Wednesday, March 12, 2014

My favorite plant of the week: Ageratum corymbosum

I'm tempted to call my favorite plant of the week the plant of many names.  Frankly, even after doing some on-line research, I'm still not sure what its proper botanical name is.  I purchased the plant in January 2011 from Annie's Annuals & Perennials as Ageratum corymbosum.  Annie's site later showed a name change to Eupatorium sordidum but is now again selling it under the name of Ageratum corymbosum, without an explanation for the change.  I've found pictures of the plant on-line under both names, some supplied by Annie's and some by other parties.  I also found cross references to Bartlettina sordida, which has remarkably similar flowers but less purple foliage. However, Annie's sells that plant as a separate offering.  As my plant looks like an Ageratum and as my original supplier is currently using that name for it, I've used that in the post's title but, in the interest of fair disclosure, you should be aware of the confusion regarding its classification, especially as descriptions of the plant's size and hardiness vary with the classification used by the different sources.




Annie's site projects the plant's mature size as 3 feet tall and wide.  Width is hard to assess as I have multiple plants that have grown together but mine is currently closer to 4 feet tall.  It's evergreen - or, as Annie's describes it, "ever-purple."  The leaves have a velvety quality and take on a purplish coloration as they mature.  I prune mine ever so slightly after its main spring bloom, just to clean it up.




It produces some blooms off and on during the course of the year but, in my garden, the heaviest bloom occurs in early spring.   Buds began appearing in January but the blooms take their time.  It's coming into full bloom now.  The flowers have the classic flossy appearance of the annual Ageratum.





It's generally described as a shade plant.  Mine receives morning sun but it's in shade during the warmest part of the day.  The University of Arizona says it can tolerate some drought but requires water during the summer dry season - mine does fine on a drip irrigation system.  Annie's site says it's root hardy to 15F.  Dave's Garden projects a similar level of hardiness for Ageratum corymbosum but suggests that significantly higher minimum temperatures are required for Bartlettina sordida.  As we haven't seen a freeze in the time we've had the plant, I can't offer assurances one way or another with respect to winter hardiness.

Ageratum corymbosum - or whatever you wish to call it - is my favorite plant this week.  Please visit the host of this weekly favorite plants meme, Loree at danger garden, for her pick this week and to find links to other gardeners' selections.


12 comments:

  1. That is a beauty, and from a distance to me it looks like an Epimedium!

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    1. I wish I could grow Epimedium here! In a fit of zonal denial, I tried one once but it didn't fare well.

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  2. Wow, that is a beautiful plant, the leaves are so pretty and so are the flowers. I have to admit I was amused by the long caveat that you opened your post with. Those darn botanists are such a pain in the ass, aren't they?

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    1. Yes, indeed they are! It's one thing to change the classification once but changing it back (without acknowledging the change, much less explaining it) was really irritating!

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  3. Oh you know I love dark foliage, although of course I do prefer it can live through a freeze. Is there any fragrance to the flowers?

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    1. There is a light, sweet fragrance - something I didn't know until I stuck my nose into the flower in response to your question!

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  4. I hate when there's confusion about plant names. Google images only makes it more confusing sometimes when I'm trying to ID plants. Whatever its name is, it's beautiful!

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    1. This is the most case of classification confusion I've come across yet, Amy.

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  5. I like the description 'ever purple' - extremely odd that different growers have different names. Confused.....you soon will be! We've an insurance company advertising over here called confused.com - perhaps they should consider using this plant for their PR.

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  6. I have just received the same plant from the same seller and couldn't remember 'growing conditions.' Right now it is so small and tender, but I can't wait to get out into the garden this afternoon and find it the right home.

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  7. The pictures here especially the leaves definitely look more like the Bartlettina sordida. We have both this one and the Ageratum in NZ. The Ageratum leaf here in NZ is much smaller than your photos and looks like the Bartletina leaves grown here, which by the way unfortunately is classed as a weed now :-( Thankfully not the Ageratum. Some nurseries can get the names wrong! If you can find a botanist he/she might be able to tell you exactly what its name is.

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    1. The same seller also offers Bartlettina sordida so my guess is that they've made a valid distinction between the two. However, they originally offered it as Eupatorium ;)

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