Eucalyptus Hardiness

by Andrew Brookes Rainbow Eucalyptus

We have been planting and growing eucalyptus for almost 20 years and have experienced a wide range of growing conditions. This past winter we did suffer a cold snap of around 14 days and we recorded a few nights of - 10C in our nursery in Worcestershire. Most of the hardy eucalyptus we grow can take this temperature with just a little leaf scorching when planted in the ground.

The hardiness of a eucalyptus is a measure of the frost resistance of the root system and not the foliage. This is where potted eucalyptus may struggle over winter. Root death occurs at around -4C.

This can be prevented by moving your potted tree to a sheltered area, undercover and out of the wind where possible - a Greenhouse or sunroom would be ideal. If left outside hardy potted trees  would also benefit from being wrapped in hessian or placing inside a larger pot and stuffed with straw. If you are growing any of the non-hardy eucalyptus such as E.deglupta, E.Citradora, or E.leucoxylon and you don’t live in Cornwall, you will need to over-winter completely frost free and in a well lit area.

If your eucalyptus planted out in the ground has suffered over winter and is looking pretty dead, don’t give up hope!  The lignotuber lies just above or below the surface. If your tree was frozen to the ground, they often send out new growth this time of year. So, it’s worth checking before dismissing.

This year we are growing a few new species, E.crenulata – rarely found out in the wild, and is a good all round variety. This species is an endemic to the Acheron River valley, Victoria, Australia, where it grows in wet valleys so extremely well suited to the UK climate. It’s a small to medium tree which will brighten up a dull corner to any garden. It responds well to pruning, can be pollarded or coppiced making it very useful for hedging or screening. It’s quick growing but doesn’t become a monster. The foliage is a silvery sage green and very aromatic and produces super white flowers for bees. An unusual attribute for this eucalyptus is that it will grow in part shade along with E.neglecta which we are also growing this year.