Best Fertiliser for Bougainvillea

Bougainvillea is famous for its brilliant bracts, but it only delivers its full display when fed correctly. Choosing the best fertiliser ensures strong roots, healthy foliage, and repeat cycles of colour throughout the year. The two most effective options are balanced fertilisers that encourage growth and formulas tailored to flowering, both of which are available in the CompleteGrow range. By using these products consistently, you can achieve vigorous growth and non-stop colour in bougainvillea planted in the ground or in pots.

Why Bougainvillea Needs Fertiliser

Although bougainvillea is hardy and drought-tolerant, it is a heavy feeder when actively growing. Each flush of flowers requires significant energy, and without fertiliser the plant quickly loses strength. While it may still survive in poor soil, unfed bougainvillea often produces more leaves than flowers, and its colours fade sooner.

Benefits of fertilising bougainvillea:

Encourages repeat flowering across the growing season.
Supports strong root and stem development.
Enhances colour intensity in bracts.
Improves resilience in pots where nutrients wash away quickly.

The key is applying fertiliser regularly in balanced doses. Over-fertilising with nitrogen leads to leafy growth with few flowers, while underfeeding leaves the plant weak. A complete approach ensures health and colour.

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CompleteGrow Fertilisers for Bougainvillea

For the best results, bougainvillea should be fed with fertilisers that balance overall growth and maximise flowering. CompleteGrow offers two highly effective options:

🌿 All Purpose Plant Liquid Fertiliser (NPK 20-20-20):
This balanced formula is ideal for regular feeding. It provides equal amounts of nitrogen, phosphorus, and potassium, ensuring strong root systems, healthy green foliage, and consistent flowering. Use at 4ml per litre every 2–3 weeks for both in-ground and potted bougainvillea.

🌸 Advanced Formula NPK 4-18-38 + Calcium & Magnesium:
This specialised formula is designed to push bougainvillea into its best flowering performance. The high potassium content supports bract production and colour intensity, while phosphorus boosts roots and calcium–magnesium strengthens leaf tissue. This fertiliser is especially effective during peak growing and flowering seasons when bougainvillea is producing repeated flushes of colour.

Many gardeners alternate between the two: using the NPK 20-20-20 as a steady base feed, and switching to the 4-18-38 + CaMg when aiming for maximum flowers.

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Feeding Tips, Schedule, and FAQs

For best results, water bougainvillea lightly before applying fertiliser to avoid root burn. Fertilise every 2–3 weeks in pots and every 3–4 weeks in the ground during active growth. Reduce feeding in winter when the plant slows down but keep some nutrients available to maintain health.

Consistency is more effective than heavy feeding. A measured routine using CompleteGrow’s fertilisers ensures bougainvillea stays strong and colourful throughout the year.

Frequently Asked Questions

What is the best fertiliser for bougainvillea?
A balanced formula such as CompleteGrow’s All Purpose Plant Liquid Fertiliser (NPK 20-20-20) works for everyday care, while the Advanced Formula NPK 4-18-38 + Calcium & Magnesium is ideal for maximising blooms.

How often should bougainvillea be fertilised?
Every 2–3 weeks in pots and every 3–4 weeks in the garden during active growth. Reduce frequency in winter when growth slows.

Why is my bougainvillea growing leaves but no flowers?
This usually happens when nitrogen is too high or sunlight is lacking. Use a high-potassium fertiliser like CompleteGrow’s 4-18-38 + CaMg and ensure six hours of sun daily.

Can I use both fertilisers?
Yes. Use NPK 20-20-20 for balanced feeding throughout the year, and switch to or combine with 4-18-38 + CaMg when you want stronger flowering performance.