If you want to propagate them vegetatively, the roots can be divided. You should Google "eremurus propagation". There is a lot of information on the web. However, I recommend growing from seed. It takes a little longer, but you can get huge numbers of plants this way. Sow the seed in a gritty mix, water, keep warm for 2 or 3 weeks, then chill at 40F (5C) for 3-4 months. When the seedlings come up, give them strong light, but keep the soil cool. Give them lots of bone meal and NPK fertilizer. When they start turning brown, let the soil dry out. If you have been living a good, clean life, you will have flowers in three years. If you have been bad, the roots will all rot (probably because the soil was too wet during the dormant period). It is very similar to growing tulips or frits. Where do you get the seed? From the plants you just bought when they bloom next Spring. They will make hundreds of seeds. Or you can buy seeds from Jelitto and others. It is getting pretty late to start them this winter.
