I know that repotting can be a bit daunting but there really is no need to fear! Generally speaking the best time to repot temperate species (which includes all sarracenia) is at the tail end of winter/ beginning of spring. This way the plant is still dormant, easier to work with and you aren't disrupting its growing season.
I have this overgrown Sarracenia purpurea that I have been wanting to divide for a while now so I though this would make a good subject to show beginners how to divide a clumpy pitcher plant. All Sarracenia grow from rhizomes that sit right at soil level. All new leaves will emerge from the rhizome as well as all roots. This makes dividing them fairly straight forward.
First gather your supplies. Take a good look at your plant and try to figure out what sizes of pots you need and how many. I also like to have a good pair of small, sharp, pointy scissors to help remove old leaves and split rhizomes apart.
Excellent! Now it is time to prepare your media. Media is the term I use for the dirt/soil that you will use for your plant. I use a blend that contains Canadian peat moss, perlite and a few other things for flytraps, sarracenia, and many droseras. We sell this blend on our site (labeled as the "General Blend") or you can make your own. Just make sure you are choosing componants that are free from fertilizers, minerals, wetting agents, pH balancers, ect. Read the label. Get a bowl or basin to place your media in and add water (remember always use rain, distilled, or RO water). You want it to be moist but not sopping wet.
The first photo is media that is too wet. It drips and can compact when you try to fill a pot. The second photo is media that is too dry. It is still fluffy and light in color. If your media is dry, it can wick moisture away from your plant.
Now the fun begins! Unpot your plant and gently remove the old dirt. You can set up some water and soak the root ball or pour some water over the roots to help loosen it up and encourage the soil to fall away without damaging your roots.
Inspect your plant. Remove all leaves and really start to look at the rhizome. You will begin to get an idea of where to separate. I like to wiggle my thumb in between the rhizomes and start to pull them apart. Take you time with this and work slowly.
You may need those small scissors to cut apart the small runners that attach the rhizomes together. Do not cut through growth points.
After all the dividing this is what I ended up with from that one 4" pot.
Now it is time to pot up all you new plants. You don't want your roots to dry out before you can get them potted up again so you can either pot as you go or place the plants in a tray with a little water, just enough to keep the roots moist. I add my media to the pot and use either my finger or a dibble to create a hole. Your root ball will determine how large and deep your hole needs to be. I try to not pack the dirt in too much. It is good to have the media a little loose so that the roots do not have to struggle and push through compacted dirt. You also don't want it so loose that after you water a few times, you are left with a pot that is missing a few inches of media.
Make sure to leave the upper part of the rhizome uncovered. This is where all new growth will come from and you don't want to pack dirt on this area. This carries true for potting flytraps too.
When you are all done, make sure to water in your plants. If you forget this step, all your work will be in vain. I like to make sure they have extra water for the next week or so and I keep an extra eye on them to make sure they are adjusting well.