Posted: 15/07/2016 at 19:59
since nobody else has replied, I grow several agastaches....prob a dozen different varieties. Love them all. From orange to yellow to red to pink to blue and all flower like mad all summer. All have different foliage smells from liquorice to mint to chocolate and more.
a couple of things......firstly I would pot on both Black Adder and Blue Boa and do so a few times to produce plants for NEXT year. Yoy can still enjoy them as pot plants this year but they will not like being dug up for winter protection (if you are in a cold area you are likely to lose them in a typical winter)
Secondly, cuttings. I find Blue Boa easy from cuttings right now. Taken from the base or up the stem. I use rooting powder.......it really does make a difference for agastaches. Take the cuttings, trim them up and drop into a saucer of water for 10 mins or so. use a 50/50 perlite and multi purpose compost and water before inserting the cuttings. I use an ordinary unheated propagator in a sheltered warm part of the garden.
Black Adder I find is slightly stubborn. I take basal stems pushing down into the compost to try and secure some rooted pieces and pot these up. semi ripe cuttings also take but percentage success rate is low.
Hope this helps