Allium atropurpureum

Mark McDonough
Thu, 24 Jun 2010 20:37:28 PDT
Stephen Putman <> wrote:

>Hi Mark, 
>Thanks for your reply, I really wanted to know more about this. I don't 
>have photos of my A. atropurpureum, but it does look exactly like your 
>photos.  There were no seed head bulbils, rather there were bulblets 
>surrounding the "mother" bulbs.  I've no idea how long it takes from 
>seed, but I was concerned when I saw all those bulblets around the base 
>of the original bulb.  The seed head seems to be likely to contain just 
>seed, not bulbils.  Are bulbils and bulblets "technical" terms, or just 
>words we've made up for our convenience and to confuse each other? 
>Steve in still scorching Delaware, where the storm fronts roll through 
>with impressive lightning and thunder and power outages, but no change 
>in the weather. 

Hi Steve, there is indeed a difference between "bulbils" and "bulblets"; bulbils refer to the small bulb-like propagules that can appear in the flower heads on some allium... often these will actually sprout green leaves while still attached to the flower head (such as the recently popular yet silly plant Allium 'Hair').  Some plants, as in a number of Araceae like Arisarum species, can produce bulbils in in axils of leaf petioles.  But, just think of these as aerial bulb babies.  On the other hand, bulblets refers to young bulb babies, typically underground, but some species of Allium like A. rotundum, and even A. caeruleum and caesium, can produce lots of these tiny bulblets just under the bulbcoat of the mother bulb, sometimes a little ways up on the stem.

So, I'm surprised to hear of the existence of bulblets on A. atropurpureum, it is not that I don't believe you, it is just that I have never encountered such a form.  For years I grew Allium caeruleum, the typical form available from Dutch bulb sources, and the plant dies out after a couple years, and have noted that form typically has some "bulbils"  in the flower head, yet I have not noticed any proliferation of bulblets that I can remember.  Then, I received an awesome form of Allium caeruleum from Denver Bot Garden, and this form does not have any bulbils in the flower head, but does make a LOT of bulblets at the base of the bulb and basal stems... I was happy about this, as I'm still finding this species tricky to find a spot that it likes and will act reliably perennial in... so I harvested the bulblets and planted them elsewhere.  This year the DBG form is in decline, just 2 flowering stems from about 10 last year.

I would keep an eye on a plant that shows lots of bulbils particularly as these are most prone to invasiveness (A. canadense, vineale, carinatum, and to a lesser extent oleraceum), and also watch those that make lots of bulblets.  So far as the latter, I have since lost my plants of Allium rotundum (it makes lots of bulblets, but the species is not invasive), I have a tiny bit of blue-flowered A. caesium left, and in decline with A. caeruleum... so bulblets in themselves do not necessarily predict great invasiveness.  

here are some photo links... 1) Allium caeruleum good form at Denver Botanic gardens... 2) basal bulblets on A. caeruleum DBG form, and... 3) a flower head this spring on Allium caeruleum DBG form.………


Mark McDonough
Massachusetts, USA, near the New Hampshire border, USDA Zone 5

sweltering in MA today, but rip-roaring thunderstorms came through and torrential rains... 20 minutes later sun came out and drier air and cooler temps... yay!.

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