You can apply the same technique for growing the Asian counterpart of our Jeffersonia, Jeffersonia dubia. 

I’ve repotted some fine young Jeffersonia seedlings two weeks ago and now it took me a great pleasure to write this post (year 2016 :). Jeffersonia diphylla (Twinleaf) is a wonderful NA species that should be mandatory for all gardens; the pictures show it in its glory at Aspen Grove Gardens.

A delight from early spring (April) to fall, and notice that although it is a woodland species, it can be grown with a fair amount of sun. At least sun in the spring when it flowers it is best.

Just like other bulbous/tuberous species that form rhizomes, Jeffersonia species need 2-3+ years to develop their root system before they will start flowering. The faster & better their rhizome grows, the sooner they will flower. Again, it is very easy to underestimate the size of a seedling root system. This is why the repotting is very important and can be done either in the fall or spring. Each period has its pros and cons, also depending on your winter storage possibilities.

 I will outline the whole process from sowing to repotting the seedlings:

• Sow the seeds as soon as possible after collecting/receiving them. Otherwise, they have to be keep in moist storage at room temperature during the summer, and then in cold/moist storage. One observation is that these seeds don’t keep too well in moist storage, and they are usually available (if) for a short period.
  
• Sow as usual in individual pots or use my ‘space saving method’ – also very practical for someone who doesn’t want to have one pot sitting around by itself. Sow all the seeds in one larger pot and ‘plant’ the pot in the ground (in late fall I added some mulch on top, removed in early spring).

Tip: ‘plant’ the pot close to a shrub/tall perennial plant that will shelter and shade the seedlings; also close to the house so you won’t forget about it (the seedlings require extra watering during dry spells). Mine was close/beneath an old Peony, unfortunately I don’t have a picture.

• The seeds are germinating somewhere in May, depending on the locality and have very good germination capacity. Foliage wise, not much will happen the first season besides the one shoot with the cotyledon leaves. But keep in mind that underground the root system keeps growing!

• Use a diluted fertilizer once in a while (only if you remember…), water regularly; nothing else to do till late fall.
  
• By late October- early November watch for signs of dormancy and let the pot dry out a bit.
• If you want to transplant them in late fall, tip off the whole content and gently separate the seedlings (don’t forget to congratulate yourself, take pictures, eat some chocolate/cake…)

• Repot them in a fresh potting mix (I don’t have any ‘special’ formulas); one or more seedlings/pot. Planting 2-3 seedlings/larger pot will make a ‘clump’ faster.
  

• Water well, and if it’s late November, that’s all they need.
• Winter storage for the pots: in a cold frame, or again, ‘plant’ the pot(s) in the ground and throw mulch/few leaves on top.

• Another good option is to transplant the seedlings in the spring or grow them one more year in the same pot; this way the seedlings will be larger in size and easier to handle, especially for those who are not used with transplanting little seedlings.

Waiting for the first flowers in 3-4 years! Until then, both species have a very nice foliage, colorful in early spring, then with interesting leaves.

Special thanks to Robert Pavlis @ Aspen Grove Gardens, for growing this beautiful, ‘photogenic’ species and providing the material for this post, i.e. the Jeffersonia seeds :)

Update: More on Jeffersonia germination