Rotary Botanical Gardens - Hort Blog: Perovskia

The drizzle of the last two days disappeared with some sun and blue sky occasionally making an appearance. The temperatures are cooling a bit and this will be perfect for "drying out" the Holiday Light Show (HLS) for the next batch of open evenings (December 17 - December 23, 4 pm - 8 pm). Consider getting pre-purchased tickets and for more information on this event, see www.rotarybotanicalgardens.org. Larry H. was in today to do some work out in the HLS and to check over our paths. Bob K. came in for some electrical finesse work which should avert some potential problems in case of bad weather. We also saw Fern, Maury, Urban, Terry and a couple of others. It was a good "desk day" for me for sure with lots on my radar for 2016.

I've long admired Russian sage (Perovskia atriplicifolia) for it's durability with tough soils, full sun, prolonged neglect and general toughness (hardy to zone 3). The long period of bloom (3+ months) is quite extraordinary as well. Above is a specimen in late summer at Boerner Botanical Gardens (Hales Corners, WI) with the "straight species" averaging about 5' in height. Native to the steppes and hills of Southwest and Central Asia, this plant was the Perennial Plant of the Year in 1995 as selected by the Perennial Plant Association. It's important to note that Russian sage isn't a herbaceous perennial that dies to the ground each year with only new growth regenerating beneath the soil (which can still happen). This plant is a "subshrub" that will typically still have viable buds above the soil and beneath the snow. You will see foliation typically in the bottom 6" of the plant. Stems that touch the ground will root readily so be wary. We cut all of our specimens to 6" in late October to prepare for new growth the following spring (this plant only flowers on new growth). The bluish flowers in mid-summer until fall are accented on silvery stems and while the plant is roughly mounded, it can be a wispy, informal shape as well with full sun being ideal. Some newer selections promote a more upright, or "vase-shaped" habit.

With Perovskia atriplicifolia topping out at 5' or so, it has been perfect for the back of the full sun perennial border, in mass plantings, parking lot islands and corporate landscapes. However, the need for a more compact form in the 3'-4' range has guided breeding efforts with many new varieties coming out over the last couple of years. Bringing this plant in to the "mid border" is a worthwhile goal in my mind. Some consideration has been given to the texture of the foliage with more finely dissected foliage selections although I rarely will note this as significantly different from other selections. Height continues to be the primary consideration with the quest for a true, 24" tall form....