You need to take them before winter, say October. Up to 12" lengths of pencil-thickness pieces. Avoid flowering pieces or trim those off. Then either make a slit in the soil about 8" deep and put some sharp sand in the bottom, put in sticks, close up slit with soil firmly and ignore until late spring, when you should have fresh growth OR put around the edge of a big pot, again well-drained, and put in a sheltered position (same is true for the ground-planted pieces, actually) and ignore - north aspect is OK. I have some in a pot right now from last autumn ;)
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