Keep in mind when planting that Crescendo Blue is thought of as hardy, so Crescendo Blue will tend to go dormant or grow slowly over the winter months. Crescendo Blue requires a sandy, loamy and clay soil with a ph of 5.6 - 6.0 - it grows best in weakly acidic soil.
By our calculations, you should look at sowing Crescendo Blue about 105 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Crescendo Blue is a hardy plant.