Repotting guide

When & how to repot Thornless Evergreen Blackberry (Rubus laciniatus 'Thornless Evergreen')

Also called thornless evergreen blackberry, cutleaf blackberry.

More about thornless evergreen blackberry

About Thornless Evergreen Blackberry

Rubus laciniatus 'Thornless Evergreen' · also called thornless evergreen blackberry, cutleaf blackberry · edible

'Thornless Evergreen' is a vigorous, semi-evergreen blackberry with deeply cut leaves and long, thornless canes that crop heavily in late summer. Productive and easy to harvest, it yields firm, flavourful berries that freeze well, holds its foliage in mild winters, and trains neatly along wires or fences for the home grower.

Mature size: Canes 2-4.5 m long, trained to 1.5-2 m on wires; spreads via tip-rooting and suckers.

Watch for — Tip-rooting spread: Cane tips touching the soil root and form new plants, letting it wander. Keep tips off the ground and remove rooted shoots you don't want.

How to tell thornless evergreen blackberry needs repotting

Repotting on a calendar is less reliable than reading the plant. For thornless evergreen blackberry, 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 thornless evergreen blackberry 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 thornless evergreen blackberry

Pot on seedlings as they grow; not a perennial repot. Thornless Evergreen Blackberryis grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Vigorous, semi-evergreen trailing to semi-erect blackberry with very long, thornless biennial canes. Fruit forms on second-year (floricane) canes; canes need training and tying onto a support..

What size pot to step thornless evergreen blackberry up to

Pot thornless evergreen blackberry 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 thornless evergreen blackberry

Pot thornless evergreen blackberry 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 thornless evergreen blackberry

Pot on before it is root-bound. Check thornless evergreen blackberry 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 fertile, well-drained loam 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 thornless evergreen blackberry 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 thornless evergreen blackberry

Thornless Evergreen Blackberry wants fertile, well-drained loam. Thrives in deep, fertile, free-draining soil rich in organic matter with a pH of 5.5-7.0. Adaptable to a range of soils provided drainage is good; persistently wet ground causes root problems. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting thornless evergreen blackberry — frequently asked questions

How often should you repot thornless evergreen blackberry?

Pot on seedlings as they grow; not a perennial repot for thornless evergreen blackberry. Thornless Evergreen Blackberry is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into fertile, well-drained loam 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 thornless evergreen blackberry need?

When is the best time of year to repot thornless evergreen blackberry?

Can you put thornless evergreen blackberry straight into a much bigger pot?

No. Even a fast-growing thornless evergreen blackberry 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 thornless evergreen blackberry after repotting?

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