'Mongo' aka 'Nanho Blue' aka
'Petitite Indigo' Butterfly Bush
"Look, a butterfly! Did you make a wish?"
-Louise Gluck
b.1943
b.1943
Buddleia davidii nanhoensis 'Nanho Blue' is a semi-dwarf central Chinese subspecies of the common Butterfly Bush. There are three cultivars of the smaller subspecies presently in the nursery trade, but the combination of registered names, trademarked names, & alternative nursery names, makes it look like there are several more. I believe they actually break down into these three varieties by many names:
1) Nanho Alba = Monite = White Dwarf = Petite Snow(TM)Plus further mix & match variants of those often used names. The trademark names in particular cannot be used on sales items without the explicit permission of the trademark owner, so occasionally one sees in a single catalog two separate listings, because the same cultivar was obtained from two separate wholesalers, only one of which had the right to permit the "Petite" label.
2) Nanho Purple = Monum = Purple Dwarf = Petite Plum(TM)
3) Nanho Blue = Mongo = Blue Dwarf = Petite Indigo(TM)
Like the White & the Purple, 'Nanho Blue' is more compactly leafed than most Butterfly Bush varieties. It is easily maintained at four to six feet in height, & five feet wide, if it is hard-pruned annually. The time to prune is late winter, but some earlier incidental pruning will inevitably be done when deadheading or taking blooms for bouquets.
If it is not pruned, but let to go a somewhat wild, it will become rangy, but still very interesting in appearance, with a potential sweep of six or eight feet high & wide, perhaps larger in temperate zones. This compares to the usual six to eight foot minimum sweep of most Buddleia cultivars, which can be considerably larger. In colder zones they behave more like die-back perennials, but on Puget Sound they become large woody shrubs if let go.
To bloom best it needs full sun, & does not require much watering once it is established. We obtained it for a sun-garden by the road & rarely watered it at all, though at high summer leaves will become crisp & drop if it doesn't get a bit of supplementary watering. Also the blooms will dry to grey-brown, clinging still to the branches with some slight lingering decorative value, toward the end of July, but also new deep blue blooms will continue into August if it has been getting supplementary watering. With deadheading it can be induced to rebloom until first frost, but if not deadheaded it is usually finished flowering early in August.
Its sweet scent of wild honey is just about the finest of its many fine attributes. Back when we first brought it home in a pot, I delayed putting it in the roadside sun-garden, as I was trying to figure out how I could get it right by one of the doors where we could smell it all summer long. Unfortunately the stuff closest to the doors gets far too regular waterings for a butterfly bush ever to have been happy, as they suffer from much wetness. So it did end up in the sun-garden it was initially intended for.