Why Is My Blackberry Plant Not Growing?

A blackberry plant that produces only a few short, weak canes per year — or that makes almost no growth at all after planting — is telling you something is wrong at the root zone or in the soil. Blackberries are otherwise vigorous plants that under good conditions send up multiple long canes from the base each summer. When growth stalls, the most common causes are: poor planting depth, waterlogged or compacted soil, nutrient deficiency, root damage, or a genuinely poor planting site.

Check the planting depth

The crown — the transition point between roots and the above-ground cane base — should sit at soil level, not buried below it. If the plant was planted deeply, dig gently around the base and check. A buried crown often shows signs of rot. Where the soil has settled significantly, carefully lift the plant and replant at the correct depth. This is best done in autumn or very early spring when the plant is dormant.

Soil drainage and compaction

Blackberries need well-drained soil. Waterlogged, compacted or clay-heavy soil produces slow or absent growth because the root system cannot function properly in anaerobic conditions. Fork the soil around the plant to improve aeration. In persistently wet spots, raised planting on a slight mound or bed improves drainage enough to make a significant difference. Adding organic matter — well-rotted compost or leaf mould worked into the planting area — improves both drainage and aeration in heavy soils.

Feeding for vigour

A well-fed blackberry plant is a vigorous one. In early spring, apply a general balanced fertiliser (e.g. Growmore) at the manufacturer's rate around the base of the plant. Follow up with a mulch of well-rotted compost or manure. If the soil is very acidic (below pH 5.5) or very alkaline (above pH 7.5), nutrient availability is reduced regardless of what is applied — test and adjust soil pH if the soil has not been checked recently. Blackberries prefer a pH of 5.5 to 7.0.

Root damage and competition

Roots severed by careless hoeing or digging near the plant, or a root system competing with grass or weeds right at the crown, both reduce vigour. Keep a clear, mulched area of at least 50 cm radius around each plant free from grass and weeds, particularly in the first two to three years of establishment.