Excalibur, NutriStar, Nelson’s, Osmocote, and Bloom Booster Fertilizers Showdown

Which Fertilizer Wins for Healthy, Blooming Plumeria?

Choosing the right fertilizer is one of the most important decisions in successful plumeria care. With options ranging from slow-release blends to high-phosphorus bloom stimulants, it’s easy to be overwhelmed by product labels and marketing claims.

This guide compares Excalibur, NutriStar, Nelson’s, Osmocote Plus, and Bloom Boosters (like BR-61)—breaking down their formulas, use cases, risks, and how they affect plumeria health.

Overview Comparison

1. Excalibur (VI & IX) – Best Overall for Plumeria

Pros:

• Specifically designed for plumeria
• Low salt index = safer for roots and stems
• Excellent NPK balance for sustained health and blooming
• Chelated micronutrients improve uptake
• No clumping or fungal slime
• Long-lasting with no need to supplement

Cons:

• Not widely available in retail (Florida Colors Nursery exclusive or authorized sellers)
• Higher up-front cost than short-term fertilizers

Use Excalibur VI for:

• Containers (All Sizes)
• In-Ground Plumeria (Zones with 6+/- month or 12+/- month seasons)
• Cuttings (after rooting)
• Seasonal refreshes

Use Excalibur IX for:

• Containers (All Sizes)
• In-Ground plumeria (Zones with 9+/- month seasons)
• Growers who want to fertilize only once per year

✅ Safe, balanced, and designed specifically for plumeria. Best overall performance and least risk.

2. NutriStar Plumeria – Quick Boost, Not Long-Term

Pros:

• Water-soluble + slow-mix combo for fast-acting nutrients
• High phosphorus (P) for flowering
• Includes micronutrients
• Available at garden centers

Cons:

• High phosphorus and moderate salt index can lead to stem tip burn if overapplied.
• Short lifespan—requires frequent reapplication
• Not ideal in humid climates or with composted soils

Use For:

• A quick bloom push at the start of the flowering season
• A spring pick-me-up for plants not blooming on time
• Backup for Excalibur if slow-release isn’t available

⚠️ Should not be your main fertilizer. Use sparingly and never near stems.

3. Nelson Plumeria – Mid-Season Bloom Spike Option

Pros:

• High-phosphorus formula to encourage heavy blooming
• Includes micronutrients
• Widely available and marketed for plumeria

Cons:

• Moderate to high salt index, risk of rot in containers or wet conditions
• Requires reapplication every 2–3 months
• May suppress microbial life in the soil
• Overuse leads to nutrient imbalance and poor root performance

Use For:

• Established, in-ground plumeria needing bloom support
• A controlled application in early summer, if no slow-release was used

⚠️ Not ideal for regular use in pots or near newly rooted cuttings.

4. Osmocote Plus – Good General-Use Fertilizer

Pros:

• Slow-release coated pellets
• Available in most garden centers
• Moderate, balanced NPK with micronutrients
• Suitable for landscape use, including ornamentals

Cons:

• Not designed specifically for plumeria
• May promote more foliage than flowers
• Nutrient ratios are not ideal for the blooming phase
• Coatings may underperform in extreme heat/humidity

Use For:

• Landscape-grown plumeria with regular rainfall
• Supplementing new growers who don’t yet use Excalibur

⚠️ Decent option—but not optimized for plumeria’s blooming cycle.

5. Bloom Booster (e.g., BR-61, 9-58-8) – Emergency-Use Only

Pros:

• An extreme phosphorus spike can trigger blooming
• Fast-acting and water-soluble
• Useful in nutrient-poor soils or stressed plants

Cons:

• An extremely high salt index can burn roots and stems
• No micronutrients
• Not sustainable, leads to deficiencies, and salt buildup
• Encourages top-heavy growth and flower drop if overused

Use ONLY For:

• One-time bloom stimulation in a healthy, established plant
• Foliar feed diluted heavily (¼ strength)
• Last resort before an event or show

❌ Not for containers, seedlings, or long-term use. Causes more harm than good if misused.

Final Verdict

Conclusion

When it comes to plumeria, not all fertilizers are created equal. Excalibur VI and IX remain the top-performing and safest choices, designed specifically to meet the plant’s nutrient demands. NutriStar and Nelson’s can work as occasional bloom stimulants but carry higher salt and burn risks. Osmocote is a suitable general alternative, while Bloom Boosters should be treated like a last resort.

The best strategy: use Excalibur as your base, and supplement wisely only if needed.