The taxonomy of this group of lilacs native to China Korea and Japan has been confused and evolving for many years.
The plant marketed as `Dwarf Korean' lilac, for example, is Syringa pubescens ssp. meyeri `Palibin,’ at right. It blooms just prior to the common/French lilacs.
Meanwhile, `Miss Kim' (Syringa pubescens ssp. patula `Miss Kim’), a second very popular "dwarf" lilac was grown from seed collected near Seoul, South Korea in 1947 and released by the University of New Hampshire in 1954. It tends to flower with or just after the mid-season French hybrid lilacs and features shiny, slightly elongated leaves that look quite different than most lilacs, at left.
And, though not readily available, the littleleaf lilac cultivar `Superba' (Syringa pubescens ssp. microphylla `Superba’) can make for a good shrub border plant.
All three of these plants are very good lilacs - as lilacs go.
Their flowers, which tend to be smaller and more compact than the French hybrid lilacs, are icy blue with maybe just a touch of pink. And the leaves of all three plants will occasionally show hints of red in the fall as compared to the yellow-green of other lilacs.
Understand, however, that none of the three are "dwarf" in size!
I've personally seen `Dwarf Korean' lilacs in the immediate Syracuse area that are at least seven to eight feet tall and wide. And, each of the three `Miss Kim' lilacs clustered together in this picture, at right, that I took within the Zucker Shrub Sampler garden at Cornell Plantations in Ithaca are about seven feet tall and wide.
The mature size of these plants can also pose problems when grafted onto four to six foot tall "standards" and grown as "trees."
For example, in the picture at left, three grafted Korean lilacs (two `Miss Kim,' center and left, and a `Dwarf Korean,' at right) are planted about four feet apart in front of the entrance to Syracuse Stage in Syracuse. Below, at right, is a picture of a ten year-old `Dwarf Korean' lilac that's about a mile from Syracuse Stage. It's the better part of eight feet tall and every bit of ten feet in diameter! Given the potential size of these plants, how do you think the three grafted lilacs in front of Syracuse Stage are going to fit together as they mature?
Meanwhile, Bailey Nurseries of St. Paul, MN continues to release additions to its "Fairytale" series of "dwarf" lilacs. Resulting from crosses between the `Dwarf Korean' and littleleaf lilacs described above, this group includes the increasingly common `Tinkerbelle’ (dark pink), as well as `Fairy Dust’ (pale pink), `Sugar Plum Fairy’ (light lavender), and `Prince Charming’ (lavender-pink).
As with the `Dwarf Korean', `Miss Kim,' and littleleaf lilacs above, these plants can all reach at least six to eight feet in height and width - regardless of what garden center labels may say! There are also reports that the “Fairytale” lilacs may be susceptible to a “sudden death” when grown in evenly slightly damp soils and observations that this group of lilacs may not be as winter-hardy as other lilacs.