Posted on 01.03.2016 |
Updated on 16.07.2018 |
Added in Kevin's Propagation/Plant Focus Blog/Healing Gardens
The small Tree Peony plants in bud are a result of young plants that were collected from a bark path beneath the large herbaceous shrub of a Paeonia ludlowii during the spring of 2013. The young plants were initially grown on in 1 litre pots for 18 months before being potted on into 2 litre pots in the autumn of 2014.
 Small Tree Peony Plant in Bud |
 Paeonia Root System |
A substantial root system has taken formation while growing the plants on in the cool section of the glasshouse through the last two winters. From my personal experiments I have observed that some hardy plants, herbaceous deciduous/evergreen shrubs produce more vigorous root systems in response to growing on under cool glasshouse conditions between 5 – 8 degrees centigrade. (Reference to my article on the propagation of Pohutukawa, Hardy Plant Journal, autumn 2014.)
The 2 litre pot plants of P. ludlowii will be placed outside in late May to grow on for another season.
Seed Preparation of P. ludlowii
 Paeonia Seeds in Bark |
 Paeonia Seeds in Hand |
Seeds were collected from the barked path early this winter. Time constraints have taken a hold in not enabling me to stratify the seeds within the cold frame. Tree Peony seeds go through a stage of double dormancy. The radicle, the embryonic roots are formed in the first year. The plumule, the shoots, are formed in the second year.
Fluctuating temperatures are required to trigger germination, cold – warm – cold. The plants of P. ludlowii which were potted up in the spring of 2013 had completed that cycle of dormancy.
 Paeonia seeds on Glasshouse bench |
 Soaking Paeonia Seeds |
The seeds that were collected this early winter were placed out on the bench within the cool section of the glasshouse. On the afternoon of Friday 26th February the seeds were placed into a container of water to soak for a period of 18 – 21 hours. The objective was to soften the testa, (seed coat) prior to sowing. Of the 18 seeds that were soaked, 4 seeds were viable, that is they sank, as opposed to floating in the container. This was recorded as a rate of just under 25% seed viability. The period of placing seeds on the glasshouse bench, (cool section) for a few months suggests seed viability was affected.
After a period of 21 hours the seed coats of the viable seeds had become permeable. I was able to insert my thumb nail into the testa, but still needing to apply some pressure in order to break the surface.
My experiment was to rupture two of the four seeds with a pair of secateurs. The seeds were then sown into a very gritty compost mix of 50/50 seed compost, and horticultural potting grit. The remaining two seeds were sown directly into the gritty mix without damaging the seed coat, thus to draw a comparison. I use potting grit as a preference to grit sand as the composition creates a more open structured mix. This can increase quality of germination and successful root development.
 Potting Grit on left, Grit sand on Right |
 Inserting Paeonia Seeds |
The pots of P. ludlowii seeds have been placed outside for the remaining winter exposed to cold night temperatures. Visible germination should occur within a twelve month period.
