This video talks about how to protect your tree over the colder, winter periods.
In the UK we don’t have very harsh winters but the temperatures can drop to -5/10 degrees and we like to protect some of our Bonsai trees. Some of the larger Bonsai are hardy like the Scots Pine and some of the Maples are hardy but to be safe we protect some of the trees.
As a rule the larger the tree and pot the more they are able to withstand the cold because the larger pots don’t freeze as solid as some of the smaller pots.
However, trees which have been newly imported need to be protected as they haven’t had time to acclimatise to the UK weather.
With the trees that need protection some go into shade tunnels. All our Azaleas are under the shade tunnels - although hardy, the shade netting protects them from severe frost. If you are unsure what to do with your Bonsai, they can be placed in an unheated greenhouse (needs to be unheated otherwise it can confuse the tree and it will break its dormancy and think it's spring)
The Junipers also go under the shade tunnel. Once the first frost touches the tree they get ‘frost blush’ which means that the foliage looks burnt on the outside, however on the inside of the tree the foliage is green, the orange/brown colouring doesn’t mean the tree is dying. Come spring they will turn green again. Placing bonsai underneath benches is also a good way of protecting them - you can cover with a sheet of plastic which acts against cold winds, but remember on sunny days to let the wind blow around the tree to avoid fungal infections.
In the poly tunnels we protect our Trident Maple which aren't as hardy as the Japanese Maple. The Pyracantha and the Korean Hornbeams are also protected under the poly tunnel.
We always ventilate the tunnels. If you completely close them off you may get fungal disease so fresh air is important.
Top Tip: incurve pots are particularly vulnerable to frosts when the soil freezes there is nowhere to go and it can burst sidewaays which can crack the pot.
Frost can make the tips brown on yews and the cypress but don’t worry as they will come back to their green colour in the spring.
In our unheated greenhouse when the temperatures are below freezing we cover our trees with horticultural fleece (if you don't have this you could use an old net curtain) which is enough to protect them in freezing temperatures.
Top Tip: if you have a smaller pot and don’t have an unheated greenhouse to protect them you can cover the pot with bubble wrap to prevent the root ball from freezing.
Take care of your trees in Winter and they should come out again in the Spring.
Please visit www.herons.co.uk for our Bonsai trees, tools and accessories.
The nursery can be visited at:-
Herons Bonsai
Wiremill Lane
Newchapel
Nr. Lingfield
Surrey
RH7 6HJ