By far the easiest way to propagate yourself some new silver birch (betula pendula) is by collecting seed. You could also take cuttings but honestly seed is quicker and easier.
All you need is some good quality potting mix, a container and some pots.
When to collect silver birch seed?
Silver birch seed generally ripens anywhere from mid/ late summer into autumn. The earlier you’re able to collect the seed the better.
The seed turns brown when ready to sow. When you pick it, it will very easily break apart in your fingers. This is how it’s dispersed naturally by the wind.
Occasionally you’ll find small seedlings sprouting under existing birch trees. These could be collected whenever you notice them. This most often occurs in spring (last years seed) and autumn (this years seed).
It’s best to pluck these out of the garden as soon as you notice them and pot them into individual pots. If left alone in the garden 99% of them won’t survive.
How do you sow silver birch seed?
We like to sow the silver birch seed into a styrofoam vegetable crate filled with good quality potting mix. The container isn’t important though, whatever you have available that will provide adequate drainage. The potting mix needs to be kept moist but not saturated!
We sprinkle the seeds over the surface of the potting mix. You can lightly cover the seeds with more potting mix or simply leave them on the surface. Water them well and place the container in a nice sheltered area. We use our green house but anywhere protected from weather extremes is fine.
How long till the seed germinates?
The seeds will germinate incredibly quickly within 2 weeks you’ll notice tiny little birches emerging from the potting mix. By around 8 weeks the little birch seedlings should be ready for potting.
If they aren’t don’t worry. Obviously in some areas winter comes quicker than it does for us. If necessary you can keep the seedlings in the container you sowed them in for the entire winter. Then pot them up the following spring.
We are lucky in that we can pick our silver birch seed in summer and pot them up in autumn.
Potting silver birch seedlings
We pot our silver birch seedlings into small 50mm (2”) pots. If you can buy them in your area the small, deep forestry tubes are best. We like small pots like this cause they easily fit into seedling trays and take up very little room.
You can of course pot into any old plant pots you have lying around. What’s important is you use a good quality potting mix to plant the silver birch into. Any general plant potting mix will suffice.
To pot slightly fill the pot with potting mix, place the plant into the middle of the pot and backfill around the seedling. Keep the soil moist at all times, but again don’t overdo it! Moist is not waterlogged!
We then leave the seedlings in these small pots for the entire winter (why we like small pots). Over winter the roots will continue developing even though nothings happening up top.
As soon as spring rolls around we pot them up into larger 200mm (8”) pots. For those of you who still have them in the sowing container now is the time to plant them into pots. Don’t feel as though you need to go into small pots first.
We only keep them in the small pots to save on room in the nursery over winter. You can pot them directly into a 200-250mm (8-10”) pot if available. Remember to use a good quality potting mix.
We also like to add a small handful of slow release fertiliser. Young silver birch will grow incredibly fast if given proper nutrition.
By the end of spring- early summer you should now have a little mini forest of silver birch about 1 metre (3’3”) tall. The roots should be strong and healthy and ready for planting into the garden, along a driveway, given as gifts or sold.
Thanks for reading 🙂 Happy planting!