Hi Sibe,

I have a leggy Eucalyptus tree and don't know how to make it thicken up? Do I prune the top off to encourage growth from the base? Please help before it snaps!!

Kathyio

Our Gardening Expert replies:

Hi Kathyio,

Eucalyptus trees do tend to grow in this way. They have what's called strong apical dominance, which means that the leading shoot dominates most of the plant's growth, so even if you did prune the top off, a single side shoot would soon take over and extend the growth upwards again.

Your plant isn't really very likely to snap. Unless it is growing in a position where it gets little natural light - which is not a good idea - sooner or later the stem will thicken up. Eucalyptuses have quite pliable stems so I don't think you need worry unduly.

The most common Eucalyptus grown in our gardens is Eucalyptus gunnii which can grow up to 6in (15.2cm) a year in good conditions. It's this very rapid rate of growth can take people unawares and the tree can eventually become quite unmanageable. This isn't a problem if you take action to remove the top of the tree when this is within reach, however, and it will to some extent 'bush out' near the top, though as stated above, sooner or later a leading shoot will take over and extend the upwards growth again.

There is another reason for pruning Eucalyptus gunnii, however, and that is that it has two types of foliage. Eventually the tree starts to bear adult foliage with long lance shaped greener leaves, but when it is young the leaves are rounder and a grey/blue colour which is quite attractive and often used in flower arrangements. By pruning when the plant is maybe 6in (15.2cm) high down to about 2in (5cm) or 3in (7.6cm) high you will retain the juvenile more attractive foliage but, of course, the plant will never become very large - it really depends which leaf type you prefer.

Hope this helps.

Sibe

For further advice see Pruning Tips and To Prune Or Not To Prune.

The above picture is of a Cider Gum tree 'Eucalyptus gunnii' available from Crocus.