Best Fertiliser for Plum Trees – Growth, Fruit Set & Feeding Guide

Plum trees are rewarding fruit trees for Australian home gardens, producing sweet, juicy fruit from summer through early autumn. To achieve healthy growth and a heavy fruit set, it’s essential to understand their nutritional needs and seasonal feeding requirements.

There are two main types of plum trees grown in Australia: Japanese plums (Prunus salicina) and European plums (Prunus domestica). Japanese varieties tend to fruit earlier and are popular in warmer regions, while European types thrive in cooler climates and are often used for drying and preserving.

Plum trees follow a seasonal cycle with three critical stages: dormancy in winter, flowering in late winter to spring, and fruit development in summer. Each stage requires a different nutrient focus. During spring, nitrogen encourages new leaf and branch growth. As the tree transitions to flowering and fruiting, phosphorus and potassium are key for blossom strength, pollination success, and fruit size.

Micronutrients such as calcium, magnesium, and iron are also important for healthy foliage and preventing disorders like leaf yellowing or fruit drop. Trees growing in sandy soils or containers may need more frequent feeding because nutrients leach quickly.

By understanding these growth stages and nutrient requirements, gardeners can time fertiliser applications for maximum benefit, leading to vigorous trees and an abundant harvest of plums each year.

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When and How to Fertilise Plum Trees in Australia

Correct timing and application of fertiliser are crucial to keeping plum trees healthy and productive. In Australia, seasonal feeding typically follows this pattern:

Late Winter (Pre-Flowering): Apply a balanced fertiliser as buds begin to swell. This feeds new shoots and encourages strong spring growth.
Spring (Flowering and Fruit Set): Support flowers and developing fruit with a fertiliser containing higher potassium and sufficient phosphorus to enhance pollination and prevent fruit drop.
After Harvest (Late Summer to Early Autumn): Apply a lighter feed to restore nutrients after fruiting. This helps the tree store energy for next year’s crop.

Young trees (1–3 years) need more nitrogen for vegetative growth, but mature fruiting trees benefit from a balanced NPK ratio that supports both foliage and fruit production. Avoid excessive nitrogen during flowering as it can result in leafy growth at the expense of fruit set.

Plum trees also respond well to deep watering after fertilising. This ensures nutrients penetrate the root zone and are readily absorbed. Mulching around the drip line with organic material (kept away from the trunk) helps retain moisture and improve soil health.

Regular observation is key: pale leaves may indicate a nitrogen deficiency, while poor flowering or small fruit can signal low potassium. Correcting these with a complete, water-soluble fertiliser keeps trees vigorous and productive year after year.

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Choosing the Best Fertiliser for Plum Trees

Plum trees perform best with a balanced, complete fertiliser that provides all major nutrients (NPK) and essential trace elements. For home gardeners, a water-soluble formula makes feeding easier and ensures rapid nutrient uptake during critical growth stages.

We recommend using CompleteGrow All Purpose NPK 20-20-20 Fertiliser. Its balanced formula supports healthy leaf growth, flower formation, and fruit development in plum trees. Apply it as a diluted solution around the root zone during active growth periods for reliable results.

By maintaining a regular feeding schedule and monitoring seasonal needs, you can ensure your plum trees stay healthy and produce abundant, high-quality fruit each year.

FAQs – Fertilising Plum Trees

When should I fertilise plum trees in Australia?
Fertilise in late winter before bud break, again in spring for fruiting, and lightly after harvest to replenish nutrients.
What fertiliser helps plum trees produce more fruit?
A balanced NPK fertiliser with higher potassium supports flower strength and improves fruit set and size.
Can I use the same fertiliser for all fruit trees?
Yes, a complete NPK fertiliser like 20-20-20 is suitable for most fruit trees, though timing may vary.
Do young plum trees need different feeding?
Young trees benefit from slightly higher nitrogen to promote branch and leaf growth, while mature trees need balanced feeding for fruiting.
Should I water after fertilising?
Always water deeply after applying fertiliser to help nutrients reach the root zone and prevent fertiliser burn.