By late summer or fall, most of the peonies have already stored as much energy as they can for the year and go dormant. This means that their leaves will change colors, fall off, and the tuberous roots will likely shed their feeder roots as they go to sleep. Another way to tell is when the buds for next year really start swelling up in preparation to sprout by next spring. Tree and itoh peonies should have completely woody stems by this point.
Here are some of the seedlings
Most of them will produce more than 1 bud as a 1st year seedling, even if they are weaker ones which only have 1 leaf.
Here's a 1 budder,
Some species will have greenish buds. It's pretty hard to determine how their flowers will look like, but I can at least tell that I have many different species by the starting leaf shapes, growth habits, and colors.
Here's a stronger 1st year tree peony seedling which has multiple leaves and major swelling in the size of the trunk, perhaps getting up to around 1cm in diameter due to the stored energy for the last 6 months. They are typically close to done with the storage of energy at this point since the leaves seem to be losing their color, and overall vigor.
Some species are still actively growing, but these happened to have already shed their first leaves, and produced a second pair of leaves. I have no idea if this will compromise the size of next year's growth, but one of them is still producing a new leaf in September which seems a bit too late.
Here's a 2nd year seedling which hasn't seen much trunk growth yet, but it will happen in the next 2 months as the energy gained throughout the growing season gets stored for next year's growth.
This is the larger kinshi Japanese tree peony that flowered this spring which is really starting to shrivel up its leaves as the nutrients travel into the wood. This was from a graft which appears to clearly be on its own root system by now after 3 seasons in the ground.
Here's a kamata fuji Japanese tree peony which lost its herbaceous nurse root in the spring, but still had enough energy in it to manage to get established and grow its own roots. This is an indication that it is possible to take branch cuttings as long as the buds are not flower bearing buds. It is showing signs of dormancy.
Here's my bartzella itoh peony which is one of the few which were never divided up, and it is making lots of buds, many underground ones, which is an indication of a strong output for next spring. Itoh peonies are supposed to be split up every 4-5 years to maintain their health, perhaps longer if you start with smaller divisions. I decided to keep this one in one piece because I really wanted to see its flowers by next year.
23 September 2012
Here are a few more pictures as it seems like tree peonies continue to develop into the fall as the stems tend to get thicker, and buds grow fatter. One pattern I've noticed is that the seedlings growing in pots tend to continue growing while the ones in the garden beds are more likely to go dormant.