Hi. Do hydrangeas seed? and is this a viable way of getting many plants?
The short answer is that some Hydrangeas produce viable (non-sterile) seeds, and others do not. It is more effective to propagate these shrubs by cuttings, or by layering.
There are several different types of Hydrangea, and although you don’t say which type you are interested in, I am making the assumption that you may be thinking of Hydrangea Arborescens ‘Annabelle’, with its showy white flowers, which is very popular in Toronto and can be found everywhere throughout the city. Its flowers are sterile, which means that they do not produce seeds.
Other types of Hydrangeas are:
- Hydrangea macrophylla(Bigleaf Hydrangea) – Large colourful mophead or lacecap flowers. This is the group whose flowers are blue (under acidic conditions) or pink (under alkaline conditions). It is possible to propagate these Lacecap Hydrangeas from seed. They produce inflorescences that are composed of a mixture of large blossoms which surround smaller inconspicuous flowers. It is the smaller flowers that produce the seeds that are viable for planting.
- Hydrangea quercifolia(Oakleaf Hydrangea) – Can be easily recognized by the leathery oak-like leaves. Flowers are cone-shaped.
- Hydrangea paniculata(Peegee Hydrangea) – ‘Limelight’ is one of the varieties in this group. These types of hydrangeas can be identified by their cone-shaped flowers.
Any of these types of Hydrangea can be successfully rooted by cuttings or by layering. Here is a website that describes both techniques with plenty of illustrations: https://plantaddicts.com/propagating-hydrangeas/
If the Hydrangea you have is a Macrophylla, and you’d like to try your hand at propagating by seed, this website provides step-by-step instructions: https://homeguides.sfgate.com/seed-hydrangea-64353.html It is important to note, though, that plants grown from the seeds of hybrid varieties may not display the same characteristics as the parent plant.
All in all, cuttings or layering are the propagation options that have a better chance of success.