so much from his yard, often unsucessfully because you never get all the roots. My stepmom donated four tiny little things to me a couple years ago, one of the driest and hottest summers on record. I could barely keep them alive, and it didn't really grow at all. But now, they are beautiful and thick, and I have plenty to distribute around the yard anywhere I don't mind them taking over. They were just beautiful in bloom about three weeks ago (though I think lovely the rest of the year too):

Aaron

Here is a link that might be useful: {{gwi:1253513}}

I have mixed results with ajuga. I love Burgundy Glow, but after three tries, I gave up on it. My best-performing ajuga is an unknown one I got at a swap. It has burgundy-ish colored leaves, and came back strong this year.

About a mile away from me is a small house where they have a huge swath of ajuga in their lawn. It is absolutely spectacular at the moment!

:)
Dee

I am blessed (?) with ajuga in my lawn. No way to get rid of it. Hopefully it will completely cover my lawn and I won't have to mow.

I planted a bunch of Chocolate Chip Ajuga last season. I had a lot of them die at first, but I think that's due to me not teasing the roots out before I planted them, and underestimating how much water they needed. I have found that these guys really need a decent amount of water. This hill in this photo is east facing, so it mostly gets morning sun. These plants were tiny when I got them, and they have all increased their size by a factor of 4-5 in just one season. My goal is to cover this whole hillside with them, as I wanted something that would suppress weeds. They are producing awesome looking neon blue/purple flowers right now.

WOW this is an old one resurrected. My ajuga still lives and thrives!! It does die back but always regenerates. My beds are full and covered where I plant it. My gardens get watered every week regardless of rain so they stay moist..my zone seems to be with in this plants tolerance because as I say no matter how bare things look about now by mid summer the ajuga fills in and then some. My mother in law died three years ago yesterday. I have many plants from her gardens. What I know for sure is until you try it in your own garden and give it time..you will never know how a plant will do. Every experience is different!!

It seems the fancy ones don't stick around for me, the plain Burgundy rule in the end. They are taking over the turf in the neighbors yard, that used to be my yard years ago, before the neighbor bought the property. My view is don't fight it, that's less turf to care for.

I planted 16 (gallon pots) of Burgundy Glow and 2 years later all were dead. Stick to the ordinary old fashioned ones.