Summer Fertilization Guide for Plumeria – Bloom Support & Stress Management

Summer is the height of the growing season for plumeria. With long days, rising temperatures, and heavy blooming underway, nutrient demands shift sharply. Your fertilization strategy in summer must balance bloom support with stress management—fueling vibrant flower production without overloading roots or pushing soft growth. This guide outlines how to feed plumeria effectively through summer, from June through August, using slow-release and supplemental liquid feeding approaches.

Why Summer Fertilization Is Unique

During summer, plumeria are often in full bloom or approaching peak flowering. Unlike spring, when the goal is structural growth and root establishment, summer feeding must:

• Support inflorescence formation and flowering
• Replenish nutrients lost to heat and frequent watering
• Avoid high nitrogen, which promotes weak, leggy stems
• Prevent bloom drop and leaf chlorosis due to micronutrient loss
• Help roots cope with increased heat and salt stress

Fertilizer uptake also varies with temperature: in extreme heat (95°F+), roots slow down nutrient absorption, so timing and dilution matter.

Core Summer Fertilization Goals

Month-by-Month Fertilizer Schedule (Zone 10a Example)

June – Support Peak Growth and First Blooms

• Apply Excalibur VI or IX (if not already applied in spring)
  • Rate: 1 cup per mature tree, ½ cup for young plants
  • Where: Apply around the dripline and water deeply
• Start liquid bloom support every 10–14 days:
  • Fish emulsion + kelp or a low-NPK bloom booster (e.g., 2-3-2 or 0-10-10)
• Optional foliar spray: Kelp + Epsom salt to boost bud retention and petal resilience

July – Maintain Bloom and Stress Resilience

• Do not reapply granular fertilizer unless your last feeding was over 12 weeks ago
• Continue liquid bloom support every 10–14 days
  • Rotate with compost tea, worm tea, or humic acid to support root health
• Foliar spray combo:
  • Seaweed extract (1 tbsp/gal)
  • Epsom salt (1 tsp/gal)
  • Apply early morning every 2–3 weeks

Monitor for:

• Leaf yellowing (possible magnesium or iron deficiency)
• Flower drop (often from underwatering or salt stress)
• Pale new growth (micronutrient imbalance)

August – Post-Bloom Maintenance and Nutrient Rebalance

• Taper liquid feedings to every 2–3 weeks
• Introduce worm tea or compost tea monthly to refresh soil biology
• Avoid high-phosphorus products this late unless in active bloom
• Prepare for the final granular top-up (Excalibur Boost) in early September if needed

Fertilizer Product Recommendations

Feeding Based on Plant Location

Container-Grown Plumeria

• Use 50–75% strength of the standard fertilizer rates
• Flush containers monthly to remove salt buildup
• Monitor for dry edges or leaf curl as signs of salt stress
• Apply worm tea or compost tea as a conditioner every 3–4 weeks

Raised Beds

• Water deeply before feeding in hot conditions
• Use full-rate granular in early June (if not already applied)
• Apply compost tea monthly to maintain moisture retention and microbe activity

In-Ground Trees

• Fertilize only if rainfall is frequent enough to leach nutrients
• Use foliar sprays or compost tea as bloom support if granular was applied in spring
• Add mulch to moderate heat and reduce soil evaporation

Summer Feeding Tips and Warnings

• Never fertilize dry soil – Water first to prevent root burn
• Avoid applying in midday sun – Fertilize early morning or after 5 PM
• Skip high-nitrogen blends – May cause soft stems and weak inflorescence
• Don’t feed wilted or heat-stressed plants – Allow recovery first
• Always dilute liquids – Summer root systems are more sensitive

Signs of Overfeeding in Summer

• Rapid stem elongation or “leggy” growth
• Leaf tip burn or marginal browning
• Salt crust on the soil surface
• Flower drop or shortened bloom cycle
• Sudden leaf yellowing without pests present

If these symptoms appear, flush the soil with plain water and pause all feeding for 2–3 weeks.

Conclusion

• Summer fertilization for plumeria focuses on flower support, micronutrient balance, and root health
• Use slow-release granular for base feeding, supplemented with diluted organic liquids
• Tailor the schedule to match your tree’s growth stage, planting location, and climate intensity
• Monitor closely for stress signs, adjust feeding strength, and prioritize consistency over intensity
• A balanced summer feeding strategy produces strong blooms and a resilient plant heading into fall