Allium Fever

Ornamental onions are hot patooties.  From big, bold, purple globes to small pink half-moons, there is no end to ornamental onion-y goodness out there with 30+ species and cultivars in the trade.  There’s no substitute for ornamental onions in regards to architectural drama – the perfect geometric foil to wispy grasses, floral spikes, and umpteen daisy-thingies.  The seed heads from the sturdier species will persist and add interest to autumn and winter perennialscapes (not sure if that’s a word).

Not one but TWO cultivars of Allium on the cover of the fabulous new Chanticleer book…

All are members of the Allium genus, just like those onions sprouting in your kitchen counter veg basket – hence the deer- and small mammal- resistance factor.  However…there are some issues.

  • Can be short-lived.  I have first-hand experience with this – plant, enjoy for a year or two, then…where did they go?
  • Bloom time is rather vaguely defined.  Most catalogs list “early summer” or “late spring” for most cultivars.  But if you want continuous purple orbs, what’s the order of bloom?
  • Can be expensive. Bulbs for some of the mammoth “softball” sizes will set you back $5-$7 each (the bulbs themselves are huge).  This is of particular concern due to the first item.
  • Foliage failure.  For some of the largest species and cultivars, the foliage starts to die back around (or even before) bloom time.  Not a lot of time to put the necessary energy back into that big honkin’ bulb.

We already have a multi-year lily perennialization trial going in conjunction with Cornell and some other institutions.  I thought I might try the same thing with Allium.

Student worker Lauren, after a long day of taking data on a gazillion lilies.
Student worker Lauren, after a long day of taking data on a gazillion lilies.

Unfortunately, I had this bright idea in November – well into the bulb-ordering season.  I tried to compile as complete an inventory as I could, ordering from several vendors.  Ended up with 28 species and cultivars – as much as the space prepared (check out that nice soil!)  could hold, at our urban horticulture center near campus (Virginia Tech is in Blacksburg, USDA Zone 6, about 2000′).  We put five or seven bulbs (depending on size) in each plot, and replicated the whole thing three times.

Ready to plant!
Ready to plant!

We’ll take data over the next three years on time of emergence, bloom time and duration, foliage duration (have a nifty chlorophyll meter that can help quantify that), some growth measurements, and perennial tendencies (or not).  My hope is to end up with a really specific chronology of bloom times plus life expectancy.  Yes, this was just a patented Holly wild hair; luckily I had some general funds to cover it. But I do think our little onion project will be of interest to more than a few folks, whether professional landscape designers or home gardeners.  I know I’m excited to see the results ($30 for five bulbs – yeek)!



10 thoughts on “Allium Fever”

    1. I’ll certainly let our GP community know how things are going! Again, this will be a multi-year study. The specific data will (hopefully) end up in a research publication; once that comes out I’ll do a nice Extension fact sheet. Of course all is dependent on whether or not the resident groundhog digs them up out of curiosity.

    1. Depends on the Allium. some produce a few seeds which are viable. some produce lots of seeds that can be spread too much. and some don’t produce viable seeds – I have never been able to get seeds from Globemaster

  1. Interestingly Allium fever hit me last fall as well! I have always grown several of the California natives at the nursery, even if they are not good sellers, (but if I don’t who will?). But staring at all the amazing ones out there in the trade I decided to see if some of the higher zone tolerant types can be pushed to accept San Francisco Bay Area increasingly warmer climate, at least as a short lived oddity… hopefully they will condescend to last more than a single year! If not perhaps their blooms will coincide with our Allium unifolium and I can play with hybridizing with the most vigorous local species…. And Holly I am glad you have a bit of discretionary general funds to play with!

  2. Hey there Hap! Do it!! It’s a genus ripe with potential for breeders. I just scratched the surface of species alliums in our trials, as seems to be more hybrids that are prevalent in the trade. If I had more space (and dough) I could really go crazy:

    And to answer Sue – it depends. Straight species are more inclined to. The big hybrids, not so much. You can get seed for some of the native alliums at places like Prairie Nursery.

  3. Awesome genus to study, Holly. AA spaerocephalon & (I think) unifolium are the only two unweedsome species I have had success perennializing here in Atlanta’s heavy soil, outside of chives, garlic chives, and leeks. How much more cold do your trial beds get on average than Atlanta?

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