Is it possible to divide
It is, but it's even easier to take cuttings from your prize delphiniums. For division, dig up the whole plant before spring takes hold. Divide the crown of the plant into a few pieces making sure each bit has both roots and shoots.
Get rid of any old or diseased roots and then replant. Take cuttings in spring when the shoots have started and you will need at least 8cm in length for each cutting.
My Nana used to put them in jam jars for a couple of weeks and they rooted well enough, but you can also insert them into pots of moist sand. Once rooted, pot them up and they will be ready to transplant out within four or five weeks.
When is the best time to take dahlia cuttings?
Early spring, as the new shoots emerge is the perfect time to take cuttings. To speed up the process, dip the base of each cutting into hormone rooting powder. Insert into free-draining compost mixed with silica sand.
The main priority is to get the cuttings to root before they rot, so a free-draining mix is essential. To further speed things up, a little bottom heat is an advantage, so a mini propagator is a fantastic buy.
The beautiful Dahlia 'Thomas Edison' or Dahlia 'Pride of Berlin' are worth looking out for, if you would like to add them to your collection for your late summer border.