Plant Doctor Archive

Propagating tree paeonies

I'VE got a lovely pink tree paeony that now has a big seed pod. How and when can I sow the seeds and will the plants have the same type of flowers?

UNLESS your tree paeony is a true species that has self-pollinated, any seedlings you grow are unlikely to be exactly the same as the parent. But you may still end up with some interesting plants and it would be fun trying.

Leave the pod on the plant for the seed to fully ripen, checking its progress regularly over the next few weeks. When it looks as if the pod is splitting open, or if it changes colour, cut it off and take indoors. You could then open it by hand or place in a warm dry place to open naturally.

Ripe tree peony seed is usually about pea-size with a hard dark-coloured seed coat. Successfully germinating them can be tricky as they can have a rather complicated inbuilt dormancy factor that needs to be overcome. I recommend you try three different techniques.

First the simple approach. Take a few seeds and sow them in a pot of seed raising mix and place it outside in a sheltered shady spot where the seeds will be subjected to the normal high and low temperatures of autumn and winter. Make sure the mix stays moist.

Secondly, use a craft knife to knick a small hole in the hard seed coat of some of the remaining seeds. Be careful not to cut your fingers! Then sow them and treat in the same way as the first ones.

With the rest, nick the seed coat and soak them in water overnight. Then mix them with some moist sand in a sealed plastic container, and put in the fridge for 4-6 weeks. Then sow as before and place in a warm, sheltered spot such as a window sill, making sure the mix doesn't dry out.

Be patient, they could take many weeks to germinate. When the seedlings are large enough pot them up into individual pots for planting in the garden later. Seedlings take quite a few years to mature so you'll have to wait patiently to see what colour the flowers turn out to be. Good luck - let us know how you get on.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.