There is only one drawback to this plant (Salvia sclarea turkestanica): it is biennial. It germinates and grows one year and, the second year, it reaches maturity, blooms and dies. I grew it for the first time last year and it turns out to be a stunning plant.
It is not attacked by any diseases or insects. In fact it attracts many pollinators. It is easy to grow and requires no special treatment. It is big, but it does not need staking. In spring its large leaves are attractive, and later on it gets completely covered with flowers for at least two months.
|Biennial Clary (Salvia sclarea turkestanica)|
Even before it starts flowering, the foliage is particularly attractive
When the flowers eventually come out in late spring, (technically they are bracts rather than actual flowers) they are almost white. In fact there is a cultivar of this plant called 'Vatican White' whose flowers stay white.
As the summer progresses, the bracts expand, and the flower spikes get larger and larger, and the colour turns to a light lavender.
Eventually there is a touch of blue added, and the colours intensify to produce the lavender cloud effect.
It is easy to grow from seed. However, if you want to always have it, you need to start seeds every year (each year, plant seeded the previous year will bloom). This is no doubt the reason the plant is not more common.
It looks like it is going to continue blooming for quite a while, and there has been flowers out since early June. I certainly intend to collect seeds later in the year and plant them next spring. The plants I have blooming this year (there is about five plants in the clump) came from seeds I got in a seed exchange.
For those who are not yet convinced of its value - the plant is reputed to slow down the human aging process (unfortunately, how it does that does not seem to be mentioned anywhere).