Cut off all but five of the spring shoots when they are about 7-10cm (3-4in) tall, making sure you cut down to the rootstock. If you cut above this, many of the lupin and delphinium shoots in particular will be hollow and can't be used.
Removing these shoots may feel greedy, but the plant will actually fare better with only four or five flower spikes, so you are doing yourself a double favour.
Push the cuttings into trays of multi-purpose compost mixed with grit or perlite for added drainage.
Keep them moist and aphid-free, and they should root in four to six weeksReuse content