Repotting guide

When & how to repot Tasmanian Blue Gum (Eucalyptus globulus)

Also called blue gum eucalyptus, Tasmanian blue gum, fever tree.

More about tasmanian blue gum

About Tasmanian Blue Gum

Eucalyptus globulus · also called blue gum eucalyptus, Tasmanian blue gum · herb

Tasmanian blue gum is a fast-growing evergreen tree with aromatic, eucalyptol-rich foliage and striking silvery-blue juvenile leaves that mature to long sickle shapes. Often grown for cut foliage, screening, or as a container plant pruned for its round young leaves. It needs full sun, sharp drainage, and protection from hard frost, and can reach enormous size if left unpruned in the ground.

Mature size: 30-55 m as an unpruned forest tree; kept to 1-3 m as a coppiced shrub or container foliage plant.

Watch for — Wind-rock and toppling: Fast top growth on shallow roots makes tall trees unstable; plant small, stake while young, and don't over-fertilise.

How to tell tasmanian blue gum needs repotting

Repotting on a calendar is less reliable than reading the plant. For tasmanian blue gum, watch for these signs:

Roots circling the bottom of the module or pot, or poking out of the drainage holes.
The seedling dries out within a day and growth has visibly stalled.
Roots are white and matted in a tight spiral when you tip the plant out.
It has outgrown its current container for the stage of the season — pot tasmanian blue gum on before it becomes hard root-bound.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot tasmanian blue gum

Pot on seedlings as they grow; not a perennial repot. Tasmanian Blue Gumis grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Vigorous, upright evergreen tree; extremely fast-growing, can be coppiced or pollarded to keep juvenile round foliage and a manageable shrubby form..

What size pot to step tasmanian blue gum up to

Pot tasmanian blue gum on gradually — a seedling jumped straight into a huge pot sits in cold, wet, airless soil and stalls. Step up one or two sizes at a time as the roots fill each container, finishing in a large final pot or the ground. The aim is roots that never circle and never check.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot tasmanian blue gum

Pot tasmanian blue gum on through the active growing season, whenever roots fill the current container — there is no single date, just "before it becomes root-bound". Avoid potting on during a cold snap.

Step-by-step: repotting tasmanian blue gum

Pot on before it is root-bound. Check tasmanian blue gum regularly; move it up as soon as roots reach the edge of the cell or pot, not after they have circled.
Step up one or two sizes. Choose the next container up — not a giant one. Cold, wet, unused soil around a small root system stalls seedlings.
Knock it out gently. Support the stem, tip the pot, and ease the rootball out without breaking it. A little teasing of circled roots at the base is fine.
Pot into rich mix. Set it into fresh free-draining loam or sandy soil at the same depth (tomatoes are the exception — they can go deeper to root along the stem).
Water in and grow on. Water well, keep it in good light, and resume feeding once it is established and growing again.

Aftercare

Water tasmanian blue gum in well and keep it in bright light; a freshly potted-on seedling can wilt for a day while roots settle, so do not overcompensate by drowning it. Do not fertilise for about 1 week — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for tasmanian blue gum

Tasmanian Blue Gum wants free-draining loam or sandy soil. Well-drained, moderately fertile soil; tolerates poor and acidic ground but dislikes heavy, wet clay and prefers a slightly acidic to neutral pH. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting tasmanian blue gum — frequently asked questions

How often should you repot tasmanian blue gum?

Pot on seedlings as they grow; not a perennial repot for tasmanian blue gum. Tasmanian Blue Gum is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into free-draining loam or sandy soil so the roots never circle the cell, ending in a large final container. A root-bound transplant stalls and never fully recovers.

What size pot does tasmanian blue gum need?

When is the best time of year to repot tasmanian blue gum?

Can you put tasmanian blue gum straight into a much bigger pot?

No. Even a fast-growing tasmanian blue gum should only go up one pot size at a time. A vastly oversized pot holds a reservoir of wet soil the roots cannot reach, which stays cold and soggy and rots the roots — the opposite of what you wanted.

Should you fertilise tasmanian blue gum after repotting?

Not immediately. Wait about 1 week after repotting tasmanian blue gum. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.